Wikipedia

Flexor carpi ulnaris muscle

Theflexor carpi ulnaris(FCU) is amuscleof theforearmthatflexesandadductsat the wrist joint.

Flexor carpi ulnaris
Dorsal (left) and ventral (right) views of deep muscles of the left forearm. The flexor carpi ulnaris muscle is in blue.
Details
OriginMedial epicondyle(common flexor tendon) and medial margin onolecranonofulna
InsertionPisiform,hook of the hamate,base of thefifth metacarpal bone(volar aspect)
ArteryUlnar artery
NerveMuscular branches of ulnar nerve(fromC8andT1)
ActionsFlexionand adduction ofwrist
AntagonistExtensor carpi radialis brevis muscleandextensor carpi radialis longus muscle
Identifiers
Latinmusculus flexor carpi ulnaris
TA98A04.6.02.030
TA22483
FMA38465
Anatomical terms of muscle

Structure

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Origin

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The flexor carpi ulnaris has two heads; a humeral head and ulnar head. The humeral head originates from the medial epicondyle of the humerus via the common flexor tendon. The ulnar head originates from the medial margin of the olecranon of the ulna and the upper two-thirds of the dorsal border of the ulna by an aponeurosis. Between the two heads passes the ulnar nerve and ulnar artery.

Insertion

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The flexor carpi ulnaris inserts onto thepisiform,hook of the hamate (via thepisohamate ligament) and the anterior surface of the base of thefifth metacarpal(via thepisometacarpal ligament).[1]

Action

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The flexor carpi ulnaris flexes and adducts at thewrist joint.[2]

Innervation

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The flexor carpi ulnaris is innervated by theulnar nerve.The corresponding spinal nerves areC8andT1.

Tendon

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The tendon of flexor carpi ulnaris can be seen on the anterior surface of the distal forearm. On a person's distal forearm, just before the wrist, there are either two or three tendons. The tendon of the flexor carpi ulnaris is the most medial (closest to the little finger) of these. The most lateral one is the tendon offlexor carpi radialis muscle,and the middle one, not always present, is the tendon ofpalmaris longus.

Function

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The muscle, like all flexors of the forearm, can bestrengthenedby exercises that resist its flexion. Awrist rollercan be used andwrist curlswithdumbbellscan also be performed. These exercises are used to prevent injury to theulnar collateral ligament of elbow joint.[citation needed]

Variability

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The muscle can be doubled as accessory flexor carpi ulnaris muscle and is often accompanied by concomitant variants.[3]

Clinical significance

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Ulnar entrapment by the aponeurosis of the two heads of the flexor carpi ulnaris muscle may causecubital tunnel syndrome.

The tendon of flexor carpi ulnaris can be used fortendon transfer.[3]

Additional images

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  • Bones of left forearm. Posterior aspect.
  • Bones of the left hand. Volar surface showing its insertion into thepisiformbone and then vialigamentsinto thehamatebone and 5thmetacarpalbone, acting to flex and adduct the wrist joint.
  • Cross-section through the middle of the forearm.
  • Flexor carpi ulnaris muscle

References

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  1. ^Maroukis, Brianna L.; Ogawa, Takeshi; Rehim, Shady A.; Chung, Kevin C. (March 2015)."Guyon canal: the evolution of clinical anatomy".The Journal of Hand Surgery.40(3): 560–565.doi:10.1016/j.jhsa.2014.09.026.ISSN1531-6564.PMC4791630.PMID25446410.
  2. ^Chaudhry, Fatima; Ahmad, Haroon; Sinkler, Margaret A.; Arain, Abdul (2024),"Anatomy, Shoulder and Upper Limb, Forearm Compartments",StatPearls,Treasure Island (FL): StatPearls Publishing,PMID30969606,retrieved2024-08-21
  3. ^abKunc, Vojtech; Stulpa, Michal; Feigl, Georg; Kachlik, David (2019-05-29). "Accessory flexor carpi ulnaris muscle with associated anterior interosseous artery variation: case report with the definition of a new type and review of concomitant variants".Surgical and Radiologic Anatomy.41(11): 1315–1318.doi:10.1007/s00276-019-02261-4.ISSN0930-1038.PMID31144008.S2CID169032218.
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