Week 7 - Osteology of the lower limb, anterior thigh Flashcards
Which muscles are found in the medial compartment of the thigh?
- Obturator externus
- Adductor brevis
- Adductor longus
- Adductor magnus
- Gracilis
Which muscles are found in the anterior compartment of the thigh?
- Psoas major
- Iliacus
- Pectineus
- Sartorius
- Recturs femoris
- Vastus lateralis
- Vastus medialis
What is the iliopsoas?
The posts major and the iliacus come together to form a tendon
- Hence why they are commonly referred to as 1 muscle
What are the actions of the iliopsoas?
- Flexes the lower limb at the hip joint
- Assists in lateral rotation at the hip joint
What are the attachments of the adductor brevis?
- Originates from the body of the pubis and inferior pubic rami
- Attaches to the linea aspera on the posterior aspect of the femur
What innervates the adductor brevis?
Obturator nerve
What are the actions of the adductor brevis?
Adduction of the thigh
What are the attachments of the obturator externus?
- Originates from the membrane of the obturator foramen and adjacent bone
- Attaches to the posterior aspect of the greater trochanter
What innervates the obturator externus?
Obturator nerve
What are the actions of the obturator externus?
Laterally rotates the thigh
What are the attachments of the adductor magnus?
Adductor part:
- Originates from the inferior rami of the pubis and the rami of the ischium
- Attaches to the linea aspera of the femur
Hamstring part
- Originates from the tibial tuberosity
- Attaches to the adductor tubercle on the distal and medial side of the femur
What are the actions of the adductor magnus?
Both parts adduct the thigh
- Adductor part also flexes the thigh
- Hamstring part also extends the thigh
What innervates the adductor magnus?
- Adductor part: obturator nerve
- Hamstring part: tibial nerve
What are the attachments of the adductor longus?
- Originates from the pubis
- Expands into a fan shape
- Attaches broadly to the linea aspera of the femur
What are the actions of the adductor longus?
- Adduction of the thigh
- Medial rotation of the thigh
What innervates the adductor longus?
Obturator nerve
What are the attachments of the gracilis muscle?
- Originates from the inferior rami of the pubis and the body of the pubis
- Descends almost vertically down the leg
- Attaches to the medial surface of the tibia, in-between the tendons of the sartorius (anteriorly) and the semitendinous (posteriorly)
What are the actions of the gracilis muscle?
- Adduction of the thigh at the hip
- Flexion of the leg at the knee
What innervates the gracilis muscle?
Obturator nerve
What are the attachments of the psoas major?
- Originates from the lumbar vertebrae
- Inserts into the lesser trochanter of the femur, along with the iliacus
What innervates the psoas major?
Anterior rami of L1-L3
What are the attachments of the iliacus?
- Originates from the iliac fossa of the pelvis
- Inserts onto the lesser trochanter of the femur, along with psoas major
What innervates the iliacus?
Femoral nerve
What are the attachments of the pectineus?
- Originates from the pectineal line on the anterior surface of the pelvis
- Attaches to the pectineal line on the posterior side of the femur, just inferior to the lesser trochanter
What are the actions of pectineus?
- Adduction at the hip joint
- Flexion at the hip joint
What innervates pectineus?
Femoral nerve
What are the attachments of sartorius?
- Originates from the anterior superior iliac spine
- Attaches to the superior, medial surface of the tibia
What are the actions of sartorius?
- At the hip joint = flexor, abductor and lateral rotator
- At the knee joint = flexor
The “tailor’s muscle” so allows you to sit cross-legged
What innervates sartorius?
Femoral nerve
What is quadriceps femoris?
One of the most powerful muscles of the body
- Forms the main bulk of the thigh
- Consists of 4 individual muscles (3 vastus and rectus femoris)
- Main extensor of the knee
Where does quadriceps femoris attach?
To the patella via a tendon
- The patella then attaches to the tibia by the patella tendon
What are the 3 vastus muscles in quadriceps femoris?
- Vastus medialis
- Vastus intermedius
- Vastus lateralis
What is the action of the vastus muscles?
Collectively, they extend at the knee joint
What innervates the vastus muscles?
Femoral nerve
What are the attachments of rectus femoris?
- Originates from the ilium, just superior to the acetabulum
- Runs straight down the leg
- Attaches to the patella by the quadriceps femoris tendon
What are the actions of rectus femoris?
- Flexes the leg at the hip joint
- Extends at the knee joint
What bones are found in the lower limb?
- Pelvic girdle (hip bones, sacrum, coccyx)
- Femur
- Tibia
- Fibula
- Foot bones
What are the articulations of the hip bone?
- Sacroiliac joint: articulation with sacrum
- Pubic symphysis: articulation with the corresponding hip bone
- Hip joint: articulation with the head of femur
What are the 3 parts that make up the hip bone?
- Ilium
- Ischium
- Pubis
What was the structure of the hip bone prior to puberty?
Triradiate cartilage separated the ilium, ischium and pubis
- They begin to fuse at the age of 15-17
What is the acetabulum?
A cup-shaped socket
- Formed by the fusion of the ilium, ischium and pubis
- The head of the femur articulates with it to form the hip joint
What is the structure of the ilium?
- The superior part of the hip bone
- The widest and largest of the 3 parts
- Immediately above the acetabulum, it expands to form the wing
Describe the wing of ilium
It has 2 surfaces:
- Inner: concave, known as the iliac fossa
- External: convex, provides attachments to the gluteal muscles, also known as the gluteal surface
The superior margin of the wing is thickened, forming the iliac crest
- The iliac crest extends from the anterior superior iliac spine to the posterior superior iliac spine
Which muscles attach to the ilium?
- Gluteal muscles attach to the external surface of the ilium at the anterior, posterior and inferior gluteal lines
- The iliacus muscle attaches medially at the iliac fossa
What is the structure of the pubis?
The most anterior portion of the hip bone
Consists of a body and superior + inferior rami
- The body is located medially
- The superior rami extends laterally from the body, forming part of the acetabulum
- The inferior rami projects towards, and joins, the ischium
What does the pubis articulate with?
Its opposite pubis body
- At the pubic symphysis
What encloses the obturator foramen?
- Inferior and superior pubic rami
- Ischiopubic ramus
What passes through the obturator foramen?
- Obturator nerve
- Obturator artery
- Obturator vein
What is the structure of the ischium?
- The posterioinferior part of the hip bone
- Composed of a body and an inferior + superior ramus
- The inferior ischial ramus combines with the inferior pubic ramus to form the ischiopubic ramus
- The posteroinferior aspect of the ischium forms the ischial tuberosities
- On the posterior aspect of the ischium there is an indentation known as the greater sciatic notch
Which ligaments attach to the ischium?
Sacrospinous:
- Runs from the ischial spine to the sacrum
- This creates the greater sciatic foramen
The sacrospinous ligament and the sacrotuberous ligament run from the sacrum to the ischial tuberosity
- Forms the lesser sciatic foramen
What transcends through the greater sciatic foramen?
- Lower limb neurovasculature
- Piriformis muscle
What are the common ways of fracturing the hip bones?
- Direct trauma (e.g. vehicular accident)
- Forces transmitted from the lower limb (e.g. a heavy fall on the feet)
Where do fractures often occur on the hip bones?
- Pubic rami
- Acetabulum
- In the region of the sacroiliac joint
What is a common complication of a hip bone fracture?
Soft tissue injury
- The bladder and urethra are at high risk of damage
What is the pelvic girdle?
- A ring-like structure
- Located in the lower part of the trunk
- Connects the axial skeleton to the lower limbs
- Consists of: 2 hip bones, sacrum, coccyx
What are the articulations within the pelvis?
- Sacroiliac joints (2): between the ilium of the hip bones and the sacrum
- Sacrococcygeal symphysis: between the sacrum and coccyx
- Pubic symphysis: between the pubis bodies of the 2 hip bones
What are the functions of the pelvic girdle?
- Transfer of weight from the upper axial skeleton to the lower appendicular components of the skeleton, especially during movement
- Provides attachment for a number of muscles and ligament used in locomotion
- Contains and protects the abdominopelvic and pelvic viscera
What is the main function of the femur?
To transmit forces from the tibia to the hip joint
- Also acts as the place of origin and attachment f many muscles and ligaments
Describe the proximal part of the femur
Forms the hip joint with the pelvis
Consists of:
- Head (has a smooth surface with a depression on the medial surface for the attachment of the ligament of the head)
- Neck (connects the head of the femur with the shaft, cylindrical, projects in a superior and medial direction)
- 2 bony processes (trochanters)
- Intertrochanteric line
- Intertrochanteric crest
What is the intertrochanteric line?
- A ridge of bone that runs in an inferomedial direction on the anterior surface of the femur
- Connects the 2 trochanters together
- The iliofemoral ligament attaches here
- After it passes the lesser trochanter on the posterior surface, it is known as the pectineal line
What is the intertrochanteric crest?
- A ridge of bone that connects the 2 trochanters together
- It sticks out more than the intertrochanteric line
- Located on the posterior surface of the femur
- There is a rounded tubercle on its superior half called the quadrate tubercle
- – The quadrates femoris attaches here
Describe the femur trochanters?
Greater:
- A projection of bone that originates from the anterior shaft, just lateral to where the neck joints
- Angled superiorly and posteriorly
- Can be found on both the anterior and posterior sides of the femur
- The site of attachment of the abductor and lateral rotator muscles of the leg
Lesser
- Much smaller than the greater trochanter
- Projects from the posteromedial side of the side, just inferior to the neck-shaft junction
- The psoas major and iliacus muscles attach here
Describe the shaft of the femur
- Descends in a slight medial direction
- – This brings the knees closer to the body’s centre of gravity, increasing stability
- On its posterior surfaces there are roughened ridges of bone called the linea aspera
Describe the linea aspera
Roughened ridges of bone on the posterior surface of the femur
- Proximally, the medial border becomes the pectineal line
- The lateral border becomes the gluteal tuberosity
- – Gluteus maximus attaches to it
- Distally, it widens and forms the floor of the popliteal fossa
- – The medial and lateral borders form the medial and lateral supracondylar lines
Describe the distal part of the femur
Consists of:
Medial and lateral condyles
- Rounded areas at the end of the femur
- The posterior and inferior surfaces articulate with the tibia and menisci of the knee
- The anterior surface articulates with the patella
Medial and lateral epicondyles
- Bony elevations on the non-articular areas of the condyles
- The area of attachment of some muscles and the collateral ligaments of the knee joints
Intercondylar fossa
- A depression found on the posterior surface of the femur
- It lies in between the 2 condyles
- It contains 2 facets for attachment of internal knee ligaments
Facet for attachment of the posterior cruciate ligament
- Found on the medial wall of the intercondylar fossa
- A large rounded flat face
- The posterior cruciate ligament of the knee attaches to it
Facet for attachment of the anterior cruciate ligament
- Found on the lateral wall of the intercondylar fossa
- Smaller than the facet on the medial wall
What are the 2 types of femoral neck fractures?
Intracapsular and extracapsular
Describe an intracapsular femoral neck fracture
- More common in the elderly, especially women
- A result of a minor trip or stumble
- Occurs within the capsule of the hip joint
- It can damage the medial femoral circumflex artery (may lead to avascular necrosis of the femoral head)
- The distal fragment is pulled upwards and rotated laterally
- Clinically, this manifests as a shorter leg length, with the toes pointing laterally
Describe an extracapsular femoral neck fracture
- More common in young and middle aged people
- In these fractures, the blood supply to the head of femur is intact
- The leg is shortened and laterally rotated
How do fractures of the femoral shaft occur?
- Relatively uncommon
- Require a lot of force
- Usually a consequence of a traumatic injury, such as a vehicular accident
How do femoral shaft fractures present?
A spiral fracture:
- Can present with leg shortening, due to the fragments overriding (pulled by the attached muscles)
- Since the method of injury is usually high energy, the surrounding soft tissues may also be damaged
- Femoral nerve palsy is a possible sequelae
- It is important to ensure the blood supply from the femoral artery hasn’t been compromised, as it supplies the remainder of the lower limb
Describe the tibia
- The main bone of the leg
- Forms what is commonly known as the shin
- Expands at the proximal and distal ends, articulating at the knee and ankle joints respectively
- Second largest bone in the body
- Functions as a weight bearing structures
- Split into 3 parts: proximal, shaft and distal
Describe the proximal part of the tibia
- Widened by the medial and lateral condyles
- – Aids in weight bearing
- – They form a flat surface, known as the tibial plateau, which articulates with the femoral condyles to form the major articulation of the knee joint
- Located between the condyles is a region called the intercondylar eminence
- – Consists of 2 tubercles and a roughened area
- – The main site of attachments for the ligaments and the menisci of the knee joint
- – The tibial intercondylar tubercles fit into the intercondylar fossa of the femur
- Tibial tuberosity
- – Located on the anterior surface of the proximal tibia, inferior to the condyles
- – Where the patella ligament attaches
Describe the shaft part of the tibia
Has 3 borders and 3 surfaces (anterior, posterior and lateral)
- Anterior border:
- – The start of the anterior border is marked by the tibial tuberosity
- – Palpable down the anterior surface of the leg as the shin
- – The periosteal covering of the tibia is susceptible to damage
- Posterior surface:
- – Marked by a ridge of bone called the soleal line
- – Runs inferomedially
- – Eventually blends with the medial border of the tibia
- – The soleus muscle originates from here
- Lateral border:
- – Also known as the interosseous border
- – Gives attachment to the interosseous membrane
Describe the distal part of the tibia
- Widens to help with weight bearing
- There is a bony projection continuing inferiorly on the medial side
- – Called the medial malleolus
- – Articulates with the tarsal bones to form part of the ankle joint
- On the posterior surface, there is a groove where the tibialis posterior muscle attaches
- Laterally, there is a notch where the fibula is bound to the tibia (called the fibula notch)
Describe tibial fractures
- Relatively common
- Occur most frequently in the middle-aged and elderly
- If the fibula is not fractured, it supports the tibia, so displacement of the fragments is minimal
- The proximal end is the most vulnerable to damage
- – Usually results from some traumatic accident
- – The condyles may be broken up in the fracture
- – It is not uncommon for there to be injury to the ligaments of the knee
- At the ankle, the medial malleolus can be fractured
- – Caused by the ankle being twisted inwards
- – The talus of the foot is forced against the medial malleolus, causing a spiral fracture
Describe the fibula
- A bone in the leg
- Found laterally to the tibia
- At the proximal end it has an enlarged head
- – This contains a facet for articulation with the lateral condyle of the tibia
- On the posterior and lateral surface of the fibular neck, the common fibular nerve can be found
- The fibular shaft has 3 surfaces: anterior, lateral and posterior
- – The leg is split into 3 compartments, so each surface faces its respective compartment
- – Distally, the lateral surface continues inferiorly and is called the lateral malleolus
What is the main function of the fibula?
Acts as an attachment for muscles
What is the most common place for a fibular fracture?
The lateral malleolus
How can a lateral malleolus fracture occur?
- By forced external rotation of the ankle
- – This force of the talus against the bone causes a spiral fracture
- By the foot being twisted outwards (eversion)
- – The talus presses against the lateral malleolus
What is the role of the bones of the foot?
- They provide mechanical support for the soft tissues
- Help he foot to withstand the weight of the body
How can the bones of the foot be divided into 3 categories?
- Tarsals
- Metatarsals
- Phalanges
What are the tarsals?
A set of 7 irregularly shaped bones
- Situated proximally in the foot, in the ankle area
- Organised into 3 rows: proximal, intermediate and distal
Which bones are found in the proximal group of tarsal bones?
Talus and calcaneus
- They form the bony framework around the proximal ankle and heel area
Describe the talus bone
- The most superior of the tarsal bones
- Has 3 articulations
- – Superiorly: ankle joint = between the talus and the bones of the leg
- – Inferiorly: subtalar joint = between the talus and calcaneus
- – Anteriorly: talnavicular joint = between the talus and navicular
- Main function = to transmit forces from the tibia to the heel bone
- Numerous ligaments attach to it
Describe the calcaneus bone
- Lies underneath the talus bone
- Has 2 articulations:
- – Superiorly: subtalar joint
- – Anteriorly: calcaneocuboid joint = between the calcaneus and the cuboid
- It is thick and sturdy
- Acts to transmit forces from the talus to the ground
- The posterior aspect of the calcaneus is marked by the calcaneal tuberosity
- – The achilles tendon attaches to it
Which bones are found in the intermediate group of tarsal bones?
Only 1 bone: the navicular
Describe the navicular bone
- Articulates with:
- – The talus posteriorly
- – The cuneiform bones anteriorly
- – Cuboid bone laterally
- On its plantar surface, there is a tuberosity for the attachment of the tibialis posterior tendon
Which bones are found in the distal group of tarsal bones?
- Cuboid
- 3 cuneiform bones
- They articulate with the metatarsals of the foot
Describe the cuboid bone
- Most lateral bone in the distal row
- Articulates with:
- – The calcaneus posteriorly
- – 2 metatarsals anteriorly
- Shaped like a cube
- Its inferior surface is marked by a groove for the fibularis longus muscle
Describe the cuneiform bones
- Lateral, intermediate and medial cuneiform bones
- Articulate with the navicular posteriorly
- The shape of the bones helps form a transverse arch across the foot
Describe the metatarsals
- Located in the midfoot, between the tarsals and phalanges
- Numbered I-V (medial to lateral)
- Each has a similar structure
- – Consist of a distal head and proximal base
- – These are joined by a shaft of bone
- Have 3 articulations
- – Proximally: tarsometatarsal joint = between the metatarsal bases and the cuneiforms or cuboid bones
- – Laterally: intermetatarsal joint = between the metatarsal and the adjacent metatarsals
- – Distally: metatarsophalangeal joint = between the metatarsal head and the proximal phalanx
- They connect the phalanges to the tarsals
Describe the phalanges
- The bones of the toes
- Each toe has 3 phalanges (a proximal, distal and intermediate)
- – Except the big toe, which only has 2
Which of the tarsal bones are most frequently fractured?
Talus and calcaneus
Describe talus fractures
Can occur in 2 places: neck or body
Neck:
- Caused by excessive dorsiflexion of the foot
- The neck of the talus is pushed against the tibia
- The blood supply to the talus may be disturbed, leading to avascular necrosis of the bone
Body:
- Usually occur from jumping from a height
The malleoli of the leg bones act to hold the fragments together, so there is little displacement of the fracture pieces
Describe calcaneus fractures
- Often fractured in a ‘crush’ type injury
- Most common mechanism = falling onto the heel from a height
- – The talus is driven into it
- – The bone can break into several pieces (a comminuted fracture)
- – Upon x-ray it will appear shorter and wider
- Even after treatment, a calcanea fracture can cause further problems
- – The sub-talar joint is usually disrupted, causing the joint to become arthritic
- – The patient will experience pain upon inversion and eversion
- – Can make walking on uneven ground particularly painful
How can fractures of the metatarsal bones occur?
- Direct blow to the foot = most common method, usually from a heavy object dropping onto the foot
- Stress fracture = an incomplete fracture caused by repeated stress to the bone; common in athletes
- Excessive inversion of the foot = if the foot is violently inverted, the fibulas brevis muscle can tear off the base of metatarsal V
What is the femoral triangle?
A hollow in the anterior thigh region
- Many neuromuscular structures pass through it
What are the borders of the femoral triangle?
- Superior = the inguinal ligament
- Lateral = the medial border of the sartorius muscle
- Medial = medial border of the adductor longus muscle
- Floor = rest of adductor longs, the pectineus and iliopsoas
- Roof = fascia lata
Where is the inguinal ligament found?
From the anterior superior iliac spine to the pubis tubercle
What is the role of the inguinal ligament in the femoral triangle?
Acts as a flexor retinaculum
- Supports the contents of the femoral triangle during flexion at the hip
What are the contents of the femoral triangle?
- Femoral nerve: inmervates the anterior compartment of the thigh and provides sensory branches for the leg and foot
- Femoral artery: responsible for the majority of the arterial supply to the lower limb
- Femoral vein: the great saphenous vein drains into it
- Femoral canal: a structure which contains deep lymph nodes and vessels
What is the femoral sheath?
A fascial compartment within the femoral triangle
- It contains the femoral artery, vein and canal
How can the femoral pulse be measured?
- Just inferior to where the femoral artery crosses the inguinal ligament, it can be palpated to measure the femoral pulse
- It crosses exactly midway between the pubic symphysis and ASIS
- Th presence of the pulse means that blood is reaching the lower extremity
Why is the femoral artery clinically relevant?
It is located superficially in the femoral triangle so is easy to access
- Can be used for coronary angiography and can be catheterised to draw blood for arterial blood gases
What is a hernia?
A condition in which part of an organ is displaced and protrudes through the wall of the cavity containing it
What is a femoral hernia?
Part of the bowel pushes into the femoral canal, underneath the inguinal ligament
- Manifests clinically as a lump/bulge in the area of the femoral triangle
- Usually requires surgical intervention to treat
What is the femoral canal?
An anatomical compartment located in the anterior thigh, within the femoral triangle
- The smallest and most medial part of the femoral sheath
What are the borders of the femoral canal?
- Medial: lacunar ligament
- Lateral: femoral vein
- Anterior: inguinal ligament
- Posterior: pectineal ligament, superior rami of the pubi and the pectineus muscle
Where is the opening to the femoral canal found?
At its superior border
- Enclosed by a connective tissue layer called the femoral septum
- This septum is pierced by the lymphatic vessels exiting the canal
What are the contents of the femoral canal?
- Lymphatic vessels (drain the deep inguinal lymph nodes
- Deep lymph node
- Empty space (allows distension of the adjacent femoral vein)
- Loose connective tissue
What is the adductor canal?
A muscular tunnel in the thigh
- Begins at the inferior end of the femoral triangle
- Terminates at the adductor hiatus
What are the boundaries of the adductor canal?
- Anterior = sartorius muscle
- Posteromedial = adductor longus and adductor magnus muscles
- Lateral = vastus medialis muscle
What are the contents of the adductor canal?
- Femoral artery
- Femoral vein
- Nerve to vastus medialis
- Saphenous nerve
- Branch of obturator nerve
What is the lumbosacral plexus?
The anterior divisions of the lumbar nerves, sacral nerves and coccygeal nerve
- Usually divided into 3 parts: lumbar plexus. sacral plexus, pudendal plexus
What is the lumbar plexus?
A network of nerve fibres that supplies the skin and musculature of the lower limb
- Located in the lumbar region, within the substance of the psoas major muscle
- Formed by the anterior rami of the lumbar spinal nerves L1, L2, L3 and L4
- Also receives contribution from T12
- They divide into several cords
- – These cords then combine together to form 6 major peripheral nerves of the lumbar plexus
- – These nerves then descend down the posterior abdominal wall to reach the lower limb
What is the sacral plexus?
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 performs muscle
- Formed by the anterior rami of the sacral spinal nerves S1, S2, S3 and S4
- – Also receives contributions from the lumbar spinal nerves, L4 and L5
- Divide into several cords
- – These then combine to form the 5 major peripheral nerves of the sacral plexus
- – Thes descend down the posterior pelvic wall
- The nerves have 2 main destinations:
- – Leave the pelvis via the greater sciatic foramen and innervate the gluteal region
- – Remain in the pelvis and innervate the pelvic muscles, organs and perineum
What are the 2 major superficial veins of the leg?
- Great saphenous vein
- Small saphenous vein
Describe the passage of the great saphenous vein
- Formed by the dorsal venous arch of the foot and the dorsal vein of the great toe
- It ascends the medial side of the leg
- Passes anteriorly to the medial malleolus
- Passes posteriorly to the medial condyle at the knee
- As it moves up the leg, it receives tributaries from other small superficial veins
- It terminates by draining into the femoral vein immediately inferior to the inguinal ligament
Describe the passage of the small saphenous vein
- Formed by the dorsal venous arch of the foot and the dorsal vein of the little toe
- It moves up the posterior side of the leg
- Passes posteriorly to the lateral malleolus, along the lateral border of the calcaneal tendon
- It moves between the 2 heads of the gastrocnemius muscle
- Empties into the popliteal vein in the popliteal fossa
What are the consequences of damage to the obturator nerve due to a superior pubic rami fracture?
- Numbness and paraesthesia on the medial aspect of the thigh
- Patient could present with posture and gait problems due to the loss of adduction
How do you test the patella tendon reflex?
- Tap the patellar ligament with a reflex hammer
- – Should make the leg extend
- – Should feel the quadriceps contract
- Tests the integrity of the femoral nerve and the L2-L4 segments of the spinal cord
Discuss pulled groin muscles
A strain, stretching and probably some tearing of the proximal attachments of the anteromedial thigh muscles have occurred
- Usually involves the flexor and adductor thigh muscles
- Usually occurs in sports the require quick starts or extreme stretching
