Ulnar Neuropathy

Key Features

• Occurs commonly in the elbow where the nerve runs behind the medial epicondyle and descends into the cubital tunnel

• In the condylar groove, the ulnar nerve is exposed to pressure or trauma

• Any increase in the carrying angle of the elbow, whether congenital, degenerative, or traumatic, may cause excessive stretching of the nerve when the elbow is flexed

• May also result from thickening or distortion of the anatomic structures forming the cubital tunnel, and the resulting symptoms may be aggravated by flexion of the elbow because the tunnel is then narrowed by tightening of its roof or inward bulging of its floor

• May also develop at the wrist or in the palm of the hand, usually owing to repetitive trauma or to compression from ganglia or benign tumors

Clinical Findings

• Sensory changes in the fifth and medial half of the fourth digits and along the medial border of the hand

• Weakness of the ulnar-innervated muscles in the forearm and hand

• With a cubital tunnel lesion, there may be relative sparing of the flexor carpi ulnaris muscle

• Lesions at the wrist or palm cause weakness, sensory deficits, or both, restricted to the hand

Diagnosis

• Electrophysiologic evaluation using nerve stimulation techniques allows precise localization of the lesion

Treatment

• Initial treatment

  • Avoid pressure on the medial elbow (eg, avoid resting the elbows on arm rests; pad the elbow during sleep)

  • Prevent prolonged elbow flexion, especially at night; splints are available to keep the elbow from flexing beyond 45 to 90 degrees

• If repetitive mechanical trauma is responsible, this is avoided by occupational adjustment or job retraining

• If conservative measures are unsuccessful in relieving symptoms and preventing further progression, surgical treatment consists of nerve transposition if the lesion is in the condylar groove or a release procedure if it is in the cubital tunnel