- Extensor carpi ulnaris muscle
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Extensor carpi ulnaris 
Posterior surface of the forearm. Extensor carpi ulnaris labeled in purple at center right. Latin musculus extensor carpi ulnaris Gray's subject #125 454 Origin Common extensor tendon (lateral epicondyle), ulna Insertion 5th metacarpal Artery ulnar artery Nerve the posterior interosseus nerve, a branch of the radial nerve Actions extends and adducts the wrist Antagonist Flexor carpi ulnaris In human anatomy, the extensor carpi ulnaris is a skeletal muscle located on the ulnar side of the forearm. It acts to extend and adduct at the carpus/wrist.
Being an extensor muscle, extensor carpi ulnaris is on the posterior side of the forearm.
Contents
Origin and insertion
It originates from the lateral epicondyle of the humerus and the posterior border of the ulna, and crosses the forearm to the ulnar (medial) side to insert at the base of the 5th metacarpal.
Extensor carpi ulnaris muscle
Action
The extensor carpi ulnaris extends the wrist, but when acting alone inclines the hand toward the ulnar side; by its continued action it extends the elbow-joint.
The muscle is a minor extensor of the carpus in carnivores, but has become a flexor in ungulates. In this case it is described as ulnaris lateralis.
Innervation
Despite its name, the extensor carpi ulnaris is innervated by the posterior interosseous branch of the radial nerve. It would therefore be paralyzed in an injury to the posterior cord of the brachial plexus.[1]
Additional images
Bones of left forearm. Posterior aspect.
Bones of the left hand. Dorsal surface.
Cross-section through the middle of the forearm.
Posterior surface of the forearm. Deep muscles.
Transverse section across distal ends of radius and ulna.
Transverse section across the wrist and digits.
The mucous sheaths of the tendons on the back of the wrist.
Extensor carpi ulnaris muscleExternal links
References
- ^ Chung, K (1995). BRS: Gross Anatomy.
Moore, K; Agar, A (2002). Essential Clinical Anatomy (2nd ed.). Lippincott.
List of muscles of upper limbs (TA A04.6, GA 4.432) Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major
fascia: Deltoid fascia · Supraspinous fascia · Infraspinous fasciaArm
(compartments)OtherForearm superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris
deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicisOtherHand Lateral volarMedial volarhypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor digiti minimi) · palmaris brevisIntermediateposterior: Extensor retinaculum · Extensor expansion
anterior: Flexor retinaculum · Palmar aponeurosisCategories:- Muscles of the upper limb
- Muscle stubs
- ^ Chung, K (1995). BRS: Gross Anatomy.
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