Organization of the extensor complex of the digits

On the basis of 150 dissections the authors show that, on the back of the hand, the tendinous formations ensuring the extension of the fingers can be arranged in four groups of a least two tendons for each finger, excepting the thumb. In the little finger the group comprises a constant tendon, the extensor proper, and two variables, the common extensor and the expansion of the extensor carpi ulnaris. In the index finger the extensor proper and the common extensor nearly always coexist. In the middle finger the great common extensor, sometimes divided, can be accompanied at depth, by an extensor tendon. Finally, in the ring finger, two or three more or less intricate slips are found forming the common extensor. The presence of anastomoses and the numerous slips originating in the tendon-forming band can reduce functional deficiency following the section or rupture of a tendon. On account of these variations the surgeon should operate with caution in tendon transplantations.