The anterior muscles of the forearm consist of three layers, the superficial, intermediate, and deep flexors. All three layers are located in the flexor compartment.

Among the superficial muscles is the flexor carpi ulnaris. It arises, along with the other superficial muscles, from the medial epicondyle of the humerus. But the flexor carpi ulnaris muscle has an additional attachment point on the head of the ulna. It inserts at two wrist bones: the pisiform bone and the hook of the hamate. It also inserts at the base of the pinky finger.

Blood is supplied to the muscle by the ulnar collateral arteries and the anterior and posterior ulnar recurrent arteries. It also receives blood from small branches of the ulnar artery. The flexor carpi ulnaris is enervated by the ulnar nerve.

The flexor carpi ulnaris muscle works in tandem with the extensor carpi ulnaris. These muscles flex the wrist and adduct it (move it laterally in the direction of ulnar).