A patient presents with inability to dorsiflex the foot and extend the toes, with foot drop and numbness over the first web space dorsally. Tibialis anterior is paralyzed but tibialis posterior is intact. Which nerve is most likely injured?

• A Deep peroneal nerve in the anterior compartment ✓
• B Common peroneal nerve at the fibular neck
• C Sciatic nerve at the gluteal region
• D L4 nerve root

Explanation

Deep peroneal nerve injury selectively affects the anterior compartment muscles (tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius) causing foot drop and loss of toe extension. Sensory loss is confined to the first web space. Tibialis posterior is innervated by the tibial nerve (posterior compartment), so it is intact. Common peroneal nerve injury would also affect the superficial peroneal nerve, causing additional weakness of eversion (peroneus longus and brevis) and wider sensory loss over the dorsum of foot. Sciatic nerve injury would also paralyze hamstrings.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.