History and Physical Examination

A 36-year-old, right-hand–dominant secretary presents with a 1-year history of progressive tingling in the small finger and the ulnar side of the ringfinger. She also reports mild clumsiness of the hand, making her job as a secretary somewhat difficult. She denies any specific traumatic event and has received no treatment todate.

Careful neurovascular examination of the affected extremity demonstrates no abnormalities except for 4/5 ulnar intrinsic motor function and slightly decreasedsensation in the ulnar distribution of the hand. Range of motion of the wrist, elbow, and shoulder is normal. There is no palpable bony tenderness in the hand or wrist. A positive Tinel’s sign is present for the ulnar nerve at the cubital tunnel of the elbow but not at Guyon’s canal. Also, through a range of motion of the elbow, the ulnar nerve can be seen to sublux anteriorly over the medial epicondyle. The distal radial and ulnar pulses are intact and the patient has a negative Allen’s test.

Differential Diagnosis

1. Ulnar neuropathy of the elbow

2. Carpal tunnel syndrome

3. Valgus instability of the elbow

4. Cervical radiculopathy

5. Ulnar nerve entrapment at Guyon’s canal

6. Ulnar artery thrombosis in Guyon’s canal

7. Hook of the hamate fracture

Radiologic Findings

Anteroposterior (AP) and lateral views of the elbow, and AP, lateral, and carpal tunnel views of the wrist are normal.

Diagnosis

Ulnar Neuropathy of the Elbow Secondary to Ulnar Nerve Instability and Subluxation. The diagnosis of ulnar neuropathy at the elbow is fairly straightforward in this case because of the subluxatable and very symptomatic ulnar nerve at the elbow. The diagnosis is not often as easily established because of a number of pathologic conditions that can simulate ulnar neuritis at the elbow. Patients with ulnar neuropathy may present with insidious or acute complaints. Their symptoms are usuallyrelated to paresthesias in the ulnar half of the ring and small finger, often awakening the patient at night. Alternatively, the presenting complaint may be an aching or lancinating pain centered over the medial epicondyle. Sensory complaints generally precede motor symptoms in ulnar neuropathy at the elbow. A job with repetitive elbow motion, such as assembly work or overhead sports, may predispose to symptoms.