Nerve injured with fracture of the medial humeral epicondyle?

• A. Median
• B. Ulnar
• C. Radial
• D. Musculocutaneous

Answer: (B)

When the medial humeral epicondyle is fractured, the nerve most at risk is the one that runs in the groove just behind this bump—the ulnar nerve. It travels in the ulnar groove at the elbow (the cubital tunnel) right posterior to the medial epicondyle, making it particularly vulnerable to injury from trauma to this area. If damaged there, its motor supply to most intrinsic hand muscles (via the deep branch) and its sensory supply to the medial one-and-a-half fingers can be affected, leading to weakness in finger abduction/adduction and numbness on the inner edge of the hand.

The other nerves follow different courses around the elbow and are less likely to be injured by a fracture at the medial epicondyle: the median nerve travels anteriorly into the forearm and then the hand; the radial nerve runs posteriorly around the humerus and around the lateral elbow; the musculocutaneous nerve stays in the anterior compartment of the arm.