Ulnar nerve compression at the wrist. Ulnar tunnel syndrome.

Compression neuropathy of the ulnar nerve at the wrist can be caused by several lesions. The most common cause is a carpal ganglion followed by occupational repeated trauma to the hypothenar area. This process is in contrast to carpal tunnel syndrome in which the majority of the cases are idiopathic in nature with no local cause found except for synovitis of the flexor tendons. The site of the lesion will determine the clinical picture whether it is both motor and sensory abnormalities, only motor paralysis or only sensory abnormality. The latter is rare. If the abnormality is purely motor, then the compression is distal in the ulnar tunnel and the hypothenar muscles are usually spared. Carpal ganglia must be sought and removed. After an extensive search through the literature, I found only one report in which thickening of the volar carpal ligament was found to be the cause of ulnar nerve compression. I encourage the use of the term "ulnar tunnel syndrome" to discuss these lesions and the classification outlined by Shea to determine the site of the lesion. Patients with type 2 syndrome usually present late because of the lack of sensory changes. Average delay in obtaining a diagnosis of 5 months was found in my patients. The condition should be suspected if spontaneous clumsiness or awkwardness of the use of the hand occurs in a middle-aged patient.