REIDER PART 1
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120_Chaptur 4_Hand and Wrist

Figurę 4-27, cont'd. F, Extensor pollicis longus rupture. G, Extcnsor digitorum communis rupture (ring and littlc fingers).

F    G

Rheumatoid arthritis may also produce ruptures of the extensor digitorum communis tendons. These ruptures produce a flexion deformity of the involved metacar-pophalangeal joints because the paticnt is still able to extend the interphalangeal joints using the intrinsic mus-cles of the hand (see Fig. 4—27G). The cxtensor slip to the little finger is usually the first to rupture, followed pro-gressively by the tendons to the ring, long, and index fingers over a variable period of time. This progressive series of extensor tendon ruptures is known as the Vaughan-Jackson lesion.

Rupture of flexor tendon can also occur, but this is much rarer. These tendons usually rupture with rheumatoid synovitis of the tendons and destruction of the carpal bones. The first tendon to rupture is the flexor pollicis longus; the ruptures then progress in an ulnar direc-tion. This progressive series of flexor tendon ruptures is known as the Mannifelt lesion.

Rotational Malalignment. After examining the extended fingers in pronation and supination for angular deformities, the finger alignment can be further assessed by asking the patient to supinate the hand and loosely flex the fingers together. The examiner begins by inspecting the fingertips end-on while the fingers arc partly flexed. When viewed from this perspective, the fiat of the nail of the index finger faces slightly away from that of the long finger while the nails of the ring finger and the little finger are slightly rotated in the opposite direction (Fig. 4-28). Deviations from this alignment are most com-monly due to rotational deformity following acute frac-ture or malunion of a phalangeal fracture.

The examiner can further test the rotational alignment of the fingers and metacarpals by asking the patient to individually flex each of the four fingers toward the palm. When flexed individually, each finger should face the scaphoid tubercle at the base of the thumb

Figurę 4-28. Normal fingertip alignment.