Lower Limb

Question 1

What are the parts of Lumbosacral plexus?

Answer 1

• femoral nerve
• obturator nerve
• superior gluteal nerve
• inferior gluteal nerve
• common fibular nerve (makes sciatic nerve)
• tibial nerve (makes sciatic nerve)

Question 2

Name the main terminal nerves of Lumbosacral plexus, innervated muscles groups, their function

Answer 2

• femoral nerve - anterior compartment of thigh - hip flexion, knee extension
• obturator nerve - medial compartment of thigh - adduction of thigh, medial rotation of thigh
• tibial nerve - posterior compartment of thigh, leg and foot (plantar muscles) - thigh extension, knee flexion, plantar foot flexion, digits flexion, inversion
• superficial fibular nerve - lateral compartment of leg - eversion
• deep fibular nerve - anterior compartment of leg - foot dorsiflexion, digits extension, inversion

Question 3

Name the main collateral nerves of Lumbosacral plexus, innervated muscles groups, their function

Answer 3

• superior gluteal nerve - gluteus medius, gluteus minimus, tensor fascia lata - stabilizing pelvis, hip abduction
• inferior gluteal nerve - gluteus maximus - hip extension, lateral rotation of thigh

Question 4

How does segmental innervation to muscles of lower limb occur?

Answer 4

• Muscles that cross the anterior side of the hip are innervated by L2 and L3
• Muscles that cross the anterior side of the knee are innervated by L3 and L4
• Muscles that cross the anterior side of the ankle are innervated by L4 and L5 (dorsiflexion)
• Muscles that cross the posterior side of the hip are innervated by L4 and L5
• Muscles that cross the posterior side of the knee are innervated by L5 and S1
• Muscles that cross the posterior side of the ankle are innervated by S1 and S2 (plantar flexion)

Question 5

What are the consequences of posterior hip dislocation?

Answer 5

Sciatic nerve lesion ->

• posterior sensory loss
• loss of all functions below the knee

Question 6

What is the most frequently damaged nerve? Where does it lay? What are the consequences of its lesion?

Answer 6

Common fibulary nerve. It crosses fibula near the neck.
Consequences of its lesion:
- foot drop
- loss of eversion
- sensory loss on the lateral surface of the hip

Question 7

What is the piriformis syndrome?

Answer 7

When common fibulary nerve passes through piriformis muscle instead of passing inferiorly. Leads to motor and sensory loss of anterior and lateral leg

Question 8

What are the consequences of tibial shaft fractures?

Answer 8

It may damage anterior or posterior tibial artery, what leads to anterior or posterior compartment syndrome

Question 9

What are the components of femoral triangle?

Answer 9

• inguinal ligament
• sartorius muscle
• adductor longus muscle

Question 10

What are the consequences of the fracture of the femoral neck?

Answer 10

Avascular necrosis of the head of the femur

Question 11

Why is medial (tibial) meniscus damaged more frequently than lateral (fibular)?

Answer 11

Because it’s connected to medial collateral ligament (fibular meniscus is free, so movable)

Question 12

What are the drawer signs?

Answer 12

Tearing of the anterior cruciate ligaments allows the tibia to be easily pulled forward (anterior drawer sign). Tearing of the posterior cruciate ligament allows the tibial to be easily pulled posteriorly (posterior drawer sign)

Question 13

What is the most commonly damaged ankle ligament?

Answer 13

Anterior talofibular

Question 14

What is Trendelenburg sign?

Answer 14

Standing on 1 foot -> pelvis on the other side is lower (failure of gluteus medius and minimus on the affected (supporting) side to adduct the opposite side)

Question 15

What is Iliotibial band syndrome?

Answer 15

Overuse injury of lateral knee that occurs primarily in runners. Pain develops 2° to friction of iliotibial band (crosses knee laterally) against lateral femoral epicondyle.

Question 16

What is Medial tibial stress syndrome?

Answer 16

Also called shin splints. Common cause of shin pain and diffuse tenderness in runners and military recruits. Caused by bone resorption that outpaces bone formation in tibial cortex.

Question 17

What is Limb compartment syndrome?

Answer 17

Increased pressure within a fascial compartment of a limb (defined by compartment pressure to diastolic
blood pressure gradient of < 30 mm Hg) -> Ž venous outflow obstruction and arteriolar collapse -> anoxia and necrosis. Causes include significant long bone fractures, reperfusion injury, animal venoms. Presents with severe pain and tense, swollen compartments with limb flexion. Motor deficits are late sign of irreversible muscle and nerve damage.

Question 18

What is Plantar fasciitis?

Answer 18

Inflammation of plantar aponeurosis characterized by heel pain (worse with first steps in the
morning or after period of inactivity) and tenderness.

Question 19

What is Developmental dysplasia of the hip?

Answer 19

Abnormal acetabulum development in newborns. Results in hip instability/dislocation. Commonly
tested with Ortolani and Barlow maneuvers (manipulation of newborn hip reveals a “clunk”).
Confirmed via ultrasound (x-ray not used until ~4–6 months because cartilage is not ossified).
Treatment: splint/harness.

Question 20

What is Legg-Calvé-Perthes disease?

Answer 20

Idiopathic avascular necrosis of femoral head. Commonly presents between 5–7 years with
insidious onset of hip pain that may cause child to limp. More common in males (4:1 ratio). Initial
x-ray often normal.

Question 21

What is Slipped capital femoral epiphysis?

Answer 21

Classically presents in an obese ~12-year-old child with hip/knee pain and altered gait. Increased axial force on femoral head Ž epiphysis displaces relative to femoral neck (like a scoop of ice cream slipping off a cone). Diagnosed via x-ray. Treatment: surgery.

Question 22

What is Osgood-Schlatter disease (traction apophysitis)?

Answer 22

Overuse injury caused by repetitive strain and chronic avulsion of the secondary ossification center of proximal tibial tubercle. Occurs in adolescents after growth spurt. Common in running and jumping athletes. Presents with progressive anterior knee pain.

Question 23

Name parts of the knee exam

Answer 23

Anterior drawer sign
Bending knee at 90° angle,  anterior gliding
of tibia (relative to femur) due to ACL injury.
Lachman test also tests ACL, but is more
sensitive ( anterior gliding of tibia [relative to
femur] with knee bent at 30° angle).

Posterior drawer sign
Bending knee at 90° angle,  posterior gliding of
tibia due to PCL injury.

Abnormal passive abduction
Knee either extended or at ∼ 30° angle, lateral
(valgus) force -> Ž medial space widening of
tibia -> Ž MCL injury.

Abnormal passive adduction
Knee either extended or at ~ 30° angle, medial
(varus) force -> Ž lateral space widening of tibiaŽ LCL injury.

McMurray test 
During flexion and extension of knee with
rotation of tibia/foot:
ƒPain, “popping” on external rotation
medial meniscal tear (external rotation
stresses medial meniscus)
ƒPain, “popping” on internal rotation
Žlateral meniscal tear (internal rotation
stresses lateral meniscus)