| Extensor carpi radialis longus |
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| Superficial muscles of the forearm. Extensor carpi radialis longus visible in blue. |
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| Transverse section across the wrist and digits. (Ext. carp. rad. long. labeled at center left.) |
| Latin |
musculus extensor carpi radialis longus |
| Gray's |
subject #125 452 |
| Origin |
lateral supracondylar ridge |
| Insertion |
2nd metacarpal |
| Artery |
radial artery |
| Nerve |
radial nerve |
| Actions |
extensor at the wrist joint, abducts the hand at the wrist |
| Antagonist |
Flexor carpi ulnaris muscle |
Extensor carpi radialis longus is one of the five main muscles that control movements at the wrist. This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the second metacarpal bone (metacarpal of the index finger).
Contents
- 1 Function
- 2 Origin, course, and insertion
- 3 Innervation
- 4 Exercises
- 5 Additional images
- 6 Notes
- 7 References
- 8 External links
Function[edit]
As the name suggests, this muscle is an extensor at the wrist joint and travels along the radial side of the arm, so will also abduct (radial abduction) the hand at the wrist.[1] That is, it manipulates the wrist so as to move the hand towards the thumb (i.e., abduction—away from the mid-position of the hand) and away from the palmar side (i.e., extension—increased angle between the palm and the front of the forearm).
Origin, course, and insertion[edit]
It originates from the lateral supracondylar ridge of the humerus, from the lateral intermuscular septum, and by a few fibers from the lateral epicondyle of the humerus.[1]
The fibres end at the upper third of the forearm in a flat tendon, which runs along the lateral border of the radius, beneath the Abductor pollicis longus and Extensor pollicis brevis; it then passes beneath the dorsal carpal ligament, where it lies in a groove on the back of the radius common to it and the Extensor carpi radialis brevis, immediately behind the styloid process.
One of the three muscles of the radial forearm group, it initially runs along with brachioradialis, but becomes mostly tendon early on. Passing between brachioradialis and extensor carpi radialis brevis, this tendon continues into the second tendon compartment together with the latter muscle.[1]
It is inserted into the dorsal surface of the base of the second metacarpal bone, on its radial side.[1]
Innervation[edit]
The extensor carpi radialis longus is a wrist extensor that is innervated by the radial nerve.[1] Though the radial nerve receives contributions from vertebrae levels C5, C6, C7, C8 and T1, studies have shown that the neurons that innervate the extensor carpi radialis longus arise from cervical vertebrae levels C6 and C7.[2] All other major extensor muscles in the superficial layer of the posterior compartment (the Extensor Digitorum, Extensor Carpi Radialis Brevis, Extensor Carpi Ulnaris, and the Extensor Digiti Minimi) are innervated by the posterior interosseous branch of the radial nerve.
Exercises[edit]
The muscle, like all extensors of the forearm, can be strengthened by exercise that resist its extension. A wrist roller can be used and reverse wrist curls with dumbbells can performed.
Additional images[edit]
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Bones of left forearm. Posterior aspect.
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Bones of the left hand. Dorsal surface.
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Tendons of forefinger and vincula tendina.
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Cross-section through the middle of the forearm.
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Posterior surface of the forearm. Deep muscles.
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Transverse section across distal ends of radius and ulna.
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The mucous sheaths of the tendons on the back of the wrist.
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Extensor carpi radialis longus muscle
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Extensor carpi radialis longus muscle
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Extensor carpi radialis longus muscle
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Extensor carpi radialis longus muscle
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Extensor carpi radialis longus muscle
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Muscles of upper limb. Cross section.
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Notes[edit]
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This article relies largely or entirely upon a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. (August 2009) |
- ^ a b c d e Platzer 2004, p 164
- ^ Bradley Bowden, Illustrated Atlas of the Skeletal Muscles, 2005
References[edit]
- Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.
External links[edit]
- -1912209407 at GPnotebook
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List of muscles of upper limbs (TA A04.6, GA 4.432)
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| Shoulder |
deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major
fascia: deltoid fascia · supraspinous fascia · infraspinous fascia
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Arm
(compartments) |
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anterior
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coracobrachialis · biceps brachii · brachialis
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posterior
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triceps brachii · anconeus · articularis cubiti
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fascia
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axillary sheath · axillary fascia · brachial fascia · intermuscular septa (lateral, medial)
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other
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spaces (quadrangular space, triangular space, triangular interval)
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| Forearm |
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anterior
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superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis
deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus
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posterior
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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 indicis
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fascia
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bicipital aponeurosis · common tendons (extensor, flexor) · antebrachial fascia
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other
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cubital tunnel
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| Hand |
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lateral volar
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thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis
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medial volar
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hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor digiti minimi) · palmaris brevis
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intermediate
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lumbrical · interossei (dorsal, palmar)
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fascia
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posterior: extensor retinaculum · extensor expansion
anterior: flexor retinaculum · palmar aponeurosis
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anat (h/n, u, t/d, a/p, l)/phys/devp/hist
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noco (m, s, c)/cong (d)/tumr, sysi/epon, injr
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