The interosseous muscles are flexor muscles of the manus that help support and flex the metacarpophalangeal joints. In some species the muscles are known as the suspensory ligaments. The muscles are found under the deep digital flexor tendon and originate from the base of each metacarpal bone. From its origin each muscle runs a short way down until it divides into two tendons that continue down and insert onto the base of its corresponding proximal phalanx. Each tendon has a sesamoid imbedded within it, that lie over the metacarpophalangeal joint. A small tendon, sometimes known as an extensor branch, continues to proceed from the base of each proximal phalanx and connects to the common extensor tendon. It has a small role to play in the extension of each phalanx. The main innervation of this muscle is via a branch of the ulnaris nerve[MURDOCH:1022].

uberon

UBERON:0001502