Flexor carpi ulnaris

Jacob Lau and Dr Henry Knipe et al.

Flexor carpi ulnaris (FCU) is a muscle of the first layer of the anterior compartment of the forearm. It is one of the extrinsic muscles of the hand.


  • origin
    • humeral head: medial epicondyle of the humerus
    • ulnar head: aponeurosis from medial olecranon and upper three quarters subcutaneous border of ulna
  • insertion: base of 5th metacarpal; hook of hamate, pisiform
  • arterial supply: posterior ulnar recurrent artery and ulnar artery
  • innervationulnar nerve (C8-T1)
  • action: flexion and adduction of the wrist joint
  • pathology: calcific tendinitis which occurs at the insertion into pisiform
  • variability: muscle can be doubled - accessory flexor carpi ulnaris, which can be often accompanied by concomitant variants 3
Anatomy: Upper limb

Anatomy: Upper limb

Article information

rID: 23257
Section: Anatomy
Synonyms or Alternate Spellings:
  • FCU
  • Flexor carpi ulnaris muscle

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