Session 5

Question 1

Describe the structures that form the knee joint, including the bones, ligaments, menisci, joint capsule & bursae

1. The knee joint is a ? type synovial joint, which mainly allows for ?. It is formed by articulations between the ?
2. The knee joint consists of two articulations:
3. The ? joint is the weight-bearing joint of the knee.
4. The patellofemoral joint allows the tendon of the ? to be inserted directly over the knee, increasing the efficiency of the muscle. Both joint surfaces are lined with hyaline cartilage, & enclosed within a single joint cavity.
5. The patella is formed inside the tendon of the quadriceps femoris; its presence minimises ?
6. Neurovascular supply to knee joint
7. The medial & lateral menisci are fibrocartilage structures in the knee that serve two functions:
8. They are C shaped, and attached at both ends to the ?
9. The medial meniscus is fixed to the ? Any damage to the tibial collateral ligament results in ?
10. How if the lateral meniscus different, why is this important?

Answer 1

1. bicondylar, flexion and extension (& a small degree of medial & lateral rotation), patella, femur & tibia.
2. Tibiofemoral – The medial & lateral condyles of the femur articulating with the tibia.

Patellofemoral – The anterior & distal part of the femur articulating with the patella.

3. tibiofemoral
4. quadriceps femoris (the main extensor of the knee)
5. wear & tear on the tendon
6. genicular anastomoses around the knee, which are supplied by the genicular branches of the femoral & popliteal arteries.

The nerve supply, according to Hilton’s law, is by the nerves which supply the muscles which cross the joint. These are the femoral, tibial & common fibular nerves.

7. To deepen the articular surface of the tibia, thus increasing stability of the joint.

To act as shock absorbers.

8. intercondylar area of the tibia
9. Tibial collateral ligament & the joint capsule, tearing of the medial meniscus
10. smaller & does not have any extra attachments, rendering it fairly mobile

Question 2

Answer 2

Question 3

Answer 3

Question 4

Answer 4

Question 5

1. A bursa is
2. There are 5 bursae found in the knee joint:

Answer 5

1. synovial fluid filled sac, found between moving structures in a joint – with the aim of reducing wear and tear on those structures.
2. Suprapatella bursa – This is an extension of the synovial cavity of the knee, located between the quadriceps femoris and the femur.

Subcutaneous Prepatella bursa – Found between the apex of the patella and the skin.

Infrapatella bursa – Split into deep and superficial. The deep bursa lies between the tibia and the patella ligament. The superficial lies between the patella ligament and the skin.

Semimembranosus bursa – Located posteriorly in the knee joint, between the semimembranosus muscle and the medial head of the gastrocnemius.

Question 6

Give a detailed description of the ligaments associated with the knee joint and understand the role of each ligament in maintaining stability

The major ligaments in the knee joint are: (5) state origins & insertions

Answer 6

1. Patellar ligament – A continuation of the quadriceps femoris tendon distal to the patella. It attaches to the tibial tuberosity.
2. Collateral ligaments – These are two strap-like ligaments. They act to stabilise the hinge motion of the knee, preventing any medial or lateral movement

Tibial (medial) collateral ligament – A wide and flat ligament, found on the medial side of the joint. Proximally, it attaches to the medial epicondyle of the femur, distally it attaches to the medial surface of the tibia.

Fibular (lateral) collateral ligament – Thinner & rounder than the tibial collateral, this attaches proximally to the lateral epicondyle of the femur, distally it attaches to a depression on the lateral surface of the fibular head.

3. Cruciate Ligaments – These two ligament connect the femur and the tibia. In doing so, they cross each other, hence the term ‘cruciate’ (Latin for like a cross)

Anterior cruciate ligament – attaches at the anterior intercondylar region of the tibia and ascends posteriorly to attach to the femur, in the intercondylar fossa. It prevents anterior dislocation of the tibia onto the femur.

Posterior cruciate ligament – attaches at the posterior intercondylar region of the tibia, and ascends anteriorly to attach to the femur in the intercondylar fossa. It prevents posterior dislocation of the tibia onto the femur.

Question 7

Describe the movements of the knee joint & the muscles involved.

There are four main movements that the knee joint permits:

Answer 7

Extension: Produced by the quadriceps femoris, which inserts into the tibial tuberosity.

Flexion: Produced by the hamstrings, gracilis, sartorius & popliteus.

Lateral rotation: Produced by the biceps femoris.

Medial rotation: Produced by five muscles; semimembranosus, semitendinosus, gracilis, sartorius & popliteus.

NB: Lateral & medial rotation can only occur when the knee is flexed (if the knee is not flexed, the medial/lateral rotation occurs at the hip joint).

Question 8

Fractures of the distal femur & proximal tibia (recognise on X-rays & MRI scans) LO

1. Epidemiology
2. Mechanism young patients
3. Classification

Answer 8

1. traditionally young patients but increasing in geriatric population

bimodal distribution: young, healthy males, elderly osteopenic females

periprosthetic fractures becoming more common

2. high energy with significant displacement

older patients

low energy, often fall from standing, in osteoporotic bone, usually with less displacement

3. Descriptive

supracondylar

intercondylar

OTA: 33

A: extraarticular

B: partial articular

portion of articular surface remains in continuity with shaft

33B3 is in coronal plane (Hoffa fragment)

C: complete articular

articular fragment separated from shaft

Question 9

Patellar fractures

1. In a patellar dislocation, the patella bone is displaced out of the ?
2. It accounts for around 3% of knee injuries. Most dislocations occur ?, and are caused by ?
3. These mechanisms of injury make patellar dislocation more common in individuals participating in sports such as: ?

Dislocations

4. Patellar fractures usually result from ?
5. They are more common in ?
6. If the patella fractures into fragments, they will usually separate; the proximal fragment displaced ? by the ? & the distal fragment pulled ? by the ?

Answer 9

1. patellofemoral groove
2. laterally, high force impact on the patella or forceful sudden twisting of the knee
3. football, rugby & ice hockey.
4. • direct trauma to the bone
     - sudden contraction of the quadriceps muscle
5. males, & in the 20-50 age range
6. superiorly, quadriceps tendon, inferiorly, patellar ligament

Question 10

What is this image showing

Answer 10

Patella tendon rupture

Question 11

What is this image showing

Answer 11

Patella tendon rupture

Question 12

What is this image showing

Answer 12

Quadriceps rupture

Question 13

What is this image showing

Answer 13

Patella fracture

Question 14

What is this image showing

Answer 14

Patella dislocation

Question 15

What is this image showing

Answer 15

PATELLAR DISLOCATION OSTEOCHONDRAL

APD can lead to osteochrodral injury osteochondral injury is an injury to the smooth surface on the end of bones, called articular cartilage (chondro), and the bone (osteo) underneath it

Question 16

Meniscal injuries

Answer 16

Question 17

What is this image showing

Answer 17

Meniscal injury

Question 18

Collateral ligament injuries

1. Injury to the collateral ligaments is the most common pathology affecting the knee joint. It is caused by ?
2. Damage to the collateral ligaments can be assessed by asking the patient to ?
3. If the tibial collateral ligament is damaged, it is more than likely that the ?
4. What is the unhappy triad

Answer 18

1. Force being applied to the side of the knee when the foot is placed on the ground
2. medially rotate & laterally rotate the leg. Pain on medial rotation indicates damage to the medial ligament, pain on lateral rotation indicates damage to the lateral ligament.

Lateral collateral ligament (LCL)

Below are instructions to examine the right knee – change your hands for the left knee

1. Extend the patient’s knee fully.
2. Hold the patient’s ankle between your elbow and side.
3. Place your right hand along the medial aspect of the knee.
4. Place your left hand on the lower limb (e.g. calf or ankle).
5. Push steadily outward with your right hand whilst applying an opposite force with the left.
6. If the LCL is damaged your hand should detect the lateral aspect of the joint opening up.

Medial collateral ligament (MCL)

Below are instructions to examine the right knee – change your hands for the left knee

1. Extend the patient’s knee fully.
2. Hold the patient’s ankle between your elbow and side.
3. Place your right hand along the lateral aspect of the knee.
4. Place your left hand on the lower limb (e.g. calf or ankle).
5. Push steadily inward with your right hand whilst applying an opposite force with the left.
6. If the MCL is damaged your hand should detect the medial aspect of the joint opening up.
   If after this assessment the knee appears stable you can further assess the collateral ligaments by repeating this test with the knee flexed at 30°. At this position, the cruciate ligament is not taught so minor collateral ligament laxity can be more easily detected.

With healthy collateral ligaments, there should be no abduction or adduction possible. If abduction/adduction is possible, it suggests laxity/rupture of the corresponding collateral ligament.

3. medial meniscus is torn, due to their attachment.
4. Due to the attachment of the medial collateral ligament to the medial meniscus, damage to the medial collateral can affect this important cartilaginous structure. A lateral force to an extended knee, such as a rugby tackle, can rupture the medial collateral ligament, damaging the medial meniscus in the process. The ACL is also affected, which completes the ‘unhappy triad’.

Question 19

What is this image showing?

Answer 19

Medial collateral ligament rupture

Question 20

Anterior & posterior cruciate ligament injuries

1. The anterior cruciate ligament (ACL) can be torn by ?
2. To test for this, you can perform an ?
3. The most common mechanism of posterior cruciate ligament (PCL) damage is the ?
4. To test for PCL damage, perform the:

5.

Answer 20

1. • hyperextension of the knee joint
     - large force to the back of the knee with the joint partly flexed
2. Anterior/Posterior drawer test
3. Flex the patient’s knee to 90º
4. Inspect for evidence of posterior sag as this can give a false positive anterior drawer sign
5. Wrap your hands around the proximal tibia with your fingers around the back of the knee
6. Sit on the patient’s lower leg to fix its position
7. Position your thumbs over the tibial tuberosity
8. Ask the patient to keep their legs as relaxed as possible (tense hamstrings can mask pathology).
9. Pull the tibia anteriorly and feel for any anterior movement of the tibia on the femur – significant movement maysuggest anterior cruciate laxity/rupture
10. Push the tibia posteriorly – significant movement may suggest posterior cruciate laxity/rupture

Lachman’s Test (most sensitive test for ACL rupture)

1. Flex the patient’s leg to 30°
2. Hold the lower leg with one hand with the thumb on the tibial tuberosity and the fingers on the calf
3. With the other hand hold the thigh just above the patella
4. Use the hand holding the lower leg to pull the tibia forward on the femur while the other hand stabilises the femur

Significant anterior movement of the tibia on the femur signifies anterior cruciate ligament laxity/rupture.

3. • ‘dashboard injury’ knee is flexed, & a large force is applied to the shins, pushing the tibia posteriorly. (This is often seen in car accidents, where the knee hits the dashboard.)
     - hyperextension of the knee joint, or by damage to the upper part of the tibial tuberosity.
4. Posterior draw test:

This is where the clinician holds the knee in flexed position, & pushes the shin posteriorly. If there is movement, the ligament has been torn.

Question 21

What is this image showing

Answer 21

ACL rupture

Question 22

What is this image showing

Answer 22

Tibial spine #

ACL attaches here

Question 23

Treatment

Answer 23

• Autograft – Hamstrings

Patellar tendon

• Allograft
• Synthetic – poor results
• We can’t replicate the original ACL

More common

Semitendinosus & membranous

Question 24

Housemaids knee

1. What is it ?
2. There are a number of different things that can cause housemaid’s knee:

Answer 24

1. prepatellar bursitis (inflammation of a small fluid-filled sac (the bursa) in front of the patella)
2. • A sudden, one-off, injury to the knee

This might be, for example, a fall or direct blow on to the knee.

- Recurrent minor injury to the knee

Friction between patella and skin/ pressure when kneeling down

• Infection

Common in children, usually follows a cut, scratch or injury to the skin on the surface of the knee.

- Another inflammatory disease

E.g. RA increased risk of developing a bursitis. Rheumatoid arthritis is a form of arthritis that causes inflammation, pain and swelling of joints.

Question 25

Superficial infrapatellar bursitis (clergyman’s knee) LO

1. Cause?

Answer 25

1. Friction between the skin & tibia can cause the infrapatella bursa to become inflamed

Question 26

1. What is this image showing?
2. What do patients normally present with?
3. Changes seen on the x-ray

Answer 26

1. Osteoarthritis
2. • Pain

• Stiffness
• Deformity (bow legs/loss of height)
• Joint swelling

3. • Decreased joint space

• Sclerosis (hardening of tissue)
• Osteophytes (bony projections)
• Bone cysts (fluid-filled hole that develops inside a bone)

Question 27

Femoral sheath LO

Answer 27

Question 28

1. The femoral triangle is a ?
2. As this area is a triangle, it has three borders:
3. It also has a floor & a roof:
4. The inguinal ligament acts as a ?
5. The femoral triangle contains some of the major neurovascular structures of the lower limb. Its contents (lateral to medial) are:
6. What is contained within the femoral sheath
7. A good way of remembering the contents is using the acronym NAVEL:

Answer 28

1. hollow area in the anterior thigh
2. Superior border – Formed by the inguinal ligament, a ligament that runs from the anterior superior iliac spine to the pubis tubercle.

Lateral border – Formed by the medial border of the sartorius muscle.

Medial border – Formed by the medial border of the adductor longus muscle. The rest of this muscle forms part of the floor of the triangle.

3. Anteriorly, the roof - fascia lata.

Posteriorly, the base - pectineus, iliopsoas & adductor longus muscles.

4. Flexor retinaculum, supporting the contents of the femoral triangle during flexion at the hip.
5. Femoral nerve – Innervates the anterior compartment of the thigh, & provides sensory branches for the leg & foot.

Femoral artery – Responsible for the majority of the arterial supply to the lower limb.

Femoral vein – The great saphenous vein drains into the femoral vein within the triangle.

Femoral canal – A structure which contains deep lymph nodes & vessels.

6. femoral artery, vein and canal are contained within a fascial compartment
7. N: Nerve.

A: Artery.

V: Vein.

E: Empty space (this is important as it allows the veins and lymph vessels to distend, so they can cope with different levels of flow).

L: Lymph canal.

Question 29

Answer 29

Question 30

Answer 30

Question 31

Clinical Relevance of the Femoral Triangle:

Answer 31

Femoral Pulse

Access to the Femoral Artery

Femoral Hernia

Question 32

Femoral Pulse

1. Where can it be palpated?
2. The femoral artery crosses exactly midway between the ?
3. The presence of a femoral pulse means?

Answer 32

1. Just inferior to where the femoral artery crosses the inguinal ligament, it can be palpated to measure the femoral pulse.
2. pubis symphysis & anterior superior iliac spine.
3. that blood is reaching the lower extremity

Question 33

Access to the Femoral Artery

1. The femoral artery is located ? within the femoral triangle, & is thus easy to access. This makes it suitable for a range of clinical procedures.
2. One such procedure is coronary angiography. Describe the procedure

Answer 33

1. superficially
2. • Femoral artery catheterised with a long, thin tube.
     - Tube is navigated up the external iliac artery, common iliac artery, aorta, and into the coronary vessels. A radio-opaque dye is then injected into the coronary vessels, & any wall thickening or blockages can be visualised via x-ray.

Question 34

Femoral Hernia

1. A hernia is defined as?
2. In the case of femoral hernia, part of the bowel pushes into the ?

This manifests clinically as a lump or bulge in the area of the femoral triangle. It usually requires surgical intervention to treat.

Answer 34

1. a condition in which part of an organ is displaced and protrudes through the wall of the cavity containing it
2. femoral canal, underneath the inguinal ligament

Question 35

1. The main artery of the lower limb is the ? It is a continuation of the ?
2. The external iliac becomes the femoral artery when ?
3. In the femoral triangle, the ? artery arises from the posterolateral aspect of the femoral artery. It travels posteriorly & distally, giving off three main branches:

Answer 35

1. femoral artery
2. external iliac artery (terminal branch of the abdominal aorta)
3. It crosses under the inguinal ligament & enters the femoral triangle
4. Profunda femoris:

Perforating branches – Consists of three or four arteries that perforate the adductor magnus, contributing to the supply of the muscles in the medial & posterior thigh.

Lateral femoral circumflex artery – Wraps round the anterior, lateral side of the femur, supplying some of the muscles in the lateral side of the thigh.

Medial femoral circumflex artery – Wraps round the posterior side of the femur, supplying the neck & head of the femur. In a fracture of the femoral neck, this artery can easily be damaged, & avascular necrosis of the femur head can occur.

Question 36

1. After exiting the femoral triangle, the femoral artery continues down the anterior surface of the thigh, via a tunnel known as the ?
2. During its descent the artery supplies the anterior thigh muscles.

The adductor canal ends at an opening in the adductor magnus, called the ? The femoral artery moves through this opening, & enters the posterior compartment of the thigh, proximal to the knee. The femoral artery now known as the ?

Answer 36

1. adductor canal
2. adductor hiatus, popliteal artery

Question 37

1. The ? arises from internal iliac artery in the pelvic region. It descends via the obturator canal to enter the medial thigh, bifurcating into two branches: state the branches and what muscles they supply
2. The gluteal region is largely supplied by the ? These arteries also arise from the ?, entering the gluteal region via the ?
3. The superior gluteal artery leaves the foramen above the ? muscle, the inferior below the muscle. In addition to the gluteal muscles, the inferior gluteal artery also contributes towards the vasculature of the posterior thigh.

4.

Answer 37

1. obturator artery
2. Anterior branch – This supplies the pectineus, obturator externus, adductor muscles and gracilis.

Posterior branch – This supplies some of the deep gluteal muscles.

2. superior & inferior gluteal arteries, internal iliac artery, greater sciatic foramen
3. piriformis

4.

Question 38

Answer 38

Question 39

1. The popliteal artery descends down the posterior thigh, giving off ? branches that supply the knee joint. It moves through the popliteal fossa, exiting sandwiched between the ? muscles.
2. At the lower border of the popliteus, the popliteal artery terminates by dividing into ?
3. The posterior tibial artery continues inferiorly, along the surface of the deep muscles (such as tibialis posterior). It accompanies the tibial nerve in entering the sole of the foot via the ?. During the descent of the posterior tibial artery in the leg, the ? artery arises. This artery moves laterally, penetrating the lateral compartment of the leg. It supplies muscles in the lateral compartment, and adjacent muscles in the posterior compartment.
4. The other division of the popliteal artery, the anterior tibial artery, passes anteriorly between the tibia & fibula, through a gap in the ? It then moves inferiorly down the leg. It runs down the entire length of the leg, and into the foot, where it becomes the ?

Answer 39

1. genicular, gastrocnemius & popliteus
2. anterior & posterior tibial arteries
3. tarsal tunnel, fibular
4. interosseous membrane, dorsalis pedis artery.

Question 40

Answer 40

Question 41

Answer 41

Question 42

Clinical relevance of the popliteal artery?

Answer 42

Question 43

1. Arterial supply to the foot is delivered via two arteries:
2. The dorsalis pedis artery begins as the anterior tibial artery enters the foot. It passes over the dorsal aspect of the tarsal bones, then moves inferiorly, towards the sole of the foot. It then anastamoses with the ?
3. The dorsalis pedis artery supplies the tarsal bones & the dorsal aspect of the metatarsals. Via the ?, it also contributes to the supply of the toes.
4. The posterior tibial artery enters the sole of the foot through the ? It then splits into the lateral & medial plantar arteries. These arteries supply the plantar side of the foot, & contributes to the supply of the toes via the deep plantar arch.

Answer 43

1. • Dorsalis pedis (a continuation of the anterior tibial artery)
     - Posterior tibial
2. lateral plantar artery to form the deep plantar arch
3. deep plantar arch
4. tarsal tunnel

Question 44

Clinical Relevance:

Answer 44

Pulse Points in the Lower Limb

Question 45

1. There are three main pulse points in the lower limb;
2. The femoral pulse can be palpated as it enters the femoral triangle, midway between the anterior superior iliac spine of the pelvis, and the pubis synthesis (?).
3. The popliteal artery is the hardest pulse to find. It lies deep in the popliteal fossa, and requires deep palpation to feel. To make it easier, you can ask the patient to slightly ?
4. The dorsalis pedis pulse is found by palpating where?

Answer 45

1. femoral, popliteal & dorsalis pedis
2. the mid-inguinal point
3. flex their leg – this relaxes the fascia around the popliteal fossa.
4. on the dorsum of the foot, just lateral to extensor hallucis longus tendon

Question 46

1. The veins of the lower limb drain deoxygenated blood & return it to the heart. They can be divided into two groups – deep & superficial:

Deep veins are located ?

Superficial veins are found in the ?

2. The artery & deep vein are located within the same vascular sheath – why?
3. The Foot & Leg

The main venous structure of the foot is the ?, which mostly drains into the superficial veins. Some veins from the arch penetrate deep into the leg, forming the ?

4. On the plantar aspect of the foot, ? veins arise. These veins combine to form the ?
5. The posterior tibial vein accompanies the posterior tibial artery, entering the leg posteriorly to the ?.
6. On the

posterior surface of the knee, the anterior tibial, posterior tibial and fibular veins unite to form the ?. The popliteal vein enters the thigh via the ?

8. The Thigh

Once the popliteal vein has entered the thigh, it is known as the ? vein. It is situated anteriorly, accompanying the femoral artery.

9. The deep vein of the thigh (? vein) is the other main venous structure in the thigh. Via perforating veins, it drains blood from the thigh muscles. It then empties into the distal section of the femoral vein.
10. The femoral vein leaves the thigh by running underneath the inguinal ligament, at which point it is known as the ?

The Gluteal Region

11. The gluteal region is drained by ? veins. These empty into the ?

Answer 46

1. Underneath the deep fascia of the lower limb, accompanying the major arteries.

subcutaneous tissue. They eventually drain into the deep veins.

2. So the arterial pulsations aid the venous return
3. dorsal venous arch, anterior tibial vein
4. medial & lateral plantar, posterior tibial & fibular veins
5. medial malleolus
6. popliteal vein
7. adductor canal
8. femoral
9. profunda femoris
10. external iliac vein
11. inferior & superior gluteal, internal iliac vein

Question 47

Clinical relevance of DVT?

Answer 47

Question 48

The superficial veins of the lower limb run in the ? tissue. There are two major superficial veins – ?

Answer 48

subcutaneous,

the great saphenous vein, & the small saphenous vein.

Question 49

The Great Saphenous Vein

1. The great saphenous vein is formed by the ? of the foot, & the ? vein of the great toe. It ascends up the ? side of the leg, passing ? to the medial malleolus at the ankle, & ? to the medial condyle at the knee.
2. As the vein moves up the leg, it receives tributaries from other small superficial veins. The great saphenous vein terminates by draining into the femoral vein immediately ?
3. Clinical importance of the great saphenous vein?

Answer 49

1. dorsal venous arch, dorsal
2. medial, anteriorly, posteriorly
3. inferior to the inguinal ligament.
4. Surgically, the great saphenous vein can be harvested & used as a vessel in coronary artery bypasses.

Question 50

1. The small saphenous vein is formed by the ?
2. It moves up the ? side of the leg, passing ? to the lateral malleolus, along the ? border of the calcaneal tendon. It moves between the two heads of the ? muscle & empties into the ?

Answer 50

1. dorsal venous arch of the foot, & the dorsal vein of the little toe
2. posterior, posteriorly, lateral, gastrocnemius, popliteal vein in the popliteal fossa

Question 51

Clinical relevance: varicose veins

1. What are varicose veins?
2. In chronic varicose veins the pressure in the venous system rises. This damages the cells, causing blood to extrude into skin. Further complications can produce a ? of the surrounding tissue.
3. Varicose veins can be treated by;

Answer 51

In the lower limbs, venous blood flows from the skin to superficial veins, which drain into the deep veins.

Valves incompetent, blood flows back into the superficial veins, increased intra-luminal pressure, veins dilated & tortuous.

2. brown pigmentation & ulceration
3. • Surgical movement of the saphenous systems.
     - Reconstruction of valves.
     - Tying off the affected valves.

Question 52

Answer 52

Question 53

Lumbar plexus:

Sacral plexus:

nerve roots of origin, their motor functions & sensory distribution & describe the clinical effects of injury to them:

Answer 53

Ilioinguinal

Genitofemoral

Lateral cutaneous nerve of the thigh Femoral nerve

Obturator nerve

Superior gluteal nerve

Inferior gluteal nerve

Sciatic nerve and its divisions

Posterior femoral cutaneous nerve

Pudendal nerve

Question 54

Femoral nerve (prosection)

1. Nerve root
2. Anatomical course:

The nerve descends from the lumbar plexus in the abdomen through the ? muscle. The nerve then travels through the pelvis to approximately the ?. It then traverses behind the inguinal ligament into the thigh and splits into an ?

It passes through the ? lateral to the femoral vessels (enclosed within the femoral sheath) & gives off articular branches to the hip and knee joints.

The terminal cutaneous branch of the femoral nerve is the ? which continues, with the femoral artery and vein, through the adductor canal.

3. Motor function (4)
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 54

1. L2-L4
2. psoas major, mid-point of the inguinal ligament MPIL, anterior & posterior division

femoral triangle, saphenous nerve,

3. Anterior thigh

Hip Flexors:

Pectineus – adducts & flexes the thigh, assists with medial rotation of the thigh.

Iliacus – acts with psoas major & psoas minor (forming iliopsoas) to flex the thigh at the hip joint and stabilise the hip joint.

Sartorius – flexes, abducts & laterally rotates the thigh at the hip joint. Flexes the leg at the knee joint.

Knee Extensors

Quadriceps femoris (rectus femoris, vastus lateralis, vastus intermedius) – extends the leg at the knee joint. Rectus femoris also steadies the hip joint & assists iliopsoas in flexing the thigh.

3. Anterior cutaneous branches (femoral triangle) -> the skin on the anteromedial thigh.

saphenous nerve -> skin on the medial side of the leg and the foot.

5. Stripping of the Saphenous Vein

The saphenous vein is often stripped in individuals with problematic varicose veins. The long saphenous vein is accompanied in its course by the saphenous nerve. Damage to the saphenous nerve during this procedure can lead to pain, paraesthesia or complete loss of sensation the medial side of the lower leg

Femoral Nerve Block

Femoral nerve block (in combination with a sciatic nerve block) may be indicated in patients requiring lower limb surgery who cannot tolerate a general anaesthetic. A femoral nerve block can also be used as peri- & post-operative analgesia for patients with a fractured neck of femur who cannot tolerate particular analgesics.​

Question 55

Answer 55

Question 56

Answer 56

Question 57

Obturator nerve (prosection)

1. Nerve root
2. Anatomical course:

The obturator nerve is formed by the anterior divisions of the second, third and fourth lumbar nerves.

It descends through the fibres of the ? muscle & emerges from its medial border, running posteriorly to the ? & laterally along the pelvic wall to the ?. It then enters the thigh through the obturator canal & splits into ?

The anterior division descends between the adductor longus & adductor brevis muscles towards the femoral artery, giving off branches to the ?In rare cases it also gives off a branch to the ? muscle. It then pierces the fascia lata to become the ?

The posterior division descends through the ? muscle before passing anteriorly to ? & giving off branches to supply it.

3. Motor function (5)
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 57

1. Nerve roots: L2-L4
2. • psoas major, common iliac arteries, obturator foramen, anterior & posterior divisions.
     - adductor longus, adductor brevis & gracilis muscles. ,

pectineus, cutaneous branch of the obturator nerve

obturator externus, adductor magnus

3. medial compartment of the thigh except the hamstring part of the adductor magnus, which is innervated by the tibial nerve.

Adductor Longus – adducts thigh

Adductor Brevis – adducts thigh

Adductor Magnus – adductor part adducts and flexes thigh, hamstring part extends thigh

Gracilis – adducts thigh

Obturator Externus – laterally rotates thigh

4. The cutaneous branch of the obturator nerve supplies the skin of the middle part of the medial thigh.
5. Damage to the Obturator Nerve

Surgery to the pelvis or abdomen. Symptoms:

• numbness and paraesthesia on the medial aspect of the thigh
• weakness in adduction of the thigh.
• maybe posture & gait problems due to the loss of adduction.

Obturator Nerve Block

Use:

• management of pain after lower limb surgery
• chronic hip pain

The anaesthetic is injected inferior to the pubic tubercle & lateral to the tendon of the adductor longus muscle. The procedure can also be carried out under ultrasound guidance.

Question 58

Answer 58

Question 59

Answer 59

Question 60

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

x3

Question 61

Lateral Cutaneous Nerve of the Thigh

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 61

1. L2, L3
2. It enters the thigh at the lateral aspect of the inguinal ligament
3. None
4. Innervates the anterior and lateral thigh down to the level of the knee.

Question 62

Genitofemoral Nerve

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 62

1. L1, L2
2. After leaving the psoas major muscle, the genitofemoral nerve quickly divides into a genital branch, and a femoral branch.
3. The genital branch innervates the cremasteric muscle.
4. The genital branch innervates the skin of the anterior scrotum (in males) or the skin over mons pubis and labia majora (in females). The femoral branch innervates the skin on the upper anterior thigh.

Question 63

ilioinguinal nerve

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 63

1. L1
2. After innervating the muscles of the anterior abdominal wall, it passes through the superficial inguinal ring to innervate the skin of the genitalia and middle thigh.
3. Innervates the internal oblique & transversus abdominis.
4. Skin on the upper middle thigh. In males, it also supplies the skin over the root of the penis and anterior scrotum. In females, it supplies the skin over mons pubis and labia majora.

Question 64

Clinical Relevance –

Answer 64

Lumbosacral Plexopathy

Question 65

A lumbosacral plexopathy is a disorder affecting either the lumbar or sacral plexus of nerves. They are rare syndromes, caused by damage to the nerve bundles.

A plexopathy is suspected if the symptoms cannot be localised to a single nerve. Patients may complain of neuropathic pains, numbness or weakness and wasting of muscles.

One of the main causes of lumbosacral plexopathy is diabetic amyotrophy, also known as lumbosacral radioplexus neurophagy. In this condition, the high blood sugar levels damage the nerves. Idiopathic plexopathy is another cause, being the lumbosacral equivalent of Parsonage-Turner syndrome (which affects the brachial plexus). Tumours and other local invasions can cause the plexopathy due to the compression of the plexus.

Treatment depends on what is causing the symptoms. For tumours and space-occupying lesions, they should be removed if possible. For diabetic and idiopathic causes, treatment with high-dose corticosteroids can be useful.

Question 66

Sciatic nerve (prosection)

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 66

1. L4-S3
2. • derived lumbosacral plexus
     - leaves the pelvis & enters the gluteal region via greater sciatic foramen. It emerges inferiorly to the piriformis muscle and descends in an inferolateral direction.
     - gluteal region, it crosses the posterior surface of the superior gemellus, obturator internus, inferior gemellus & quadratus femoris muscles.
     - enters the posterior thigh by passing deep to the long head of the biceps femoris.

Within the posterior thigh, the nerve gives rise to branches to the hamstring muscles & adductor magnus.

When the sciatic nerve reaches the apex of the popliteal fossa, it terminates by bifurcating into the tibial & common fibular nerves.

Note: the sciatic nerve can be described as two individual nerves bundled together in the same connective tissue sheath – the tibial and common fibular nerves. These usually separate at the apex of the popliteal fossa, however in approximately 12% of people they separate as they leave the pelvis.

3. Although the sciatic nerve passes through the gluteal region, it does not innervate any muscles there. However, the sciatic nerve does directly innervate the muscles in the posterior compartment of the thigh, and the hamstring portion of the adductor magnus.

The sciatic nerve also indirectly innervates several other muscles, via its two terminal branches:

Tibial nerve – the muscles of the posterior leg (calf muscles), and some of the intrinsic muscles of the foot.

Common fibular nerve – the muscles of the anterior leg, lateral leg, and the remaining intrinsic foot muscles.

In total, the sciatic nerve innervates the muscles of the posterior thigh, entire leg & entire foot.

4. No direct sensory innervation via its terminal branches:

Tibial nerve – Innervates the posterolateral & anterolateral sides of the leg, & the plantar surface of the foot (the sole).

Common fibular nerve – Innervates the lateral leg & the dorsal surface of the foot.

5.

Question 67

Sciatic nerve

Clinical significance

Answer 67

Indicate the safe sites for intramuscular injection in the gluteal region LO

Question 68

Where do give intramuscular injections?

Answer 68

Question 69

Answer 69

Question 70

Answer 70

Question 71

Tibial nerve (prosection)

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution
5. Describe the clinical effects of injury to them

Answer 71

1. L4-S3
2. • branch of the sciatic nerve
     - at apex of the popliteal fossa.
     - gives branches to muscles in the superficial posterior compartment of the leg & the sural nerve (innervates the posterolateral aspect of the leg)
     - down the leg, posterior to the tibia. During its descent, it supplies the deep muscles of the posterior leg.
     - foot, posteriorly & inferiorly to the medial malleolus, tarsal tunnel. This tunnel is covered superiorly by the flexor retinaculum. - Within this tunnel, branches arise from the tibial nerve to supply cutaneous innervation to the heel

Immediately distal to the tarsal tunnel, the tibial nerve terminates by dividing into sensory branches, which innervate the sole of the foot.

3. The tibial nerve innervates all the muscles in the posterior compartment of the leg. They are divided into a deep & superficial compartment:

Deep

Popliteus – Laterally rotates the femur on the tibia to unlock the knee.

Flexor Hallucis Longus – Flexes the big toe and plantar flexes the ankle.

Flexor digitorum Longus – Flexes the other digits and plantar flexes the ankle.

Tibialis Posterior – Inverts the foot and plantar flexes the ankle.

Superficial

Plantaris – Plantar flexes the ankle.

Soleus – Plantar flexes the ankle.

Gastrocnemius – Plantar flexes the ankle & flexes the knee.

4. In the popliteal fossa, the tibial nerve gives off cutaneous branches. These combine with branches from the common fibular nerve to form the sural nerve. Which innervates the skin of the posterolateral side of the leg & the lateral side of the foot.

The tibial nerve also supplies all the sole of the foot via three branches:

• Medial calcaneal branches: These arise within the tarsal tunnel, & innervate the skin over the heel.
• Medial Plantar Nerve: Innervates the plantar surface of the medial three & a half digits, & the associated sole area.
• Lateral Plantar Nerve: Innervates the plantar surface of the lateral one & a half digits, & the associated sole area.
  5. Damage to the tibial nerve is rare, and is often a result of direct trauma, entrapment through narrow space or compression for long period of time. Damage results in loss of plantar flexion, loss of flexion of toes and weakened inversion (The tibialis anterior can still invert the foot).

Question 72

Answer 72

Question 73

Common fibular nerve (prosection)

1. Roots:
2. Anatomical course
3. Motor function
4. Sensory distribution

There are two cutaneous branches that arise directly from the common fibular nerve as it moves over the lateral head of the gastrocnemius.

In addition to these nerves, the terminal branches of the common fibular nerve also have a cutaneous function:

5. Describe the clinical effects of injury to them.
   - The common fibular nerve is most commonly damaged by a
   - The anatomical course of the common fibular nerve causes it to wrap round the neck of the fibular, and so any fractures of the fibular neck can cause ?

Patients with common fibular nerve damage will lose the ability to? I.e. How will they present?

Answer 73

1. L4 – S3
2. The nerve begins at the apex of the popliteal fossa, where the sciatic nerve bifurcates into the tibial and common fibular nerves.

The common fibular nerve follows the medial border of the biceps femoris, running in a lateral and inferior direction, over the lateral head of the gastrocnemius. At this point, the nerve gives rise to two cutaneous branches, which contribute to the innervation of the skin of the leg.

To enter the lateral compartment of the leg, the nerve wraps around the neck of the fibula, passing between the attachments of the fibularis longus muscle. Here, the common fibular nerve terminates by dividing into the superficial fibular & deep fibular nerves.

3.The common fibular nerve innervates the short head of the biceps femoris muscle (flex at the knee)

Superficial fibular nerve: Innervates the muscles of the lateral compartment of the leg; fibularis longus and brevis. These muscles act to evert the foot.

Deep fibular nerve: Innervates the muscles of the anterior compartment of the leg; tibialis anterior, extensor digitorum longus and extensor hallucis longus. These muscles act to dorsiflex the foot, and extend the digits. It also innervates some intrinsic muscles of the foot.

If the common fibular nerve is damaged, the patient may lose the ability to dorsiflex and evert the foot, and extend the digits.

4. Sural communicating nerve: This nerve combines with a branch of the tibial nerve to form the sural nerve. The sural nerve innervates the skin over the lower posterolateral leg.

Lateral sural cutaneous neve: Innervates the skin over the upper lateral leg.

Superficial fibular nerve: Innervates the skin of the anterolateral leg, & dorsum of the foot (except the skin between the first & second toes).

Deep fibular nerve: Innervates the skin between the first & second toes.

5. If the common fibular nerve is damaged, the patient may lose the ability to dorsiflex and evert the foot, & extend the digits.
   - Fracture of the fibula, or the use of a tight plaster cast.
   - nerve palsy
   - dorsiflex the foot at the ankle joint. Hence the foot will appear permanently plantarflexed – known as footdrop. They may also present with a characteristic gait, as a result of the footdrop
   - loss of sensation over the dorsum of the foot, and lateral side of the leg. Innervation is preserved on the medial side of the leg (supplied by the saphenous nerve, a branch of the femoral), and the heel and sole (supplied by the tibial nerve, a branch of the sciatic).

Question 74

Answer 74

Question 75

Answer 75

Question 76

The superficial fibula nerve

1. Anatomical Course
2. Motor Functions
3. Sensory functions
4. Clinical relevance

Answer 76

1. The superficial fibular nerve is a terminal branch of the common fibular nerve.

It arises at the neck of the fibula, descending between the fibularis muscles & the lateral side of the extensor digitorum longus. Here, it gives rise to motor branches, which supply the fibularis longus & brevis. The nerve continues its descent, with a purely cutaneous function, providing sensory innervation to the anterolateral aspect of the lower leg.

When the superficial fibular nerve reaches the lower third of the leg, it pierces the deep crural fascia & terminates by dividing into the medial & intermedial dorsal cutaneous nerves. These nerves enter the foot to innervate the majority of its dorsal surface.

It arises at the neck of the fibula, descending between the fibularis muscles & the lateral side of the extensor digitorum longus. Here, it gives rise to motor branches, which supply the fibularis longus & brevis. The nerve continues its descent, with a purely cutaneous function, providing sensory innervation to the anterolateral aspect of the lower leg.

When the superficial fibular nerve reaches the lower third of the leg, it pierces the deep crural fascia and terminates by dividing into the medial and intermedial dorsal cutaneous nerves. These nerves enter the foot to innervate the majority of its dorsal surface.

2. Fibularis longus & the fibularis brevis. These muscles form the lateral compartment of the lower leg.

They act to evert the foot, & thus act at the subtalar joint & plantarflexion (weak)

3. anterolateral leg, via cutaneous branches directly from the superficial fibular nerve.

Innervates the skin of the dorsum of the foot (except the webbed space between the hallux & the 2nd digit), via the medial & intermedial dorsal cutaneous nerves.

The dermatomes to which these areas correspond are L5 & S1.

4. Damage to the superficial fibular nerve; entrapment & direct damage (e.g from a comminuted fracture).

Question 77

Superficial Fibular Nerve Entrapment

1. Superficial peroneal nerve entrapment (also known as nerve compression) can cause ?
2. Entrapment frequently results from ?
3. Another cause of nerve entrapment occurs at the point where the ? Surgical decompression of the nerve therefore is used to provide relief from the symptoms & pain

Answer 77

1. pain & paraesthesia over the lower leg & dorsum of the foot
2. ankle sprains or twisting of the ankle, as this causes the nerve to stretch in the lower leg.
3. nerve exits the deep fascia of the leg, the nerve becoming compressed by this fascia.

Question 78

Direct Damage to the Superficial Fibular Nerve

1. The superficial fibular nerve may be damaged by ?
2. How is the patient likely to present?

Answer 78

1. fracture of the fibula, or by a perforating wound to the lateral side of the leg.
2. Loss of eversion & sensation from the Dorsum of the foot

As the muscles the superficial fibular nerve innervates are evertors, injury to the nerve may result in a loss of eversion. A loss of sensation over the majority of the dorsum of the foot and the anterolateral aspect of the lower leg could also result.

Question 79

Answer 79

Question 80

Answer 80

Question 81

Answer 81

Question 82

Deep fibular nerve

1. Anatomical location.
2. Motor function
3. Sensory function
4. Clinical relevance

Answer 82

1. Buzzwords: sciatic nerve, common fibular and the tibial nerves at the apex of the popliteal fossa,

neck of the fibula, moving anterolaterally, two terminal branches: the superficial & the deep fibular nerves.

The deep fibular nerve arises in the superolateral aspect of the leg, between the fibularis longus muscle & the neck of the fibula. The nerve moves from the lateral compartment to the anterior compartment of the leg. It then follows the course of the anterior tibial artery, in an inferomedial direction. Together, the two structures pass between the TA (tibialis anterior) & the EDL (extensor digitorum longus) in the superior portion of the leg, & between the TA (tibialis anterior) and the EHL (extensor hallucis longus) in the inferior leg.

The deep fibular nerve crosses the ankle joint, passing anterior to the distal tibia, & travels deep to the extensor retinaculum. It terminates in the dorsum of the foot, where it divides into:

A lateral branch: Supplies motor innervation to some of the intrinsic muscles of the foot,

A medial branch: A cutaneous nerve, innervating the skin between the 1st and 2nd toes.

Question 83

1. The sacral plexus is a network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb. It is located on the surface of the posterior pelvic wall, anterior to the ? muscle.
2. The plexus is formed by the anterior rami (divisions) of the sacral spinal nerves

Answer 83

1. piriformis
2. S1, S2, S3 and S4. It also receives contributions from the lumbar spinal nerves L4 and L5.

Question 84

The anterior rami of the S1-S4 spinal roots (and the lumbosacral trunk) divide into several cords. These cords then combine together to form the five major peripheral nerves of the sacral plexus.

Answer 84

Leave the pelvis via the greater sciatic foramen – these nerves enter the gluteal region of the lower limb, innervating the structures there.

Remain in the pelvis – these nerves innervate the pelvic muscles, organs and perineum.

Question 85

Superior Gluteal Nerve

1. Nerve roots
2. Anatomical course
3. Motor functions
4. Sensory distribution
5. Describe the clinical effects of injury to them:

Answer 85

1. L4, L5, S1
2. greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle. It is accompanied by the superior gluteal artery and vein for much of its course.
3. gluteus minimus, gluteus medius & tensor fascia lata.
4. None

Question 86

Inferior Gluteal Nerve

1. Nerve roots
2. Anatomical course
3. Motor functions
4. Sensory distribution
5. Describe the clinical effects of injury to them:

Answer 86

1. L5, S1,S2
2. Greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle.

It is accompanied by the inferior gluteal artery and vein for much of its course.

3. Innervates gluteus maximus.
4. None.

Question 87

Posterior femoral cutaneous nerve

1. Nerve roots
2. Anatomical course
3. Motor functions
4. Sensory distribution
5. Describe the clinical effects of injury to them:

Answer 87

1. S1, S2, S3
2. greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle. It descends deep to the gluteus maximus and runs down the back of the thigh to the knee.
3. None
4. Innervates the skin on the posterior surface of the thigh and leg. Also innervates the skin of the perineum.

Question 88

1. What is Lumbosacral Plexopathy?
2. Symptoms
3. One of the main causes of lumbosacral plexopathy is

Answer 88

They are rare syndromes, caused by damage to the nerve bundles

2. Symptoms cannot be localised to a single nerve. Neuropathic pains, numbness or weakness & wasting of muscles.
3. diabetic amyotrophy, also known as lumbosacral radioplexus neurophagy. In this condition, the high blood sugar levels damage the nerves. Idiopathic plexopathy is another cause, being the lumbosacral equivalent of Parsonage-Turner syndrome (which affects the brachial plexus). Tumours and other local invasions can cause the plexopathy due to the compression of the plexus.

Treatment depends on what is causing the symptoms. For tumours and space-occupying lesions, they should be removed if possible. For diabetic and idiopathic causes, treatment with high-dose corticosteroids can be useful.

Question 89

Describe the sensory function of the lower limb

Answer 89

Question 90

Describe the motor function of the lower limb

Answer 90

Question 91

The femoral canal is located in the anterior thigh, within the femoral triangle. It can be thought of as a rectangular shaped compartment.

It has four borders & an opening:

Answer 91

Medial border – Lacunar ligament.

Lateral border – Femoral vein.

Anterior border – Inguinal ligament.

Posterior border – Pectineal ligament, superior ramus of the pubic bone, and the pectineus muscle

The opening to the femoral canal is located at its superior border, known as the femoral ring. The femoral ring is closed by a connective tissue layer – the femoral septum. This septum is pierced by the lymphatic vessels exiting the canal.

Question 92

The femoral canal contains:

Answer 92

Lymphatic vessels – draining the deep inguinal lymph nodes.

Deep lymph node – the lacunar node.

Empty space.

Loose CT

The empty space allows distension of the adjacent femoral vein, so it can cope with increased venous return, or increased intra-abdominal pressure.

Question 93

Answer 93

Question 94

Answer 94

Question 95

Clinical relevance of femoral canal

Answer 95

Femoral hernia

Common site for bowel hernia

Question 96

1. A hernia is defined as ?
2. In a femoral hernia, part of the ? protrudes through the femoral ring.
3. It presents as a lump situated ? to the pubic tubercle. This type of herniation is more common in ?
4. The borders of the femoral canal are tough, & not particularly extendible. This can compress the hernia, interfering with its blood supply. A hernia with a compromised blood supply is known as a ?

Answer 96

1. where an internal part of the body pushes through a weakness in the muscle/ surrounding tissue wall
2. small intestine
3. inferolaterally
4. women, due to their wider bony pelvis.
5. strangulated hernia

Question 97

The adductor canal

1. The adductor canal is a narrow conical tunnel located in the thigh. It is 15cm long, extending from the ?

The canal serves as a passageway from structures moving between the ?

2. The adductor canal is bordered by muscular structures:
3. The adductor canal serves as a passageway from structures moving between the anterior thigh & posterior leg. It contains the ?
4. As the femoral artery & vein exit the canal, they become the ?

Answer 97

1. apex of the femoral triangle to the adductor hiatus of the adductor magnus

anterior thigh & posterior leg

2. Anterior: Sartorius.

Lateral: Vastus medialis

Posterior: Adductor longus and adductor magnus.

The apex of the adductor canal is marked by the adductor hiatus – a gap between the adductor & hamstring attachments of the adductor magnus.

3. femoral artery, femoral vein, nerve to the vastus medialis & the saphenous nerve (the largest cutaneous branch of the femoral nerve).
4. popliteal artery & vein respectively

Question 98

Clinical Relevance – Adductor Canal Block

1. In the adductor canal block, local anaesthetic is administered in the adductor canal to block the ?

The block can be used to provide ? for procedures involving the ?

2. The ? are used as anatomical landmarks to locate the saphenous nerve.

Answer 98

1. saphenous nerve in isolation, or together with the nerve to the vastus medialis (femoral nerve)
2. sensory anaesthesia, distal thigh and femur, knee and lower leg on the medial side.
3. sartorius & femoral artery

Question 99

Clinical Relevance – Adductor Canal Compression Syndrome

1. Adductor canal compression syndrome describes ?
2. A rare condition, it is usually caused by ?
3. It is most common in ?
4. Patients present with?

Answer 99

1. entrapment of the neurovascular bundle within the adductor canal.
2. hypertrophy of adjacent muscles such as vastus medialis.
3. young males
4. May present with claudication symptoms due to femoral artery occlusion (more common) or neurological symptoms due to entrapment of the saphenous nerve.

Claudication: a condition in which cramping pain in the leg is induced by exercise, typically caused by obstruction of the arteries.

Question 100

Answer 100

Question 101

Answer 101

Question 102

Popliteal fossa

1. The popliteal fossa is diamond shaped, with four borders. These borders are formed by the muscles in the posterior compartment of the leg & thigh:
2. The popliteal fossa also has a floor & a roof:
3. The popliteal fossa is the main conduit for neurovascular structures entering & leaving the leg. Its contents are (medial to lateral):
4. The tibial & common fibular nerves are the most ? of the contents of the popliteal fossa. They are both branches of the sciatic nerve. The common fibular nerve follows the ?
5. The ? pierces the popliteal fascia of the popliteal fossa to enter the diamond, & empty into the popliteal vein.
6. In the popliteal fossa, the deepest structure is the ?. It is a continuation of the femoral artery, & travels into the leg to supply it with blood.
7. Clinical relevance ?

Answer 102

1. Superomedial border: Semimembranosus

Superolateral border: Biceps femoris.

Inferomedial border: Medial head of the gastrocnemius.

Inferolateral border: Lateral head of the gastrocnemius & plantaris.

2. Floor: posterior surface of the knee joint capsule, & by the posterior surface of the femur.

Roof: popliteal fascia & skin. The popliteal fascia is continuous with the fascia lata of the leg.

3. Popliteal artery

Popliteal vein

Tibial nerve

Common fibular nerve

4. superficial
5. biceps femoris tendon, running along the lateral margin of the popliteal fossa.
6. small saphenous vein
7. popliteal artery
8. Swelling in the Popliteal Fossa

The appearance of a mass in the popliteal fossa has many differential diagnoses. The two major causes are baker’s cyst and aneurysm of the popliteal artery.

Question 103

Answer 103

Question 104

Bakers cyst

1. What is it?
2. The usually arise in conjunction with?
3. Whilst it usually self-resolves, what can happen?
4. An aneurysm is a dilation of an artery, which is greater than 50% of the normal diameter. The popliteal fascia (the roof of the popliteal fossa) is tough and non-extensible, and so an aneurysm of the popliteal artery has consequences for the other contents of the popliteal fossa.

The tibial nerve is particularly susceptible to compression from the popliteal artery. The major features of tibial nerve compression are:

Answer 104

1. inflammation and swelling of the semimembranosus bursa – a fluid filled sac found in the knee joint.
2. Arthritis of the knee (rheumatoid or osteoarthritis)
3. cyst can rupture & produce symptoms similar to deep vein thrombosis.

pain, swelling and tenderness in one of your legs (usually your calf)

a heavy ache in the affected area.

warm skin in the area of the clot.

red skin, particularly at the back of your leg below the knee.

4. Weakened or absent plantar flexion

Paraesthesia of the foot and posterolateral leg

An aneurysm of the popliteal artery can be detected by an obvious palpable pulsation in the popliteal fossa. An arterial bruit may be heard on auscultation.

Question 105

Other Causes of Bakers cyst

Answer 105

Rarer causes of a popliteal mass include deep vein thrombosis, adventitial cyst of the popliteal artery and various neoplasms (such as rhabdomyosarcoma).

Question 106

Answer 106

Question 107

Answer 107

Question 108

Fractures of the femur can be broadly classified into two main groups:

State which type of patients these fractures are common in.

If there is avascular necrosis

How the patients present

Answer 108

Question 109

1. Which direction of the shaft moving? Why?
2. On the posterior surface of the femoral shaft, there are roughened ridges of bone, these are called the?
3. Proximally, the medial border of the linea aspera becomes the ? The lateral border becomes the ?, where the ?
4. Distally, the linea aspera widens & forms the floor of the ?, the medial and lateral borders form the medial & lateral supracondylar lines. The medial supracondylar line stops at the ?, where the ?

Answer 109

1. The shaft descends in a slight medial direction. This brings the knees closer to the body’s centre of gravity, increasing stability.
2. linea aspera
3. pectineal line, gluteal tuberosity, gluteus maximus attaches

Distally, the linea aspera widens and forms the floor of the popliteal fossa, the medial and lateral borders form the medial and lateral supracondylar lines. The medial supracondylar line stops at the adductor tubercle, where the adductor magnus attaches.

4. popliteal fossa, adductor tubercle, adductor magnus attaches.

Question 110

Answer 110

Question 111

Clinical relevance of the femoral shaft?

Answer 111

Femoral shaft fracture

Question 112

Common or uncommon

Cause?

Pattern of fracture?

How to patients present?

What else must we check?

Answer 112

Question 113

Answer 113

Question 114

Answer 114

Question 115

The distal end is characterised by the presence of the medial and lateral condyles, which articulate with the tibia and patella, forming the knee joint.

1. Medial & lateral condyles – Rounded areas at the end of the femur. The posterior & inferior surfaces articulate with the ? of the knee, while the anterior surface articulates with the ?
2. Medial & lateral epicondyles – Bony elevations on the non-articular areas of the condyles. They are the area of attachment of some muscles & the collateral ligaments of the knee joint.

Intercondylar fossa – A depression found on the ? surface of the femur, it lies in between the two condyles. It contains two facets for attachment of internal knee ligaments.

3. Facet for attachment of the posterior cruciate ligament – Found on the ? wall of the intercondylar fossa, it is a large rounded flat face, where the posterior cruciate ligament of the knee attaches.
4. Facet for attachment of anterior cruciate ligament – Found on the ? wall of the intercondylar fossa, it is ? than the facet on the medial wall, and is where the anterior cruciate ligament of the knee attaches.

Answer 115

1. tibia & menisci, patella
2. posterior
3. medial
4. lateral, smaller

Question 116

Patella

1. The patella (knee-cap) is located at the front of the knee joint, within the ? groove of the femur. It attaches superiorly to the ?& inferiorly to the ?
2. It is classified as a ? type bone due to its position within the quadriceps tendon, & is the largest sesamoid bone in the body.

Answer 116

1. patellofemoral, quadriceps tendon, patellar ligament
2. sesamoid (a small independent bone or bony nodule developed in a tendon where it passes over an angular structure, typically in the hands and feet. The kneecap is a particularly large sesamoid bone

Question 117

1. The patella has a triangular shape, with anterior & posterior surfaces. The ? of the patella is situated inferiorly, & is connected to the tibial tuberosity by the patella ligament. The ? forms the superior aspect of the bone, & provides the attachment area for the quadriceps tendon.
2. The posterior surface of the patella articulates with the femur, & is marked by two facets:

Answer 117

1. apex, base,
2. Medial facet – articulates with the medial condyle of the femur.

Lateral facet – articulates with the lateral condyle of the femur.

Question 118

Answer 118

Question 119

Answer 119

Question 120

The patella has two main functions:

Answer 120

Leg extension – Enhances the leverage that the quadriceps tendon can exert on the femur, increasing the efficiency of the muscle.

Protection – Protects the anterior aspect of the knee joint from physical trauma.

Question 121

Clinical Relevance – Injury to the Patella

1. Patellar Dislocation

In a patellar dislocation, the patella bone is displaced out of the patellofemoral groove. It accounts for around 3% of knee injuries. Most dislocations occur ?, & are caused by ? These mechanisms of injury make patellar dislocation more common in individuals participating in sports such as: football, rugby and ice hockey.

2. Patellar Fracture

Patellar fractures usually result from ? They are more common in males, and in the 20-50 age range. If the patella fractures into fragments, they will usually separate; the proximal fragment displaced superiorly by the quadriceps tendon and the distal fragment pulled inferiorly by the patellar ligament.

Answer 121

1. laterally, high force impact on the patella or forceful sudden twisting of the knee,
2. direct trauma to the bone, or sudden contraction of the quadriceps muscle

Question 122

1. The tibia is the main bone of the leg, forming what is more commonly known as the shin. It expands at the proximal and distal ends, articulating at the knee and ankle joints respectively.

It is the second largest bone in the body, this is due to its function as a ?

2. At the proximal end, the tibia is widened by the medial & lateral condyles, aiding in weight bearing. The condyles form a flat surface, known as the ? This structure articulates with the femoral condyles to form the major articulation of the knee joint.
3. Located between the condyles is a region called the ? This area is the main site of attachment for the ligaments & the menisci of the knee joint. The tibial intercondylar tubercles fit into the ? of the femur.
4. On the anterior surface of the proximal tibia, inferior to the condyles, the ? is situated. This is where the patella ligament attaches

5.

Answer 122

1. weight bearing structure
2. tibial plateau
3. intercondylar eminence – this consists of two tubercles and a roughened area , intercondylar fossa
4. tibial tuberosity

5.

Question 123

Answer 123

Question 124

Shaft of the femur

1. Anterior border – The start of the anterior border is marked by the tibial tuberosity. It is palpable down the anterior surface of the leg as the shin. Here, the ? covering of the tibia is susceptible to damage, presenting clinically as bruising.
2. Posterior surface – This is marked by a ridge of bone called the ? It runs inferomedially, eventually blending with the medial border of the tibia. It is here where part of the soleus muscle originates
3. Lateral border – Also known as the interosseous border. This gives attachment to the interosseous membrane that binds the tibia and the fibula together.

Answer 124

1. periosteal
2. soleal line

Question 125

1. The distal end of the tibia, like the proximal, widens to help with weight bearing.

There is a bony projection continuing inferiorly on the medial side – this is called the ? It articulates with the tarsal bones to form part of the ankle joint. On the posterior surface of the tibia, there is a ? where the tibialis posterior muscle attaches.

2. Laterally, on the distal end, there is a notch, where the fibula is bound to the tibia. It is known as the ?

Answer 125

1. medial malleolus, groove
2. fibular notch

Question 126

Answer 126

Question 127

Answer 127

Question 128

Clinical Relevance: Fractures of the Tibia

1. Common or uncommon ?
2. Occur most frequently in the ?
3. If the fibula is not fractured, it supports the tibia, and displacement of the fragments is ?
4. The proximal end of the tibia is the site that is most vulnerable to damage, resulting usually from some traumatic accident e.g vehicular. The ? may be broken up in the fracture and it is not uncommon for there to be ?
5. At the ankle, the ? can be fractured. How?

Answer 128

1. Common
2. middle aged & elderly
3. minimal
4. condyles, injury to the ligaments of the knee
5. medial malleolus, This is caused by the ankle being twisted inwards (over-inversion) – the talus of the foot is forced against the medial malleolus, causing a spiral fracture.

Question 129

The fibula

1. The fibula, along with the tibia, makes up the bones of the leg. The fibula is found laterally to the tibia, and is much thinner. As it does not articulate with the femur at the knee joint, its main function is to act as an ?, and not as a weight bearer.
2. At the proximal end, the fibula has an enlarged head, which contains a facet for articulation with the ?
3. On the posterior & lateral surface of the fibular neck, the ? can be found.
4. The fibular shaft has three surfaces – anterior, lateral and posterior. The leg is split into three compartments, and each surface faces its respective compartment e.g anterior surface faces the anterior compartment of the leg.
5. Distally, the lateral surface continues inferiorly, and is called the ? The lateral malleolus is more prominent than the medial malleolus, and can be palpated at the ankle on the lateral side of the leg

Answer 129

1. attachment for muscles
2. lateral condyle of the tibia
3. common fibular nerve
4. lateral malleolus

Question 130

Clinical Relevance: Fractures of the Fibula

At the ankle, the lateral malleolus of the fibula is prone to fracture. There are two main ways in which this occurs & describe the fracture pattern.

Answer 130

Forced external rotation of the ankle. This force of the talus against the bone causes a spiral fracture of the lateral malleolus.

Less common way, by the foot being twisted outwards (called eversion). Again, the talus presses against the lateral malleolus, and causes a transverse fracture.

Question 131

The foot

1. The bones of the foot can be divided into three categories:
2. The proximal tarsal bones are the talus and the calcaneus. They form the bony framework around the proximal ankle and heel area.

The talus is the most superior of the tarsal bones. It has three articulations:

3. The main function of the talus is to transmit forces from the tibia to the heel bone (known as the calcaneus). Whilst numerous ? attach to the talus, it is not a site of ? attachment or origin.
4. The calcaneus lies underneath the talus, & has two articulations:
5. It is thick & sturdy, acting to transmit forces from the talus to the ground. The posterior aspect of the calcaneus is marked by ?, to which the Achilles tendon attaches.
6. The intermediate row of tarsal bones contains one bone, the navicular. It articulates with the ? posteriorly, the ? bones anteriorly, & the cuboid bone laterally.

On the plantar surface of the navicular, there is a tuberosity for the attachment of the ?

7. In the distal row, there are four tarsal bones – the cuboid and the three cuneiforms. These bones articulate with the metatarsals of the foot.

The cuboid is the most lateral bone in the distal row, articulating with the ? posteriorly, & ? anteriorly. As the name suggests, it is shaped like a cube. The inferior surface of the cuboid is marked by a groove for the ?

8. The three cuneiforms (lateral, intermediate & medial) are wedge shaped bones. They articulate with the ? posteriorly, & the metatarsals anteriorly. The shape of the bones helps form a ? across the foot.
9. Out of all the tarsal bones which ones are most frequently fractured?

Answer 131

The foot

1. The bones of the foot can be divided into three categories:
2. The proximal tarsal bones are the talus and the calcaneus. They form the bony framework around the proximal ankle and heel area.

The talus is the most superior of the tarsal bones. It has three articulations:

3. The main function of the talus is to transmit forces from the tibia to the heel bone (known as the calcaneus). Whilst numerous ? attach to the talus, it is not a site of ? attachment or origin.
4. The calcaneus lies underneath the talus, & has two articulations:
5. It is thick & sturdy, acting to transmit forces from the talus to the ground. The posterior aspect of the calcaneus is marked by ?, to which the Achilles tendon attaches.
6. The intermediate row of tarsal bones contains one bone, the navicular. It articulates with the ? posteriorly, the ? bones anteriorly, & the cuboid bone laterally.

On the plantar surface of the navicular, there is a tuberosity for the attachment of the ?
7. In the distal row, there are four tarsal bones – the cuboid and the three cuneiforms. These bones articulate with the metatarsals of the foot.
The cuboid is the most lateral bone in the distal row, articulating with the ? posteriorly, & ? anteriorly. As the name suggests, it is shaped like a cube. The inferior surface of the cuboid is marked by a groove for the ?
8. The three cuneiforms (lateral, intermediate & medial) are wedge shaped bones. They articulate with the ? posteriorly, & the metatarsals anteriorly. The shape of the bones helps form a ? across the foot.
9. Out of all the tarsal bones which ones are most frequently fractured?

Question 132

1. What two fractures are common at the talus?

What commonly causes these fractures?

Which one has avascular necrosis?

Answer 132

Question 133

How is the calcaneum commonly fractured?

Pattern of fracture?

How does it look on the x-ray?

Further problems?

Answer 133

Question 134

1. The metatarsals are located in the midfoot, between the tarsals and phalanges. They are numbered I-V (medial to lateral).

Each metatarsal has a similar structure. They consist of a distal head and proximal base, which are joined by a shaft of bone. They have three or four articulations:

2. Metatarsal fractures can occur by three mechanisms:
3. The phalanges are the bones of the toes. Most toes have three phalanges – proximal, intermediate and distal. The great toe only has proximal and distal phalanges.

Each phalanx consists of a body, a proximal extremity and a distal extremity.

Answer 134

1. Proximally: Tarsometatarsal joint – between the metatarsal bases & the cuneiforms or cuboid bones.

Laterally: Intermetatarsal joint(s) – between the metatarsal & the adjacent metatarsals.

Distally: Metatarsophalangeal joint – between the metatarsal head & the proximal phalanx.

3.

Question 135

Axial line is?

Answer 135

the line between two adjacent dermatomes that are not represented by immediately adjacent spinal levels

Question 136

• Upper limb outer layer of deep fascia is a

thick “stocking-like” membrane

• Particularly thick in the thigh and gluteal

region and is termed the ?

• Splits in the gluteal region
• anteriorly ->
• posteriorly ->
• Thickened laterally= ?
• Function ?

Answer 136

fascia lata

• anteriorly -> tensor fasciae latae muscle
• posteriorly -> gluteus maximus muscle iliotibial tract

Function: Holds leg in extension & stabilises hip joint with TFL & GM

Question 137

Answer 137

AP view

Lateral view (abduction & laterall rotation)

Question 138

Answer 138

So view

Lateral ( good for looking at the patella)

Axial (he kneecap runs in the groove)

Question 139

Functions of menisci

Answer 139

 Load transmission

 Shock absorbency

 stability

 Nutrition

Question 140

Question 141

Question 142

Locked knee

1. What is locking?
2. Most cases fall into:

Answer 142

1. Refers to when the leg gets stuck in one position, unable to bend or straighten
2. • true locking caused by a mechanical block where

something gets stuck inside the joint, preventing

movement – meniscal tear or loose body • Pseudo locking – pain + muscle spasm

(Both require surgery)

Question 143

Muscles in the anterior compartment of the thigh

1. The muscles in the anterior compartment of the thigh are innervated by the ?, & as a general rule, act to ?
2. There are three major muscles in the anterior thigh – the ?
3. In addition to these, the end of the ? muscle passes into the anterior compartment.

Answer 143

1. femoral nerve (L2-L4), extend the leg at the knee joint.
2. pectineus, sartorius & quadriceps femoris
3. iliopsoas

Question 144

Iliopsoas

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 144

1. Origin: psoas major - lumbar vertebrae

iliacus - iliac fossa of the pelvis.

2. Insert: lesser trochanter of the femur.
3. Innervation: psoas major is - anterior rami of L1-3

iliacus - is femoral nerve.

Actions: flexes & lateral rotation at the hip joint.

Question 145

Quadriceps Femoris

1. The quadriceps femoris consists of four individual muscles; three vastus muscles and the rectus femoris. They form the main bulk of the thigh, and collectively are one of the most powerful muscles in the body.

The muscles that form quadriceps femoris unite proximal to the knee, and distally attach to the patella via the ? The patella attaches to the tibia by the patella ligament. The quadriceps femoris is the main extensor of the knee.

Answer 145

1. patella tendon?? Quadriceps tendon

Question 146

Vastus Lateralis

1. Origin:
2. Insertion:
3. Innervation:
4. Action:

Answer 146

Origin: greater trochanter & the lateral lip of linea aspera.

Insert: tibial tuberosity via the patella ligament

Innervation: Femoral nerve.

Actions: Extends the knee joint & stabilises the patella.

Question 147

Vastus intermedius

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 147

1. Origin: Anterior & lateral surfaces of the femoral shaft
2. Innervation: Femoral nerve
3. Actions: Extends the knee joint & stabilises the patella.

Question 148

Vastus medialis

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 148

1. Origin: Intertrochanteric line & medial lip of the linea aspera.
2. Innervation: Femoral nerve.
3. Actions: Extends the knee joint & stabilises the patella, particularly due to its horizontal fibres at the distal end.

Question 149

Rectus Femoris

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 149

1. Ilium, just superior to the acetabulum.
2. Insertion attaches to the patella by the quadriceps femoris tendon.
3. Actions: flexes the leg at the hip joint, & extends at the knee joint.
4. Innervation: Femoral nerve.

Question 150

Sartorius

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 150

1. Origin: anterior superior iliac spine
2. Insert: superior, medial surface of the tibia.
3. Innervation: Femoral nerve
4. Actions: At the hip joint, it is a flexor, abductor & lateral rotator. At the knee joint, it is also a flexor.

Question 151

Pectineus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 151

• flat muscle
• base of the femoral triangle
• dual innervation -> transitional muscle between the anterior thigh & medial thigh compartments
  1. Origin: pectineal line on the anterior surface of the pelvis, 2. Insert: pectineal line on the posterior side of the femur, just inferior to the lesser trochanter.
  3. Innervation: Femoral nerve. May also receive a branch from the obturator nerve.
  4. Actions: Adduction & flexion at the hip joint.

Question 152

Pectineus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 152

• flat muscle
• base of the femoral triangle
• dual innervation -> transitional muscle between the anterior thigh & medial thigh compartments
  1. Origin: pectineal line on the anterior surface of the pelvis, 2. Insert: pectineal line on the posterior side of the femur, just inferior to the lesser trochanter.
  3. Innervation: Femoral nerve. May also receive a branch from the obturator nerve.
  4. Actions: Adduction & flexion at the hip joint.

Question 153

Clinical Relevance: Testing the Quadriceps Femoris

The quadriceps femoris muscle can be used to test the femoral nerve in cases of suspected nerve palsy.

This is performed by ?

Answer 153

positioning the patient supine, with the knee slightly flexed. The patient is asked to extend the leg (at the knee) against resistance. If the femoral nerve is damaged, contraction of the quadriceps femoris will be absent.

Question 154

Answer 154

Question 155

1. The muscles in the medial compartment of the thigh are collectively known as the hip adductors. There are five muscles in this group;
2. All the medial thigh muscles are innervated by the ? nerve, which arises from the ? Arterial supply is via the obturator artery.

Answer 155

1. gracilis, obturator externus, adductor brevis, adductor longus and adductor magnus.
2. obturator, lumbar plexus

3.

Question 156

Adductor magnus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 156

• posteriorly to the other muscles.
• Functionally, the muscle can be divided into two parts; the adductor part, & the hamstring part.
  1. Origin:

Adductor part – inferior rami of the pubis & the rami of ischium

Insert: linea aspera of the femur

Origin: Hamstring part – ischial tuberosity

Insert: adductor tubercle & medial supracondylar line of the femur.

3. Innervation: Adductor part is innervated by the obturator nerve (L2-L4), the hamstring part is innervated by the tibial nerve (L4-S3).
4. Actions: They both adduct the thigh. The adductor component also flexes the thigh, with the hamstring portion extending the thigh.

Question 157

Adductor Longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 157

• large, flat muscle.
• partially covers adductor brevis & magnus.
• medial border of the femoral triangle. (Medial part of the muscle)
  1. Origin: pubis, & expands into a fan shape

Insert: broadly to the linea aspera of the femur

3. Innervation: Obturator nerve (L2-L4)
4. Actions: Adduction & medial rotation of the thigh.

Question 158

Adductor brevis

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 158

• short muscle, lying underneath the adductor longus.
• Between the anterior & posterior divisions of the obturator nerve. (anatomical landmark)
  1. Origin: body of pubis & inferior pubic rami
  2. Insert: linea aspera on the posterior surface of the femur, proximal to the adductor longus
  3. Innervation: Obturator nerve (L2-L4)
  4. Actions: Adduction of the thigh

Question 159

Obturator Externus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 159

1. Origin: membrane of the obturator foramen, & adjacent bone. It passes under the neck of femur,
2. Inserts: posterior aspect of the greater trochanter
3. Innervation: Obturator nerve (L2-L4)
4. Actions: Laterally rotates the thigh.

Question 160

Gracilis

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 160

• sometimes transplanted into the hand or forearm to replace a damaged muscle
  1. Origin: inferior rami of the pubis, & the body of the pubis. (Descending almost vertically down the leg)
  3. Insert: medial surface of the tibia, between the tendons of the sartorius (anteriorly) & the semitendinosus (posteriorly).
  3. Innervation: Obturator nerve (L2-L4).
  4. Actions: Adduction of the thigh at the hip, and flexion of the leg at the knee.

Question 161

Clinical Relevance: Injury to the Adductor Muscles

1. Strain of the adductor muscles is the underlying cause of what is colloquially known as a ‘?‘. The ? part of the muscle is most commonly affected, tearing near their bony attachments in the pelvis.
2. Groin injuries usually occur in sports that require explosive movements or extreme stretching. Treatment of any muscle strain should utilise the RICE protocol – ?

Answer 161

1. groin strain, proximal
2. rest, ice, compression & elevation.

Question 162

Answer 162

Question 163

Answer 163

Question 164

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 164

Question 165

Muscles in the posterior compartment of the thigh

1. The muscles in the posterior compartment of the thigh are collectively known as the ? They consist of the ?, which form prominent tendons medially and laterally at the back of the knee.
2. As group, these muscles act to ? They are innervated by the ?

Answer 165

1. hamstrings, biceps femoris, semitendinosus & semimembranosus
2. extend at the hip & flex at the knee, sciatic nerve (L4-S3)

Question 166

Biceps femoris

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 166

Biceps femoris muscle has two heads – a long head and a short head.

It is the most lateral of the muscles in the posterior thigh – the common tendon of the two heads can be felt laterally at the posterior knee.

Origin: long head - ischial tuberosity

short head - linea aspera on posterior surface of the femur. 2. Insert: head of the fibula

3. Innervation: Long head - tibial part of the sciatic nerve, short head - common fibular part of the sciatic nerve.
4. Actions: flexion at the knee. It also extends the leg at the hip, and laterally rotates at the hip & knee.

Question 167

Semitendinosus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 167

• medially to the biceps femoris, & covers the majority of the semimembranosus
  1. Origin: ischial tuberosity of the pelvis
  2. Insert: medial surface of the tibia
  3. Innervation: Tibial part of the sciatic nerve
  4. Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint & the leg at the knee joint.

Question 168

Semimembranosus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 168

• flattened & broad muscle
• underneath the semitendinosus.
  1. Origin: Ischial tuberosity, (superiorly to semitendinosus & biceps femoris)
  2. Insert: Medial tibial condyle
  3. Innervation: Tibial part of the sciatic nerve.
  4. Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint & the leg at the knee joint.

Question 169

Clinical Relevance: Damage to the Hamstrings

1. Muscle Strain

A hamstring strain refers to ? 2. They are often seen ?

3. Damage to the muscle fibres is likely to rupture the surrounding blood vessels – producing a ?

Treatment of any muscle strain should utilise the RICE protocol – rest, ice, compression and elevation.

4. Avulsion Fracture of the Ischial Tuberosity

An avulsion fracture occurs when a ?

In an avulsion fracture of the ischial tuberosity, the hamstring tendons ‘tear off’ a piece of the ischial tuberosity. Such an injury usually occurs in ?

Answer 169

1. excessive stretch / tearing of the muscle fibres.
2. athletes involved in running or kicking sports
3. haematoma (a collection of blood). The haematoma is contained by the overlying fascia lata
4. fragment of bone breaks away from the main body of bone.

sports that require rapid contraction and relaxation of the muscles – such as sprinting, football and hurdling.

Question 170

1. Fascia:
2. There are three general classifications of fascia:
3. The fascia lata is a deep fascial investment of the whole thigh musculature & is analogous to a strong, extensible & elasticated stocking. It begins most proximally around the ? & ends most distally to the ?
4. The width of the fascia lata varies considerably at different regions of the thigh. It is thickest along the ? aspect of the thigh, originating from the fascial condensations from ?, & also from around the knee where the fascia receives reinforcing fibres from tendons. The fascial investment is thinnest where it covers the ?
5. The deepest aspect of fascia lata gives rise to ?
6. This divides the thigh musculature into three compartments; ?The lateral intermuscular septum is the strongest of the three due to reinforcement from the, whereas the other two septa are proportionately weaker.
7. An ovoid hiatus is present in the fascia lata just inferior to the inguinal ligament known as the ? This gap serves as an entry point for efferent lymphatic vessels & the great saphenous vein, draining into superficial inguinal lymph nodes & the femoral vein respectively. A covering of membranous tissue (the cribriform fascia) covers the hiatus which develops inferomedially from a sharp margin of the gap (the falciform margin).

Answer 170

1. Band of fibrous tissue lying deep to the skin that lines, invests & separates structures within the body.
2. Superficial fascia: blends with the reticular layer beneath the dermis.

Deep fascia: envelopes muscles, bones and neurovascular structures.

Visceral fascia: provides membranous investments that suspend organs within their cavities.

3. iliac crest & inguinal ligament, bony prominences of the tibia; where it continues to become the deep fascia of the leg (the crural fascia).
4. superolateral, gluteus maximus & medius, adductor muscles of the medial thigh
5. three intermuscular septa that attach centrally to the femur.
6. anterior, medial & lateral, iliotibial tract
7. saphenous opening

Question 171

Answer 171

Question 172

Answer 172

Question 173

The Iliotibial Tract (ITT)

1. The iliotibial tract is a ?, which is strengthened posteriorly by fibres from the ?. 2. It is located laterally in the thigh, extending from the ?
2. The ITT has three main functions:

Answer 173

1. longitudinal thickening of the fascia lata, gluteus maximus
2. iliac tubercle to the lateral tibial condyle
3. Movement: acts as an extensor, abductor & lateral rotator of the hip, with an additional role in providing lateral stabilisation to the knee joint.

Compartmentalisation: The deepest aspect of ITT extends centrally to form the lateral intermuscular septum of the thigh & attaches to the femur.

Muscular sheath – forms a sheath for the tensor fascia lata muscle.

Question 174

1. The tensor fascia lata is a gluteal muscle that acts as a ? of the hip. Its nomenclature however, is derived from its additional role in ?
2. Origin:
3. Insertion:
4. When stimulated, the tensor fasciae lata ? especially when the ?
5. The property of TFL tightening the fascia lata is analogous to hoisting an elastic stocking up the thigh. When the fascia lata is pulled taut, it forces ?
6. An additional property of tensing the fascia lata is that it ?

Answer 174

1. flexor, abductor & internal rotator
2. tensing the fascia lata
3. iliac crest descends down the superolateral thigh. At the junction of the middle & upper thirds of the thigh, it
4. Inserts: anterior aspect of the iliotibial tract
5. tautens the iliotibial band and braces the knee,opposite foot is lifted.
6. muscle groups closer together within their intermuscular septa towards the femur. This action centralises muscle weight and limits outward expansion, which in turn reduces the overall force required for movement at the hip joint.
7. makes muscle contraction more efficient in compressing deep veins. This ensures adequate venous return to the heart from the lower limbs.

Question 175

Proximal

1. The fascia lata forms multiple superior attachments around the pelvis & hip region:
2. The fascia lata is also continuous with regions of deep and superficial fascia at its superior aspect. The deep iliac fascia descends from the thoracic region at the diaphragm, covers the entire iliacus and psoas regions and blends with the fascia lata superiorly. Superficial fascia from the inferior abdominal wall (Scarpa’s fascia) and perineal region both blend with the fascia lata just below the inguinal ligament.

Answer 175

1. Posterior: sacrum & coccyx

Lateral: iliac crest

Anterior: inguinal ligament, superior pubic rami

Medial: inferior ischiopubic rami, ischial tuberosity, sacrotuberous ligament

2.

Question 176

Answer 176

Question 177

Lateral

1. The lateral thickening of fascia lata forms the ? & receives tendon insertions superiorly from ?
2. The widened band of fibres descends the lateral thigh & attaches to the ?on the anterolateral (Gerdy) tubercle.

Inferior

3. The fascia lata ends at the knee joint where it then becomes the deep fascia of the leg (the Crural fascia). Attachments are made at bony prominences around the knee including the ?

Central

4. The deep aspect of fascia lata produces three intermuscular septa which attach centrally to the femur. The lateral septum joins to the lateral lip of the linea aspera & the medial & anterior septa attach to the medial lip. These attachments then continue along the whole length of the femur to include the supracondylar lines.

Answer 177

1. iliotibial tract, gluteus maximus & tensor fascia lata
2. lateral tibial condyle
3. femoral & tibial condyles, patella, head of fibula & the tibial tuberosity.

Question 178

Clinical Significance: Transplantation

1.

Answer 178

Dermatofasciotomy and debridement can leave large wound sites that require post-operative grafts to facilitate tissue regeneration and healing. The fascia lata graft is a popular choice as the iliotibial tract provides a particularly high concentration of connective tissue fibres, and can be surgically harvested whilst leaving the majority of fibres intact.

Novel developments in transplantation have also shown success with using fascia lata in reconstructive surgery. Advances have included:

Heart valve replacements

Eyelid reparations

Dura mater repair

Urinary incontinence treatment (fascia lata sling)

The main advantage of using fascia lata opposed to an artificial product (e.g. alloplastic silicone sheets) is that it is well vascularised upon transplantation, whereas the later requires microvascular anastomosis.

Question 179

1. The bony pelvis consists of the two hip bones (innominate or pelvic bones), sacrum and coccyx. There are four articulations within the pelvis:

Answer 179

1. Sacroiliac Joints (x2) – Between the ilium of the hip bones, and the sacrum

Sacrococcygeal symphysis – Between the sacrum & the coccyx.

Pubic symphysis – Between the pubis bodies of the two hip bones.

Question 180

1. The hip bone is made up of the three parts – the? Prior to puberty, the triradiate cartilage separates these constituents. At the age of 15-17, the three parts begin to fuse.

Their fusion forms a cup-shaped socket known as the ?, which becomes complete at 20-25 years of age. The head of the femur articulates with the acetabulum to form the hip joint.

2. The superior part of the hip bone is formed by the ilium, the widest and largest of the three parts. The body of the ilium forms the superior part of the acetabulum. Immediately above the acetabulum, the ilium expands to form the wing (or ala).

The wing of the ilium has two surfaces. The inner surface is concave, and known as the ?, providing origin to the iliacus muscle. The external surface is convex, and provides attachments to the gluteal muscles. Hence it is known as the ?

3. The superior margin of the wing is thickened, forming the ? It extends from the ?
4. Muscles attaching to the Ilium: –

Answer 180

1. ilium, pubis & ischium,

acetabulum

2. iliac fossa, gluteal surface
3. iliac crest, anterior superior iliac spine to the posterior superior iliac spine.
4. Gluteal muscles attach to the external surface of the Ilium at the anterior, posterior & inferior gluteal lines.

The iliacus muscle attaches medially at the iliac fossa.

Question 181

ASIS clinical significance

Answer 181

Question 182

1. The pubis is the most anterior portion of the hip bone. It consists of a ?
2. The body is located medially, articulating with its opposite pubic body, at the ?
3. The superior ramus extends laterally from the body, forming part of the ? The inferior ramus projects towards, & joins the ischium.
4. Together, the two rami enclose part of the ?, through which the ? pass through to reach the lower limb.

Answer 182

1. body & superior & inferior rami (branches).
2. pubic symphysis
3. acetabulum
4. obturator foramen
5. obturator nerve, artery & vein

Question 183

1. The posterioinferior part of the hip bone is formed by the ischium. Much like the pubis, it is composed of a ?
2. The inferior ischial ramus combines with the inferior pubic ramus forming the ? which encloses part of the obturator foramen. The posterorinferior aspect of the ischium forms the ? & when sitting, it is these tuberosities on which our body weight falls.

On the posterior aspect of the ischium there is an indentation known as the ?, with the ischial spine at its most inferior edge.

3. Two important ligaments attach to the ischium:

Answer 183

1. body, an inferior and a superior ramus.
2. ischiopubic ramus,

ischial tuberosities, greater sciatic notch,

3. The sacrospinous ligament runs from the ischial spine to the sacrum, thus creating the greater sciatic foramen through which lower limb neurovasculature (including the sciatic nerve) transcends.

The sacrotuberous ligament runs from the sacrum to the ischial tuberosity, forming the lesser sciatic foramen.

Question 184

1. There are two common ways of fracturing the pelvic bones:
2. Fractures often occur at the weaker points of the bones. These are the?
3. A common complication of pelvic fractures is soft tissue injury. In particular, the bladder and urethra are at high risk of damage.

Answer 184

1. Direct trauma to the pelvic bones, for example from a vehicular accident.

Forces transmitted from the lower limb, for example a heavy fall on the feet.

2. pubic rami, the acetabulum or in the region of the sacroiliac joint.

3.

Question 185

Answer 185

Question 186

Answer 186

Question 187

Answer 187

Question 188

Answer 188

Question 189

The Superficial Muscles

The superficial muscles in the gluteal region consist of the three glutei and the tensor fascia lata. They mainly act to ? the lower limb at the hip joint.

Answer 189

abduct & extend

Question 190

Gluteus maximus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 190

1. Gluteal (posterior) surface of the ilium, sacrum & coccyx. It slopes across the buttock at a 45 degree angle,
2. Inserts: iliotibial tract & the gluteal tuberosity of the femur.
3. Innervation: Inferior gluteal nerve.
4. Actions: It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.

Question 191

Gluteus medius

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 191

fan-shaped

1. Origin: gluteal surface of the ilium
2. Inserts: lateral surface of the greater trochanter.
3. Actions: Abducts & medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb. (Note: the posterior fibres of the gluteus medius are also thought to produce a small amount of lateral rotation).
4. Innervation: Superior gluteal nerve

Question 192

Gluteus Minimus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 192

1. Origin: ilium & converges to form a tendon
2. Insert: anterior side of the greater trochanter
3. Innervation: Superior gluteal nerve
4. Actions: Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb.

Question 193

Tensor Fascia Lata

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 193

• tighten the fascia lata, and so abducts and medially rotates the lower limb.
  1. Origin: the anterior iliac crest, attaching to the anterior superior iliac spine (ASIS).
  2. Inserts: iliotibial tract, which itself attaches to the lateral condyle of the tibia.
  3. Innervation: Superior gluteal nerve
  4. Actions: Assists the gluteus medius and minimus in abduction & medial rotation of the lower limb. It also plays a supportive role in the gait cycle.

Question 194

LO what happens when you get superior gluteal nerve damage

Answer 194

Question 195

Piriformis

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 195

• most superior of the deep muscles.
  1. Origin: anterior surface of the sacrum. (It then travels infero-laterally, through the greater sciatic foramen,
  2. Insert: Greater trochanter of the femur.
  3. Innervation: Nerve to piriformis
  4. Actions: Lateral rotation & abduction.

Question 196

Obturator internus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 196

1. Origin: pubis & ischium at the obturator foramen. It travels through the lesser sciatic foramen
2. Inserts: greater trochanter of the femur.
3. Innervation: Nerve to obturator internus

Actions: Lateral rotation & abduction

Question 197

The Gemelli – Superior & Inferior

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 197

• narrow & triangular muscles. They are separated by the obturator internus tendon.
  1. Origin: superior gemellus - ischial spine

inferior - ischial tuberosity

2. Insert - greater trochanter of the femur
3. Innervation: The superior gemellus -nerve to obturator internus

inferior gemellus - nerve to quadratus femoris.

4. Actions: Lateral rotation & abduction

Question 198

Quadratus Femoris

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 198

• flat, square-shaped muscle. It is the most inferior of the deep gluteal muscles, located below the gemelli and obturator internus.
  1. Origin: ischial tuberosity
  2. Insert: quadrate tuberosity on the intertrochanteric crest
  3. Innervation: Nerve to quadratus femoris.
  4. Actions: Lateral rotation.

Question 199

Clinical Relevance: Landmark of the Gluteal Region

1. The piriformis is an important anatomical landmark in the gluteal region.

As the muscle travels through the ?, it effectively divides the gluteal region into an inferior and superior part. This division determines the name of the vessels and nerves that supply the area. The superior gluteal nerve and vessels emerge into the gluteal region superiorly to the piriformis (and vice versa for the inferior gluteal nerve).

In addition, the piriformis can be used to locate the sciatic nerve (a major peripheral nerve of the lower limb). The sciatic nerve enters the gluteal region directly inferior to the piriformis, and is visible as a flat band, approximately 2cm wide.

Question 200

Clinical Relevance: Landmark of the Gluteal Region

1. The piriformis is an important anatomical landmark in the gluteal region.

As the muscle travels through the ?, it effectively divides the gluteal region into an inferior and superior part. This division determines the name of the vessels and nerves that supply the area. The superior gluteal nerve and vessels emerge into the gluteal region superiorly to the piriformis (and vice versa for the inferior gluteal nerve).

In addition, the piriformis can be used to locate the sciatic nerve (a major peripheral nerve of the lower limb). The sciatic nerve enters the gluteal region directly inferior to the piriformis, and is visible as a flat band, approximately 2cm wide.

Answer 200

1. greater sciatic foramen

Question 201

1. There are four muscles in the anterior compartment of the leg;
2. Collectively, they act to ? the foot at the ankle joint.
3. The extensor digitorum longus & extensor hallucis longus also ? the toes.
4. The muscles in this compartment are innervated by the ?, and blood is supplied via the anterior tibial artery.

Answer 201

1. tibialis anterior, extensor digitorum longus, extensor hallucis longus & fibularis tertius.
2. dorsiflex & invert
3. extend
4. deep fibular nerve (L4-L5)

Question 202

Tibialis anterior

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 202

• strongest dorsiflexor of the foot
• To test the power of the tibialis anterior, the patient can be asked to stand on their heels
  1. Origin: lateral surface of the tibia
  2. Insert: medial cuneiform & the base of metatarsal I.
  3. Innervation: Deep fibular nerve
  4. Actions: Dorsiflexion & inversion of the foot

Question 203

Extensor digitorum longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 203

• lateral & deep to the tibialis anterior
• tendons of the EDL can be palpated on the dorsal surface of the foot.
  1. Origin: lateral condyle of the tibia & the medial surface of the fibula.
  2. Insert: INSERTION: Bases and dorsal aponeuroses of the lateral four digits via the extensor expansion.
  3. Innervation: Deep fibular nerve
  4. Actions: Extension of the lateral four toes, & dorsiflexion of the foot

Question 204

Extensor hallucis longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 204

• deep to the EDL & TA
  1. Origin: medial surface of the fibular shaft (The tendon crosses anterior to the ankle joint & attaches to the base of the distal phalanx of the great toe)
  3. Innervation: Deep fibular nerve
  4. Action: Extension of the great toe & dorsiflexion of the foot.

Question 205

Fibularis Tertius

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 205

• inferior part of the EDL
• not present in all individuals & is considered by some texts as a part of the extensor digitorum longus.
  1. Origin: extensor digitorum longus from the medial surface of the fibula
  2. Insertion: metatarsal V
  3. Innervation: Deep fibular nerve
  4. Actions: Eversion & dorsiflexion of the foot

Question 206

Clinical Relevance: Footdrop

1. Footdrop is a clinical sign indicating ?
2. It is most commonly seen when the ? is damaged.
3. In footdrop, the muscles in the anterior compartment are paralysed. The unopposed pull of the plantarflexor muscles (found in the posterior leg) produces permanent plantarflexion. This can interfere with walking – as the affected limb can drag along the ground. To circumvent this, the patient can ?

Answer 206

1. paralysis (loss of the ability to move one or more muscles) of the muscles in the anterior compartment of the leg.
2. common fibular nerve (from which the deep fibular nerve arises)
3. flick the foot outwards while walking – known as an ‘eversion flick‘.

Question 207

Answer 207

Question 208

Answer 208

Question 209

1. There are two muscles in the lateral compartment of the leg; the ?
2. The common function of the muscles is ?
3. They are both innervated by the ?

Note: From the anatomical position, only a few degrees of eversion are possible. In reality, the job of these muscles is to ‘fix’ the medial margin of the foot during running, and prevent excessive inversion.

Answer 209

1. fibularis longus and brevis (also known as peroneal longus & brevis)
2. eversion
3. superficial fibular nerve

Question 210

Fibularis longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 210

1. Origin: superior & lateral surface of the fibula and the lateral tibial condyle.

(Tendon descends into the foot, posterior to the lateral malleolus. The tendon crosses under the foot)

2. Inserts: medial cuneiform & base of metatarsal I.
3. Innervation: Superficial fibular (peroneal) nerve, L4-S1.
4. Actions: Eversion and plantarflexion of the foot. Also supports the lateral & transverse arches of the foot.

Question 211

Fibularis brevis

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 211

• deeper & shorter than the fibularis longus.
  1. inferolateral surface of the fibular shaft. (The muscle belly forms a tendon, which descends with the fibularis longus into the foot. It travels posteriorly to the lateral malleolus, passing over the calcaneus & the cuboidal bones.
  2. Insert: tubercle on metatarsal V
  3. Innervation: Superficial fibular (peroneal) nerve, L4-S1
  4. Actions: Eversion of the foot

Question 212

Question 213

Clinical Relevance: Locating the Common Fibular Nerve

The common fibular nerve can be a difficult structure to identify. However, it can be located using the fibularis longus as an anatomical landmark. How?

Answer 213

There is a small space between the parts of the fibularis longus that originate from the head of the fibula, and the neck of the fibula. The common fibular nerve passes through this gap, and is easily identified.

After passing through the gap, the nerve terminates by bifurcating into two terminal branches; the deep and superficial fibular nerve

Question 214

The posterior compartment of the leg contains seven muscles, organised into two layers – superficial and deep. The two layers are separated by a band of fascia.

1. The posterior leg is the largest of the three compartments. Collectively, the muscles in this area ? the foot.
2. They are innervated by the ?, a terminal branch of the sciatic nerve.

Answer 214

1. plantarflex & invert
2. tibial nerve

Question 215

1. The superficial muscles form the characteristic ‘calf’ shape of the posterior leg. They all insert into the ? of the foot (the heel bone), via the calcaneal tendon. The calcaneal reflex tests spinal roots S1-S2.
2. To minimise friction during movement, there are two bursae (fluid filled sacs) associated with the calcaneal tendon:

Answer 215

1. calcaneus
2. Subcutaneous calcaneal bursa – lies between the skin and the calcaneal tendon.

Deep bursa of the calcaneal tendon – lies between the tendon and the calcaneus.

Question 216

Gastrocnemius

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 216

Two heads – medial & lateral, which converge to form a single muscle belly.

1. Origin: lateral head - lateral femoral condyle

medial head - medial condyle

2. Insert: calcaneus
3. Innervation: Tibial nerve
4. Actions: plantarflexion & flexion of knee joint

Question 217

Plantaris

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 217

• absent in 10% of people.
  1. Origin: lateral supracondylar line of the femur. (descends medially, condensing into a tendon that runs down the leg, between the gastrocnemius & soleus. The tendon blends with the calcaneal tendon.)
  3. Innervation: Tibial nerve
  4. Actions: plantarflexion & knee flexion

Question 218

Soleus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 218

1. Origin: soleal line of the tibia & proximal fibular area
2. Innervation: Tibial Nerve
3. Actions: Plantarflexes the foot at the ankle joint.

Question 219

Clinical significance of the calcaneul tendon

Answer 219

Question 220

1. There are four muscles in the deep compartment of the posterior leg. One muscle, the ?, acts only on the knee joint. The remaining three muscles (?) act on the ankle and foot.

Answer 220

1. popliteus

tibialis posterior, flexor hallucis longus and flexor digitorum longus

Question 221

Popliteus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 221

• base of the popliteal fossa
• popliteus bursa = between the popliteal tendon & posterior surface of the knee joint
  1. Origin: posterior surface of the proximal tibia. (The fibres pass upwards & laterally)
  2. Lateral condyle of the femur & the lateral meniscus of the knee joint.
  3. Innervation: Tibial nerve
  4. Actions: Laterally rotates the femur on the tibia – ‘unlocking’ the knee joint so that flexion can occur.

Question 222

Tibialis posterior

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 222

ORIGIN: Interosseous membrane & the adjacent margins of the tibia & fibula.

INSERTION: Navicular tuberosity; the medial cuneiform; the bases of the 2nd-4th metatarsal bones.

ACTION: Plantar flexion of the talocrural joint and inversion of the subtalar joint.

NERVE SUPPLY: Tibial nerve (L4-L5).

Question 223

Flexor digitorum longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 223

ORIGIN: Middle third of the posterior surface of the tibia.

INSERTION: Bases of the distal phalanges of the 2nd-5th digits.

ACTION: Plantar flexion of the talocrural joint; inversion of the subtalar joint; plantar flexion of the metatarsophalangeal and interphalangeal joints of the 2nd-5th digits.

NERVE SUPPLY: Tibial nerve (L5-S2).

Question 224

Flexor hallucis longus

1. Origin
2. Insertion
3. Innervation
4. Action

Answer 224

1. ORIGIN: Interosseous membrane & the distal two-thirds of the posterior surface of the fibula.
2. INSERTION: Base of the distal phalanx of the 1st toe.

ACTION: Plantar flexion of the talocrural joint; inversion of the subtalar joint; plantar flexion of the metatarsophalangeal and interphalangeal joints.

NERVE SUPPLY: Tibial nerve.