Flexor carpi ulnaris muscle (anatomy)

Flexor carpi ulnaris is one of the muscles of the anterior aspect of the forearm.

It originates from two sites:

• humeral head from the common flexor origin on the medial epicondyle of the humerus
• ulnar head from the medial border of the olecranon via an aponeurosis and from the proximal half of the subcutaneous posterior border of the ulna

It passes distally and radially. It inserts into the pisiform bone but indirectly acts upon the hamate bone and fifth metacarpals via the pisohamate ligament and pisometacarpal ligament respectively.

The actions of flexor carpi ulnaris are:

• adduction (ulnar deviation) of the hand at the wrist
• flexion of the hand at the wrist
• fixes the pisiform bone during hypothenar muscle activity

It is innervated by the ulna nerve (C6, C7).