The flexor digitorum superficialis is an extrinsic muscle that enables the 4 medial fingers of the hand to flex. These fingers embrace the index, center, ring, and pinkie fingers. The time period extrinsic signifies that the muscle is positioned within the forearm. This muscle has two distinct heads, which each originate within the forearm. The humeroulner head originates on the medial epicondyle of humerus, which refers to a knuckle-like projection on the a part of the higher arm bone that’s closest to the elbow. This head additionally originates from the ulnar collateral ligament and coronoid strategy of ulna, which refers to a triangular projection on the ulna. The ulna is among the bones of the forearm. The opposite head, referred to as the radial head, originates from the again portion of the radius, a bone of the forearm. 4 tendons come up from this muscle near the wrist and move through the carpal tunnel. The tendons break up and insert on the edges of the center phalanges of the 4 medial fingers. In lots of instances, the tendon is absent from the little finger. This is called an anatomical variant. In flip, this will likely lead to issues with the prognosis of an damage of the little finger. Every of the 4 medial fingers incorporates three bones. These are the distal phalanges on the fingertips, the center phalanges, and the proximal phalanges that are closest to the palm. The first motion of the flexor digitorum superficialis is to flex the fingers on the proximal interphalangeal joints. These hinge joints are positioned between the between the center and proximal phalanges. The secondary function of the muscle is to flex the metacarpophalangeal joints. These are positioned between the proximal phalanges and the metacarpal bones of the palm.
The muscle receives oxygen-rich blood from the ulnar artery. It’s innervated by the median nerve.