Nerve affected by cubital tunnel syndrome?

• A. Median nerve
• B. Radial nerve
• C. Axillary nerve
• D. Ulnar nerve

Answer: (D)

Cubital tunnel syndrome involves compression of the ulnar nerve as it travels through the cubital tunnel, a groove behind the medial epicondyle of the humerus. This position makes the ulnar nerve especially vulnerable to irritation with elbow flexion or repetitive stress. The ulnar nerve supplies most intrinsic hand muscles (such as the interossei and the medial two lumbricals) and provides sensation to the little finger and the medial half of the ring finger. When compressed at the elbow, symptoms reflect this distribution: numbness or tingling in the little finger and half of the ring finger, and weakness in finger spreading and fine hand movements. Other nerves have different anatomical courses and injury sites—the median nerve travels toward the forearm and carpal tunnel, the radial nerve runs in the radial groove and forearm, and the axillary nerve supplies the deltoid/teres minor around the shoulder—so their involvement would present with different patterns of sensory and motor loss. Thus, the nerve affected by cubital tunnel syndrome is the ulnar nerve.