Upper limb

Flexor Carpi Ulnaris

Musculus flexor carpi ulnaris

Origin

Medial epicondyle of the humerus (humeral head) and olecranon/posterior border of the ulna (ulnar head)

Insertion

Pisiform bone, with extensions to the hamate bone and the base of the fifth metacarpal bone

Function

Flexes the wrist and moves it into ulnar deviation

Innervation

Ulnar nerve, C7–C8(T1)

Movement & chain

Forms a functional pair with extensor carpi ulnaris for pure ulnar deviation; important during throwing and striking movements in which the wrist is held stable in slight flexion.

Palpation

Follow the tendon on the ulnar side of the wrist to the pisiform bone; well palpated with resisted flexion combined with ulnar deviation.

Clinical

The ulnar nerve runs just beneath this muscle through the sulcus for the ulnar nerve; compression here (for example in the cubital tunnel) can cause loss of function of the muscle.

Segmental innervation

Part of the C8–T1 myotome via the ulnar nerve; useful for localizing a high ulnar nerve lesion, for example at the level of the elbow.

In clinical practice

The pisiform bone, onto which this muscle inserts, is a landmark for locating the Guyon's canal when palpating the wrist.

Region in the model

Upper limb