A patient sustains a deep laceration in the axilla that severs the musculocutaneous nerve. Which combination of findings would be expected?

• A Wrist drop with intact elbow flexion and numbness over the anatomical snuffbox
• B Weak elbow flexion, weak forearm supination, absent biceps jerk, numbness over the lateral forearm ✓
• C Clawing of ring and little fingers with numbness over the medial two digits
• D Loss of shoulder abduction with numbness over the regimental badge area

Explanation

The musculocutaneous nerve pierces coracobrachialis and supplies biceps brachii and brachialis, so its division weakens elbow flexion and active supination (biceps is a strong supinator) and abolishes the biceps jerk. It continues as the lateral cutaneous nerve of the forearm, giving sensory loss over the lateral forearm. Option A describes a radial nerve lesion, C an ulnar lesion, and D an axillary nerve lesion.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.