Feature seen in common peroneal nerve injury

COMMON PERONEAL NERVE:- Smaller terminal branch of sciatic nerve.Root value: dorsal division of ventral rami of L4,L5,S1,S2.Beginning: begins in back of thigh as a smaller subdivision of the sciatic nerve. Course:lies in upper lateral pa of popliteal fossa. It turns around the lateral surface of the fibula. Then it lies in the substance of peroneus longus muscle.Terminates by dividing into two terminal branches- superficial and deep peroneal. Commonest nerve to be paralysed.Causes of injury:1. Fracture neck of fibula.2. Lathi injury on lateral side of knee joint.3. Due to plaster on leg.- nerve get compressed between hard plaster and neck of fibula. To prevent this cotton must be placed on the upper lateral side of the leg. Effects of injury:-1. Motor loss: dorsiflexors and eveors of foot affected. Results in foot drop. Foot is plantar flexed due to paralysis of muscle of anterior compament.2. Sensory loss: back of leg, lateral side of leg and dorsum of foot.3. Aicular loss: lateral side of knee joint. {Reference: BDC 6E pg no.176}