Cubital Tunnel Syndrome: Ulnar Nerve Compression at the Elbow

Cubital tunnel syndrome — compression of the ulnar nerve at the elbow — is the second most common nerve entrapment neuropathy after carpal tunnel syndrome. The ulnar nerve passes through the cubital tunnel (a narrow passage behind the medial epicondyle of the elbow — the "funny bone") where it is vulnerable to pressure and stretch.

Symptoms and Pattern

The ulnar nerve supplies the little finger and the medial half of the ring finger, plus the intrinsic muscles of the hand (except the thenar eminence). Compression causes: tingling and numbness in the little finger and ring finger (the ulnar 1.5 fingers); pain along the inner aspect of the elbow; worsening with prolonged elbow flexion (holding the phone to the ear, sleeping with the arm bent at the elbow); in advanced cases — weakness of hand grip, loss of pinch strength (the flexor digitorum profundus to the ring and little fingers is affected), clawing of the ring and little fingers (intrinsic minus hand), and wasting of the first dorsal interosseous muscle (the muscle between the thumb and index finger on the back of the hand — a visible sign of ulnar nerve damage).

Diagnosis

Froment's sign: ask the patient to hold a piece of paper between the thumb and index finger — in ulnar palsy, the thumb interphalangeal joint flexes (using flexor pollicis longus to compensate for weak adductor pollicis). Nerve conduction studies confirm the site and degree of ulnar nerve slowing at the elbow.

Treatment

Conservative: elbow padding; avoid leaning on the elbow; elbow extension splint at night (prevents the prolonged flexed position that stretches the nerve during sleep). Surgical: ulnar nerve decompression (releasing the roof of the cubital tunnel) or ulnar nerve transposition (moving the nerve to the front of the elbow) — for severe or non-responding cases. Sri Anand CNC, Chanda Nagar, Hyderabad. Call +91 90633 66983.