Levator scapulae muscle: Difference between revisions
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{{Infobox muscle |
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| Name = Levator scapulae muscle |
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| Latin = musculus levator scapulae |
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| GraySubject = 121 |
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| GrayPage = 435 |
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| Image = Levator scapulae.png |
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| Caption = Muscles connecting the upper extremity to the [[vertebral column]]. (Levator scapula visible at upper right, at the neck.) |
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| Image2 = Muscle élévateur de la scapula.png |
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| Caption2 = Muscles of neck. (Levator scapula visible at center left.) |
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| Origin = [[Posterior tubercles]] of [[transverse processes]] of C1 - C4 vertebrae |
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| Insertion = Superior part of [[medial border of scapula]] |
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| Blood = [[dorsal scapular artery]] |
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| Nerve = [[cervical nerve]] (C3, C4) and [[dorsal scapular nerve]] (C5) |
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| Action = [[Elevation (kinesiology)|Elevates]] [[scapula]] and tilts its [[glenoid cavity]] inferiorly by rotating scapula |
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| DorlandsPre = m_22 |
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| DorlandsSuf = 12549630 |
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}} |
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In human anatomy, the '''levator scapulae''' ({{IPAc-en|ˌ|l|ɨ|'|v|eɪ|t|ər|_|'|s|k|æ|p|j|ʉ|l|iː|}}) is a [[skeletal muscle]] situated at the back and side of the neck. As the Latin name suggests, its main function is to lift the [[scapula]]. |
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==Human anatomy== |
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===Origin and insertion=== |
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The levator scapulae originates from the dorsal [[tubercle]]s of the [[transverse processes]] of [[cervical vertebrae]] one to four. The muscle is inserted into medial border of the scapula extending from superior angle to junction of spine and medial border of scapula |
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<ref name="Platzer">{{harvnb|Platzer|2004| p=144}}</ref> |
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The levator scapulae may lie deep to the [[sternocleidomastoideus]] at its origin, deep or adjacent to the [[splenius capitis]] at its origin and mid-portion, and deep to the [[trapezius]] in its lower portion. |
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===Actions=== |
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When the spine is fixed, levator scapulae elevates the scapula and rotates its [[Inferior angle of the scapula|inferior angle]] medially.<ref name="Platzer" /> It often works in combination with other muscles like the [[rhomboid muscles|rhomboids]] and [[pectoralis minor]] to rotate down. |
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Elevating or rotating one shoulder at a time would require muscles to stabilize the cervical spine and keep it immobile so it does not flex or rotate. Elevating both at once with equal amounts of pull on both side of cervical spinal origins would counteract these forces. Downward rotation would be prevented by co-contraction of other muscles that elevate the spine, the upper fibers of the trapezius, which is an upward rotator. |
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When the shoulder is fixed, levator scapula rotates and flexes the cervical spine laterally.<ref>{{Exrx|Muscles/LevatorScapulae}}</ref> When both shoulders are fixed, a simultaneous co-contraction of both levator scapulae muscles in equal amounts would not produce lateral flexion or rotation, and may produce straight flexion or extension of the cervical spine. |
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===Relations=== |
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One of the muscles within the floor of the [[posterior triangle of the neck]], the superior part of levator scapula is covered by [[Sternocleidomastoid muscle|sternocleidomastoid]] and its inferior part by the [[Trapezius muscle|trapezius]]. |
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<ref>{{GPnotebook|-154140595}}</ref> |
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It is bounded in front by the [[scalenus medius]] and behind by [[splenius cervicis]]. The [[spinal accessory nerve]] crosses laterally in the middle part of the muscle and the [[dorsal scapular nerve]] may lie deep to or pass through it. |
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<ref name="Rockwood-2009">{{harvnb|Rockwood|Matsen|Lippitt|Wirth|2009| p=55}}</ref> |
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===Variations=== |
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The number of vertebral attachments varies; a slip may extend to the occipital or mastoid, to the [[trapezius]], [[scalene muscles|scalene]] or [[serratus anterior]], or to the first or second rib. The muscle may be subdivided into several distinct parts from origin to insertion. Levator claviculæ from the transverse processes of one or two upper cervical vertebræ to the outer end of the clavicle corresponds to a muscle of lower animals. More or less union with the serratus anterior. |
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<ref name="Gray's-1918">''[[Gray's Anatomy]]'' (1918), see infobox</ref> |
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===Innervation and blood supply=== |
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The levator scapulae is supplied by two or three branches of the fourth and fifth [[cervical nerves]],<ref name="Platzer" /> and frequently by a branch from the [[Dorsal scapular nerve|dorsal scapular]].<ref name="Gray's-1918" /> |
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The levator scapulae is supplied by the [[dorsal scapular artery]]. Normally, this artery has a small branch which passes laterally to the [[Supraspinatous fossa|supraspinatus fossa]] of the scapula, and in a third of cases, this branch supplies the muscle. If the dorsal scapular artery comes off the transverse cervical artery, the parent transverse cervical artery splits, the dorsal scapular artery passes medially, while the transverse cervical artery passes laterally. |
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<ref name="Rockwood-2009" /> |
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==Evolutionary variation== |
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The muscles of the shoulder can be categorized into three topographic units: the scapulohumeral, axiohumeral, and axioscapular groups. Levator scapulae forms part of the latter group together with rhomboid major, rhomboid minor, serratus anterior, and trapezius. The trapezius evolved separately, but the other three muscles in this group evolved from the first eight or ten ribs and the transverse processes of the cervical vertebrae (homologous to the ribs). The serratus anterior formed the basal unit for these three muscles. In higher primates it has evolved into two separate muscles — serratus anterior and levator scapulae — by concentration of the proximal and distal fibers and progressive reduction of the intermediate fibers. The fibers concerned with the cranial displacement of the scapula became the levator scapulae. |
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<ref name="Brand-2008">{{harvnb|Brand|2008| pp=540–41}}</ref> |
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==Additional images== |
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<gallery> |
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File:Levator scapulae muscle animation small2.gif|Position of levator scapulae muscle. |
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File:Gray84.png|A cervical vertebra |
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File:Gray85.png|Side view of a typical cervical vertebra |
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File:Gray203.png|Left scapula. Dorsal surface. |
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File:Gray384.png|Section of the neck at about the level of the sixth cervical vertebra. |
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File:Gray385.png|Muscles of the neck. Lateral view. |
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File:Gray794.png|Hypoglossal nerve, cervical plexus, and their branches. |
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File:Gray808.png|The right brachial plexus with its short branches, viewed from in front. |
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File:Anterior region of neck.JPG|Levator scapulae muscle |
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File:Slide1cord.JPG|Brachial plexus. Deep dissection. |
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File:Slide1ecc.JPG|Brachial plexus. Deep dissection. Anterolateral view |
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</gallery> |
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==See also== |
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{{Commonscat|Levator scapulae muscles}} |
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* [[Levator claviculae muscle]] |
* [[Levator claviculae muscle]] |
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* [[Stiff neck]] - most commonly caused by pain in the Levator scapulae |
* [[Stiff neck]] - most commonly caused by pain in the Levator scapulae |
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==Notes== |
==Notes== |
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{{Gray's}} |
{{Gray's}} |
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==References== |
==References== |
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*<!--Brand --> {{Cite journal | last1 = Brand | first1 = R. A. | title = Origin and Comparative Anatomy of the Pectoral Limb | doi = 10.1007/s11999-007-0102-6 | journal = Clinical Orthopaedics and Related Research | volume = 466 | issue = 3 | pages = 531–42 | year = 2008 | pmid = |
*<!--Brand --> {{Cite journal | last1 = Brand | first1 = R. A. | title = Origin and Comparative Anatomy of the Pectoral Limb | doi = 10.1007/s11999-007-0102-6 | journal = Clinical Orthopaedics and Related Research | volume = 466 | issue = 3 | pages = 531–42 | year = 2008 | pmid = |
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| isbn = 978-1-4160-3427-8 |
| isbn = 978-1-4160-3427-8 |
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| url = http://books.google.com/books?id=7ca8iqAPo2UC&pg=PA55 |
| url = http://books.google.com/books?id=7ca8iqAPo2UC&pg=PA55 |
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| ⚫ | |||
}} |
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{{Muscles of thorax and back}} |
{{Muscles of thorax and back}} |
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Revision as of 15:11, 18 February 2016
- Levator claviculae muscle
- Stiff neck - most commonly caused by pain in the Levator scapulae
Notes
This article incorporates text in the public domain from page 435 of the 20th edition of Gray's Anatomy (1918)
References
- Brand, R. A. (2008). "Origin and Comparative Anatomy of the Pectoral Limb". Clinical Orthopaedics and Related Research. 466 (3): 531–42. doi:10.1007/s11999-007-0102-6. PMC 2505211. PMID 18264841.
- Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.
{{cite book}}: Invalid|ref=harv(help) - Rockwood, Charles A.; Matsen, Frederick A.; Lippitt, Steven B.; Wirth, Michael A. (2009). The shoulder, Volume 1. Elsevier. ISBN 978-1-4160-3427-8.
{{cite book}}: Invalid|ref=harv(help)