After exiting the carpal tunnel, the tendons of the flexor digitorum superficialis and profundus muscles cross the palm and enter fibrous sheaths on the palmar aspect of the digits (Fig. 7.101). These fibrous sheaths: begin proximally, anterior to the metacarpophalangeal joints, and extend to the distal phalanges; are formed by fibrous arches and cruciate (cross-shaped) ligaments, which are attached posteriorly to the margins of the phalanges and to the palmar ligaments associated with the metacarpophalangeal and interphalangeal joints; and hold the tendons to the bony plane and prevent the tendons from bowing when the digits are flexed.