Peripheral Mononeuropathy - Common Peroneal Nerve

Question 1

Anatomy of Sciatic Nerve.

Answer 1

1. L4-S3.
2. Inferior to Piriformis, Deep to Biceps Femoris.
3. Bifurcation at Popliteal Fossa : Tibial Nerve and Common Fibular/Peroneal Nerve.

Question 2

Functions of Sciatic Nerve.

Answer 2

1. Motor : Posterior Compartment of Thigh + Hamstring Adductor Magnus.
2. No Sensor yFunction.

Question 3

What is Piriformis Syndrome?

Answer 3

Compression of Sciatic nerve by Piriformis Muscle - Deep Gluteal Syndrome.

Question 4

Function of Tibial Nerve.

Answer 4

1. Motor - Calf and Intrinsic Muscles of Foot.

2. Sensory - Posterolateral Leg, Lateral Foot and Sole of Foot.

Question 5

Functions of Common Peroneal Nerve.

Answer 5

1. Motor - Anterior Leg Muscles, Lateral Leg, Intrinsic Muscles of Foot.
2. Sensory - Lateral Leg and Dorsum of Foot.

Question 6

Where does Injury often occur for the Common Peroneal Nerve?

Answer 6

Neck of fibula.

Question 7

Clinical Features of Common Peroneal Nerve Palsy (5).

Answer 7

1. FOOT DROP.
2. Weakness of Dorsiflexion and Eversion.
3. Weakness of Extensor Hallucis Longs.
4. Sensory Loss of Common Peroneal Distribution.
5. Wasting - Anterior Tibial and Peroneal Muscles.

Question 8

Differential Diagnoses of Foot Drop (5).

Answer 8

1. Common Peroneal Nerve Lesion (commonest).
2. L5 Radiculopathy (with weak hip abduction).
3. Sciatic Nerve Lesion.
4. Superficial/Deep Peroneal Nerve Lesion.
5. Central Nerve Lesions e.g. Stroke.

Question 9

Management of Common Peroneal Nerve Palsy.

Answer 9

1. Conservative e.g. Avoid Leg Crossing, Squatting, Kneeling.

Question 10

Prognosis of Common Peroneal Nerve Palsy.

Answer 10

Improvement in function after 2-3 months.