A young man sustains a deep laceration on the anterior aspect of his mid right arm. He has profound weakness of elbow flexion, an absent biceps jerk, and numbness along the lateral surface of the forearm down to the wrist. Which nerve has been injured?

• A Median nerve
• B Axillary nerve
• C Radial nerve
• D Musculocutaneous nerve ✓

Explanation

The musculocutaneous nerve supplies coracobrachialis, biceps brachii and brachialis, then continues past the elbow as the lateral cutaneous nerve of forearm. The combination of lost elbow flexion, absent biceps jerk and lateral forearm numbness fits this nerve alone. The median nerve does not supply the biceps or carry lateral forearm sensation, which eliminates the most tempting distractor.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.