Ulnar nerve - cubital tunnel syndrome

Causes

• Entrapment due to thickening of the humeroulnar aponeurotic arcade between the two heads of flexor carpi ulnaris.
• Bulging of the medial collateral ligament of the elbow joint.
• Compression by ganglion, cyst or nerve sheath tumor.
• Entrapment by accessory anconeus epitrochlearis muscle.
• Compression by bony spurs, fibrous bands between medial epicondyle and olecranon, or more distally, by thickened septum between flexor carpi ulnaris and flexor digitorum profundus muscles.
• Direct trauma.
• Compression injury during sleep or anesthesia.

Symptoms & signs

• The clinical presentation is the same as in lesions of ulnar nerve above the elbow.
• The flexor carpi ulnaris muscle might be spared.

Examination

• Ulnar flexion maneuver: A 3-minute elbow and wrist flexion in ulnar deviation produces increased paresthesias in the 4th and 5th fingers.