1. Rheumatoid tenosynovitis is a common complication of rheumatoid arthritis. Its slow, non-painful development often results in failure of recognition and diagnosis.

2. This lesion is found most commonly on time dorsum of the wrist, involving the extensor tendons. Diagnosis can be established only by histological examination of the diseased tissue. It can be suspected when swelling appears in and upon the tendons in the presence of rheumatoid arthritis.

3. Treatment in the early stage should include heat, support, and relaxation of the tendon. It may be supplemented by injections of hydrocortisone into the mass every two weeks. When the swelling becomes large, excision of the diceased tissue as completely as possible is advised. Rupture of tendons requires surgical repair.

4. In early tenosynovitis, rest and heat resulted in complete relif in 46 per cent of the Patients. In masses less than one inch in diameter injections of hydrocortisone led to rapid disappearance of the mass in 43 per cent. Excision of masses greater than one inch in diameter resulted in cures in 66 per cent. Tendon repairs led to good function in 44 per cent.

5. No relationship could be established between rheumatoid tenosynovitis and de Quervain's disease and snapping-finger.