Lower limb anatomy

Question 1

Motor: Knee extension, thigh flexion

Sensory: Anterior and medial aspect of the thigh and lower leg

Mechanism of Injury:
- Hip and pelvic fractures
- Stab/gunshot wounds

Answer 1

Femoral nerve

Question 2

Motor: Thigh adduction
Sensory: Medial thigh

Mechanism of Injury: Anterior hip dislocation

Answer 2

Obturator nerve

Question 3

Motor: None
Sensory: Lateral and posterior surfaces of the thigh

Mechanism of Injury: Compression of the nerve near the ASIS → meralgia paraesthetica

Answer 3

Lateral cutaneous nerve of the thigh

Question 4

Motor: Foot plantarflexion and inversion
Sensory: Sole of foot

Mechanism of Injury:
Not commonly injured as deep and well protected.
Popliteral lacerations, posterior knee dislocation

Answer 4

Tibial Nerve

Question 5

Motor: Foot dorsiflexion + eversion, Extensor hallucis longus
Sensory: Dorsum of the foot and the lower lateral part of the leg

Mechanism of Injury:
Injury often occurs at the neck of the fibula
Tightly applied lower limb plaster cast

**Injury causes foot drop

Answer 5

Common Peroneal Nerve

Question 6

Motor: Hip abduction
Sensory: None

Mechanism of Injury:
Misplaced intramuscular injection
Hip surgery
Pelvic fracture
Posterior hip dislocation

*Injury results in a positive Trendelenburg sign

Answer 6

Superior Gluteal Nerve

Question 7

Motor: Hip extension and lateral rotation
Sensory: None

Mechanism of Injury:
Generally injured in association with the sciatic nerve
Injury results in difficulty rising from seated position.
Can’t jump, can’t climb stairs

Answer 7

Inferior gluteal nerve