ENCAPSULATED LIPOMA OF THE MEDIAN NERVE AT THE WRIST.

A married woman aged forty-two said that since childhood she had noticed slight swelling in front of the left lower forearm just above the wrist which had increased in size in recent years. For two years there had been a tendency to numbness of the index and middle fingers but only after strenuous household work. Clinical examination showed a soft, doughy semi-fluctuant swelling in the midline of the lower forearm in the position of the common sheath of flexores digitorum, one inch in width, extending three inches proximally from the level of the flexor retinaculum of the wrist. There was no swelling in the palm but there seemed to be transmitted fluctuation when pressure was applied over the swelling above the retinaculum. Movements of the fingers and wrist were normal. There was slight impairment of pain and touch sensation in the distribution of the median nerve, shown only by uncertainty of response to fine hair touch as opposed to more coarse touch in the palmar surfaces of index and middle fingers, and dulling of pain in the palmar surface of the thumb. There was no loss of power, or wasting of the thenar muscles or other intrinsic muscles of the hand. The circulation was normal and there were no trophic changes. Radiographic examination showed no evidence of bone abnormality in the carpus, wrist, radius or ulna. A diagnosis was made ofchronic tenosynovitis or “ compound palmar ganglion “ with minimal involvement of the palmar part of the sheath so tense from synovial thickening as to cause median nerve irritation.