Gluteal region, hip and thigh

Question 1

What are the 4 regions of the lower limb?

Answer 1

• Gluteal region
• Thigh region -> from hip joint to knee joint
• Leg region -> leg joint to the ankle joint
• Foot region -> distal to ankle joint

Question 2

What does the lower limb require? How does this compare to the upper limb?

What are the 4 main functions of the lower limb?

Answer 2

• The lower limb requires strength and stability in preference to range of movement
• Lower limb –> low mobility, high stability
• The upper limb –> High mobility, less stability

4 main functions of lower limb:

• Support body weight
• Maintain upright posture
• Locomotion (gait)
• Accomodate shock loading

Question 3

What 4 phases are there of walking?

What is the last thing to leave the floor before you enter swing phase of walking?

Answer 3

• Heel strike
• Support
• Toe off
• Carry through / swing phase
• Last thing to leave the ground before the swing phase is your Hallux (big toe), able to propel whole body forward.

Question 4

What shape is the pelvic girdle?

What forms it?

What does it allow?

What can cause fracture?

Answer 4

• Pelvic girdle is a basin shaped rigid ring of bone that is partly formed by the sacrum (axial skeleton) and two pelvic bones (appendicular skeleton).
• Enables distribution of weight of the axial body to the lower limbs
• Enables locomotion and standing
• Fracture of the pelvic girdle can be caused by HIGH FORCE TRAUMA
  
  • Force transmission mostly via compression

Question 5

What type of joint forms the hip joint?

How does this differ to the shoulder joint?

What is required to stabilise it?

What type of joint exists at the knee and ankle?

Answer 5

• Ball and socket joint forms the hip joint, formed by the head of the femur and the acetabulum
• Acetabulum forms a deep depression, hence higher stability than upper limb.
• However we require soft tissues, ligaments and muscles to support the deep ball and socket joint, without these we would have no ability to walk or shock absorb.
• Knee joint = modified hinge joint, allows some rotation to allow locking of the knee during standing = stability
• Ankle joint = synovial hinge joint formed between tibia, fibula and talus

Question 6

In which direction is the hip dislocated in each of the following pictures?

What signs would a patient show with each type of dislocation?

Answer 6

• Left hand image = posterior dislocation as the femur head has gone backwards
• Posterior dislocation displays with:
  
  • limb shortening on the side of the dislocation
  • hip flexion
  • internal rotation (hip flexors pull femur into flexed and internal rotated position).
• Right hand image = anterior dislocation as femur head has protruded forwards
• Anterior dislocation displays with:
  
  • Abudction
  • external rotation (lateral rotators pull femur into outwards position).

Question 7

What joints exist between the sacrum and the hip bones?

What happens on injury to sacroiliac joints?

What joint joins the two pelvic bones anteriorly?

What type of joint is this?

Answer 7

• Sacroiliac joints exist between hip bones and sacrum
• Sacroiliac joints are synovial joints = bones joined together by fibrous joint capsule continuous with periosteum of bones
• Fibrous joint with a lot of ligament reinforcement
• injury to sacroiliac joints –> equisite pain, radiates up back, into gluteal and perineal region due to innervation of sacroiliac joints via same nerve
• Anteriorly joined by pubic symphysis, fibrocartilaginous joint and a secondary cartilaginous joint
• Secondary cartilaginous joint = fibrocartilaginous and hyaline joints usually occurring in the midline (eg. intervertebral discs).

Question 8

What is the pelvic inlet?

What is the pelvic outlet?

Answer 8

• Pelvic inlet marks boundary between greater and lesser pelvis
• Markerd posteriorly by the sacral wings, laterally by the arcuate line of the ilium, anteiorly by pubic symphysis
• Pelvic inlet determines size and shape of the birth canal
• Pelvic outlet located at end of lesser pelvis bordered posteriroly by tip of coccyx, laterally by ischial tuberosities, anteriorly by the pubic arch

Question 9

What two main ligaments support the pelvic girdle?

What do these two ligaments form?

Answer 9

1. Sacrospinal ligament –> from the sacrum to the spine of the ischium (more superficial)
2. Sacrotuberous ligament –> from the sacrum to the ischial tuberosity

The sacrospinal and sacrotuberous ligaments form the greater and lesser sciatic foramen.

Question 10

What splits the greate sciatic foramen into two parts?

What does the greater sciatic foramen communicate with?

What does the lesser sciatic foramen communicate with?

Answer 10

• Piriformis muscle (powerful lateral rotator of hip) splits the greater sciatic foramen into an upper and lower portion
• Greater sciatic foramen connects the pelvic cavity to the gluteal region
• Lesser sciatic foramen connects the perineal region to the gluteal region

Question 11

What 3 bones form the hip bone?

Where do they unite? When does full fusion occur?

Answer 11

• Ilium, ischium and the pubic bones form the hip bones
• They unite at the acetabulum, prior to puberty they are separated by the triradiate cartilage
• Fusion begins age 15-17, only complete by young adulthood

Question 12

Label the image

How is the pelvic girdle angled?

Answer 12

• Pelvic girdle angled forwards such that the ASIS and pubic tubercles should be in alignment in a vertical plane.

Question 13

Label the image and highlight the importance/ functions of each component part of the femur

Answer 13

Left = anterior view of the L femur:

• Head –> articulates with the acetabulum forming ball and socket joint
• Neck –> clinically relevant, most likely region of fracture in osteoporitic/ penia patients when they fall, inherently weaker, region of most stress
• Greater trochanter –> attachment point for gluteus medius and gluteus minimus, stabilises the pelvis when walking
• Adductor tubercle –> attachment point of adductor muscles, palpable

Right = posterior view of L femur

• Lesser trochanter –> Attachment point for iliopsoas muscle, highly important hip flexor, allows us to walk and get up from sitting. Formed by iliacus and psoas muscles, extends from lumbar vertebrae, ilium and inserts onto femur.
• Linea aspera --> rige of bone formed by attachment of many powerful thigh muscles, and 3 intermuscular septa.
• Supracondylar region and condyles –> J shaped regions for the knee, articulates with tibia

Question 14

What is wolff’s law?

Answer 14

Wolff’s law = Bone is deposited and reabsorbed in accordance with the stressed placed upon it (remodels with mechanical stress).

Less stress = less bone

Remember bone = living tissue relatively flexible under stress

Question 15

What helps stabilise the hip joint?

Answer 15

• Hip joint is designed so that the acetabulum directly presses down onto the femoral head, which creates a more stable joint
• Hip joint also supported by muscles, ligaments, bone shape and the acetabular labrum

Question 16

What is the acetabular labrum?

What can produce pain in this region?

Answer 16

• Acetabular labrum is a horseshoe shaped ring of fibrocartilage that surrounds the acetabulum.
• It increases the depth of the joint and the surface and strength of the hip joint
• The acetabular labrum is closely apposed between the acetabulum and head of the femur and is both innervated and has its own blood supply
• Acetabular labrum can become impinged, trapped between the two surfaces of femoral head and acetabulum

Question 17

Describe the membranes that cover the hip joint

Answer 17

• Synovial membrane of the hip attaches to the margins of the articular surfaces of the femur and the acetabulum
• This synovial membrane is covered by a fibrous membrane
• Synovial membrane and fibrous membrane keep the ball and socket joint a unit

Question 18

What three ligaments further support the hip joint?

Answer 18

• Outside of the synovial and fibrous membrane 3 ligaments reinforce the external surface of the fibrous membrane and stabilise the joint
  
  • Iliofemoral –> from ilium the femoral head
  • Pubofemoral –> from pubic ramus to femoral head
  • Ischiofemoral –> from the ischium to the femoral head
• All of these ligaments are twisted, amd are tightest upon standing and moving
• Loosest when sitting, the ligaments become lax and untwisted –> highest risk of posterior hip dislocation

Question 19

Describe the blood supply to the femoral head:

What type of fracture increases the risk of avascular necrosis of the femoral head?

Answer 19

• The common iliac artery splits into an internal iliac (supplies pelvic region) and external iliac which becomes the femoral artery after it passes the inguinal ligament
• The femoral artery gives off deep femoral branch laterally
• This deep femoral branch gives off two circumflex arteries, the medial and lateral femoral circumflex arteries
• These circumflex arteries give off retinacular arteries which go on to supply the joint capsule and femoral head
• Intracapsular fractures are fractures occuring within the joint capsule, cuts off supply of the circumflex arteries and therefore increases your risk of avascular necrosis (medical emergency! Risk of loss femur head).
• Extracapsular fractures are fractures occuring outside the joint capsule, the circumflex arteries branch off the deep femoral artery proximal to the fracture and are still able to supply the femoral head.

Question 20

What ligament exists between the femoral head and the acetabulum?

Answer 20

• Ligamentum teres/ ligament of head of femur attaches femur head to acetabulum
• offers joint support and has a tiny artery within it that supplies small region of the articular surface
• It is not big enough to provide blood supply to the femoral head if the circumflex branches are lost. (intracapusular fracture).

Question 21

What is shenton’s line? Why is it clinically useful?

Is this X-ray from a female or male? How can you tell?

Answer 21

• Shenton’s line is a smooth curved, continous arched line that can be drawn from the femoral head to the obturator foramen
• Clinically useful as it can help detect subtle hip fractures without displacement
• X-ray is from a female, wider pelvic inlet, wider angle of the ilium, wider subpubic angle, soft tissue shadow shows mons pubis (lacking male genitalia).

Question 22

Is this X-ray from a male or female patient?

Is shenton’s line normal?

Answer 22

• X-ray is from a male patient, narrow pelvic inlet, higher arch and more angled ilium, acute subpubic angle, soft tissue shadow of male external genitalia
• Shentons line is normal

Question 23

Which fracture is extracapsular and which is intracapsular?

Which is at greatest risk of avascular necrosis of femoral head?

Answer 23

• Left hand image shows extracapsular fracture, running between greater and lesser trochanter (intratrochanteric fracture). Femoral circumflex arteries are more proximal to the fracture therefore still able to supply femoral head
• Right hand image shows intracapsular fracture of the R femoral neck, will cut off circumflex arteries, greater risk of avascular necrosis. –> medical emergency, attend quickly to prevent loss of femoral head

Question 24

What are the two main terms used to describe deformity in joints?

Which direction are these deformities?

If this were to occur in the hip, what would the angle be and where would the knee point?

Answer 24

• Valgus = distal part of the limb is directed AWAY from the midline
• Varus = distal part of the limb is directed TOWARDS the midline
• In the hip a valgus deformity would mean the angle of the femoral neck is larger than 130 degrees, the knees are moved away from the midline
• A varus deformity of the hip would mean the angle of the femoral neck is less than 130 degrees and the knees would be turned inwards (knock knees).

Question 25

Describe the deformities shown

Answer 25

* Left picture = Left valgus deformity of the knee * Middle picture also a valgus deformity of the knee * Right picture varus deformity of the knee (foot turned inwards).

Question 26

Describe the deformities shown

Answer 26

* L picture --\> hallux turned away from midline --\> valgus * R picture --\> hallux turned towards midline --\> varus

Question 27

How many compartments are there in the thigh? What are they wrapped in? What is the relevance of this?

Answer 27

* There are 3 compartments of the thigh: anterior, medial and posterior * Each is wrapped in its own thick deep fascia which forms the compartments * Each compartment contains muscles that have the same function, innervated by one nerve supply and have a major blood supply. * Problem of compartments --\> sealed units that can compress vessels and nerves in the event of increased pressure in the compartment (inflammation or rupture), leads to tissue death.

Question 28

What is the fascia lata? What is the iliotibial tract? What is its function? What can occur if it becomes inflamed?

Answer 28

* Lower limb fascia collectively surrounds the 3 compartments of the thigh and is called the fascia lata. * It condenses on the lateral aspect into the iliotibial tract * iliotibial tract acts as a muscle attachment point, assists in knee extension and stability * Gluteus maximus also inserts onto iliotibial tract * Saphenous vein runs superficial to the fascia * Inflammation of iliotibila tract can cause lateral knee pain

Question 29

Label the image

Answer 29

Question 30

What is the main function of the gluteal muscles? What are the main gluteal muscles? What are their innervations?

Answer 30

* Main function of gluteal muscles = hip/ trunk extension and pelvic stabilisation when walking --\> critical when climbing stairs or rising from a chair * Gluteus maximus largest of gluteal muscles, innervated by the inferior gluteal nerve (L5 -S2) * Proximal attachment to ilium, sacrum and sacral ligaments, attache distally to the femur and IT tract. * Gluteus medius and gluteus minimus vital for stabilising hip when walking, both innervated by superior gluteal nerve (L4- S1) * Gluteus medius and minimus both insert onto the greater trochanter of the femur *

Question 31

Label the image

Answer 31

Question 32

What is trendelenburg sign? What is trendelenburg gait?

Answer 32

Positive trendelenburg sign is when patient stands on one leg and the pelvis drops to the side opposite Trendelenburg gait is when the pelvis tilts towards the unsupported side during walking, also known as a lurch. Gluteus medius and minimus contract on the LEFT side when the RIGHT leg is in the air, prevents the pelvis from tilting towards the unsupported side (R side). If either the superior gluteal nerve (L4- S1) is damaged or the gluteus medius/ minimus is damaged may get trendelenburg sign and lurch.

Question 33

What is the main function of gluteus maximus?

Answer 33

* Gluteus maximus keeps the trunk from tipping forward when walking, damage to it makes getting out of chairs difficult * Patients compensate by lurching back on the affected side when the weaker limb is on the floor * Innervation to gluteus maximus = inferior gluteal nerve (L5 - S2)

Question 34

What is the sacral plexus? What are its branches?

Answer 34

* Sacral plexus is a network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb * located on the posterior/ lateral pelvic wall, anterior to the piriformis muscle * Formed by anterior rami of sacral spinal nerves S1- S4, also receives contributions from lumbar spinal nerves L4 and L5. Lumbosacral trunk contributes L4/ L5. * Mnemonic for branches: Some Irish Sailors Pester Polly: * Superior gluteal (L4/ 5- S1) * Inferior gluteal (L5- S2) * Sciatic (L4 -S3) * Posterior femoral cutaneous (S1- S3) * Pudendal (S2- S4) (S2/3/4 keeps poo off the floor --\> levator ani).

Question 35

What are the lateral rotator muscles? What is their function? What is their innervation? Why are these muscles important in hip replacement surgery?

Answer 35

* Lateral rotator muscles are deep in the gluteal region and insert onto the posterolateral side of the femur. * When they contract they help laterally rotate the hip and provide support * They pass between the pelvic bones, ligaments and insert onto proximal femur * All innervated by L4 -S2 * Top to bottom: * Piriformis --\> dividing greater sciatic foramen into supra nad infra piriform parts * Superior and inferior gemelli --\> from ischium to greater trochanter * Quadratus femoris --\> from lateral ischial tuberosity to intertrochanteric crest * Obturator internus --\> from obturator foramen to greater trochanter * Lateral rotators important in posterior approaches to hip replacement, often separated to access head and neck of femur

Question 36

What is the piriformis an important landmark?

Answer 36

* Piriformis muscle is an important landmark as it divides the greater sciatic foramen into supra and infra sciatic regions * Arising above the piriformis is the superior gluteal nerve and artery * Arising below piriformis are the inferior gluteal artery and nerve, and the sciatic nerve

Question 37

What are the nerve roots of the sciatic nerve? What is the route of travel of the sciatic nerve? What is the clinical relevance of this?

Answer 37

* Sciatic nerve nerve roots are L4 - S3 * Route of travel is it emerges inferior to piriformis, travels posteriorly in gluteal region, passes distally in posterior thigh compartment to emerge from under the hamstrings * Supplies posterior compartment of the thigh and the leg and foot. * Vulnerable to damage by: * Compression * IM injection * posterior dislocation * hip replacement

Question 38

Where are the safe zones for gluteal IM injections?

Answer 38

Safe zone sits superolaterally --\> avoid sciatic nerve. Method 1: * Vertical line through highest point of iliac crest * Horizontal line midway through ischial tuberosity and highest point of iliac crest Method 2: * Vertical line through highest point of crest * Line from PSIS to greater trochanter

Question 39

What is the muscle able to flex the hip powefully? What is it made up of? Where does it begin from and insert into? What is its innervation? What is the clinical relevance of this muscle?

Answer 39

* Iliopsoas muscle formed of the iliacus and psoas muscle * Psoas muscle from lumbar vertebrae, iliacus from the iliac fossa * Both insert onto the lesser trochanter and are able to flex hip powerfully * Innervated by branches of L1- L3 * Clinical relevance: The iliopsoas muscle is covered by a fibrous sheath that begins in the abdomen, infection can track down this sheath which presents as femoral swelling which can be mistaken for a femoral hernia (listen for bowel sounds, look for signs of inflammation/ redness). * Clinical relevance: Avulsion fracture --\> the iliopsoas muscle can contract so firmly it fractures off the lesser trochanter.

Question 40

What is the medial compartment of the thigh formed from? What muscles are contained in this region? What is their general action and general innervation?

Answer 40

* The medial compartment of the thigh is formed from adductor muscles * All innervated by the Obturator nerve (L2-L4) except pectineus which is innervated by the femoral nerve. * Superficially, pectineus and adductor longus which originate at the medial pelvis and insert medially onto the femur therefore adduct thigh at the hip. * Pectineus innervated by femoral nerve, originates at pelvis inserts onto pectineal line of femur * Adductor longus originates from pubis, fans out and inserts onto linea aspera of femur. * Deeper, adductor magnus (huge fan like muscle) and overlying it the smaller adductor brevis. * Adductor brevis directly underlies adductor longus, originates from body of pubis, inserts onto linea aspera of femur. * Adductor magnus has both adductor portion and hamstring portion. Originates from inferior ramus of pubic bone and ischial tuberosity, inserts onto linea alba and adductor tubercle of femur. * There is a hiatus called the adductor hiatus, in the adductor magnus through which the femoral artery passes to go behind the knee and continue as the popliteal artery. * Protects femoral artery from damage during knee flexion and extension

Question 41

Describe the anterior compartment of the thigh What muscles are included, what is their action, what is the general innervation?

Answer 41

* Muscles of anterior compartment are innervated by the femoral nerve (L2-L4) and act to flex thigh at the hip and extend the leg at the knee joint. 4 main muscles that form the quadriceps femoris. These muscles unite to form quadriceps tendon and attach to patella. Patella is attached to the tibia by patella ligament. Quadriceps femoris: 1. Rectus femoris --\> originates from ilium, attaches to the patella via quadriceps femoris tendon. Is the only muscle to cross both hip and knee joint so flexes thigh at hip joint and extends knee joint. Femoral nerve. 2. Vastus lateralis --\> from greater trochanter inserts onto patella via quadriceps tendon. Extend knee, stabilise patella, femoral nerve. 3. Vastus intermedius --\> anterior/ lateral femoral shaft into quadriceps tendon. Extend knee, stabilise patella, femoral nerve 4. Vastus medialis --\> From intertrochanteric line and medial linea aspera, into quadriceps tendon. Extend knee, stabilise patella, femoral nerve.

Question 42

Anterior compartment: What muscles (not in quadriceps femoris) are in this compartment? What is their action and innervation?

Answer 42

Sartorius --\> from ASIS to superior, medial tibia: * Flexes hip joint, abducts and laterally rotates. * Flexes knee joint * Femoral nerve Tensor fascia lata: * Inside iliotibial tract * Innervated by superior gluteal nerve (L4 -S1).

Question 43

What would be the result of loss of femoral nerve function or quadriceps femoris function? What would you notice in the event of a quadriceps muscle or tendon rupture?

Answer 43

* Weak or absent knee extension and difficulty getting out of a chair * muscle/ tendon rupture --\> pain and palpable sulcus

Question 44

What is the function of the patella? What type of bone is it? What ligaments help stabilise it? What has happened in this patient?

Answer 44

* The function of the patella is to ease the wear/tear/friction of flexing and extending the knee * Patella = sesamoid bone * Superiorly the quadriceps tendon inserts onto the patella * Inferiorly the patella gives off its own ligament called the patella ligament which inserts onto the anterior tuberosity of the tibia. * Fracture of the patella bone has occured in this patient

Question 45

What has happened in this patient?

Answer 45

The patella ligament has ruptured, causing avulsion fracture of the anterior tibial tuberosity and compromised knee extension.

Question 46

Describe the posterior compartment of the leg: What muscles are in this compartment? What is their point of origin? Why is this clinically relevant? What is their innervation and action?

Answer 46

* Posterior compartment of the leg is the hamstring region * General action is extension of the thigh at the hip and knee flexion * Innervation via tibial part of sciatic nerve (L5, S1-S2). * Sciatic nerve emerges from inferior region of piriformis, tibial part of sciatic nerve comes down into the posterior compartment and innervates it. * Common origin point for hamstring muscles = ischial tuberosity * Clinical relevance = ischial bursitis --\> inflammation of ischial bursa, causes pain when extending hip or flexing knee * 3 muscles: * Biceps femoris --\> has long head and short head (innervation to short head differs = L5, S1, common fibular nerve). * Semimembranosus --\> medial, deeper more muscle * Semitendinosus --\> laterally, at the top, long tendon * Clinical relevance: Rupture of hamstrings --\> pain, bruising/ ecchymosis.