ABSTRACT
MUSCLES AND TENDONS n Flexion of the fingers and thumb is powered by exor digitorum profundus (FDP), exor
digitorum supercialis (FDS), and exor pollicis longus (FPL) muscles. • FDS tendons have a common muscle belly at the forearm level. Each FDP tendon has its
own individual muscle belly at the forearm level. • Each FDS tendon divides into two equal halves at the level of the metacarpal head (Camper’s
chiasma). Each half rotates laterally and dorsally around the FDP tendon. FDS slips rejoin deep (dorsal) to the FDP tendon at the distal end of the proximal
phalanx1 (Fig. 69-1). FDS then inserts on volar aspect of middle phalanx as two separate slips. Small finger FDS tendon may be diminutive or completely absent.7
