Locked middle finger.

By far the commonest cause of " locking " in the finger is stenosing tendovaginitis of the sheaths offiexor tendons as they enter their fibro-osseous canals. The result is the common condition of " trigger " finger. Four other ways in which the finger may get locked have been described: I. The extensor tendon may slip off the head of the metacarpal bone and come to lie in the interdigital cleft. This can happen in rheumatoid arthritis, and rarely may follow trauma. Legouest (I 868) saw one case, Paget (I 875) three, and Marsh (I 896) four (but as Marsh was Paget's assistant, and edited Paget's manuscript, only one of the four may have been his own). Razemon (1930), in a review of the literature, was able to find sixteen traumatic cases (only thirteen. if three of Marsh's patients had been earlier described by Paget). He was able to add one more of his own. Since, cases have been described by Straus (1940), Mouchet (1942) and Meyran (1951). The extensors to the index and middle fingers were most commonly affected, and in all but one case (Becker 1903) the tendon dislocated to the ulnar side. 2. Alldred (1954) described a case in which the capsule of the metacarpo-phalangealjoint of the index finger split transversely, and the proximal part became caught round the base of the metacarpal head, thereby producing an irreducible block to extension. 3. Flatt (1958) described a case of recurrent locking in the metacarpo-phalangeal joint of the index finger, from catching of an abnormal sesamoid on the head of the metacarpal. 4. Langenski#{246}ld (1949) described two cases of recurrent locking in the index finger caused by catching of the collateral ligaments on the head of the metacarpal. He pointed out that Poirier (1889), on purely anatomical grounds, thought this mechanism should be a fairly common cause of " trigger " finger. The literature therefore suggests that, apart from the classical " trigger " finger, locking in the finger is uncommon. For this reason the following five cases are described; all the patients attended the casualty department of one hospital within ten months. Case 1-A retired printer's compositor, aged sixty-seven, was lifting a chair with both hands under the seat when he felt a " click " and a sudden sharp pain in the metacarpo-phalangeal joint of the right middle finger, and found that he was unable to straighten …