Author: Adrian Rad BSc (Hons)•Reviewer: Roberto Grujičić MDLast reviewed: September 09, 2021Reading time: 6 minutes


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The rhomboids are 2 bilateral, superficial muscles located in the top back. They consist of two functionally similar muscles called rhomboid minor and also rhomboid major. Together via trapezius, levator scapulae and latissimus dorsi, they consist of the superficial layer of the extrinsic back muscles.

You are watching: The actions of the rhomboid major on the scapula do not include __________.

The rhomboid muscles extfinish in between the nuchal ligament, spinous procedures of thoracic vertebrae and also scapula. Under innervation from the dorsal scapular nerve, the rhomboids primarily retract the scapula superomedially and also turn the glenoid cavity. Thus, the rhomboids are necessary to stabilize the scapula into position and also reinforce the shoulder.

This post will comment on the anatomy and also function of the rhomboid muscles.

Key facts around the rhomboid muscles
OriginRhomboid minor: Nuchal ligament, Spinous processes of vertebrae C7-T1Rhomboid major: Spinous procedure of vertebrae T2-T5
InsertionRhomboid minor: Root (medial end) of spine of scapulaRhomboid major: Medial border of scapula (from inferior angle to root of spine of scapula)
ActionScapulothoracic joint: Draws scapula superomedially, Rotates glenoid cavity inferiorly; Supports place of scapula
InnervationDorsal scapular nerve (C4-C5)
Blood supplyDorsal scapular artery, deep branch of transverse cervical artery, dorsal branch of upper five or six posterior intercostal arteries

Contents
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Origin and also insertion


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Rhomboid minor is a small, cylindrical muscle that is composed of two layers; dorsal and also ventral. They partially envelop the levator scapulae inferiorly. Rhomboid minor originates from the nuchal ligament and also spinous procedures of the seventh cervical (C7) and initially thoracic (T1) vertebrae. The muscle extends obliquely in an inferolateral direction, to insert right into the base of the medial end of the spine of scapula; the dorsal layer attaches dorsolateral and inferior to levator scapulae while the ventral layer inserts inferomedially to levator scapulae. At the insertion allude of the ventral layer, the fasciae of rhomboid minor and serratus anterior muscles unite. In certain people, a thin muscle dubbed rhomboid occipitalis can extfinish in between rhomboid minor and also the occipital bone.

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Rhomboid significant is a broad quadrilateral muscle that originates from the spinous procedures of the second to second to fifth thoracic vertebrae (T2-T5). The muscle exhas a tendency obliquely in an inferolateral direction to insert right into the medial border of scapula, in between the inferior angle and also root of the spine of scapula. The attachment takes location both on the dorsal and costal facets of the medial border of scapula.

Find Out whatever about the superficial earlier muscles through our video tutorials, quizzes, labeled diagrams, and posts.


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Superficial muscles of the earlier Explore examine unit
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The rhomboid muscles overlie the deep (intrinsic) muscles of the back and also are covered by the trapezius muscle. The exception is a tiny triangular area over the inferior border of rhomboid major (triangle of auscultation). This area is bordered by the latissimus dorsi muscle inferiorly, trapezius muscle superomedially and rhomboid significant superolaterally. It is a crucial clinical landnote that serves for lung auscultation from the ago.

The rhomboids are mainly totally sepaprice muscles, but they have the right to be foffered in particular individuals. Rhomboid minor partly overlaps the superior percent of rhomboid significant.

Innervation

Both rhomboid muscles are innervated by the dorsal scapular nerve (C4-C5), a branch of the brachial plexus.

Blood supply

Rhomboid minor and major receive arterial blood from three sources:


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Function

The major activity of the rhomboid muscles is scapular retraction about the scapulothoracic joint. Scapular retractivity is a simultaneous sliding of the scapula superiorly and also medially along the trunk. This superomedial motion of the scapula rotates the glenoid cavity inferiorly, dropping the shoulder girdle. By opposing too much scapular protractivity, the rhomboids help to maintain a correct posture once sitting, standing and walking. 

In enhancement, the contraction of the rhomboids fixes and stabilizes the scapula into position. This provides an anchor allude in space from which miscellaneous muscles of the top limb can act and also a fulcrum roughly which the upper limb can relocate.

Take the adhering to quiz to test your knowledge on the rhomboids, and other superficial muscles of the back!


Clinical relations

The rhomboid muscles have the right to have actually a great impact on upper body posture and also shoulder mechanics. Poor top body posture frequently contains a variety of features. One is that the shoulders, and also especially the scapulae, tend to end up being protracted. This will often bring about pain in the upper back, particularly alengthy the medial border of the scapulae. Therefore, strengthening muscles responsible for scapular retraction, such as the rhomboids, will certainly aid relieve the pain and improve upper body posture.

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The continuous postural strain competent by the rhomboid muscles can make them dysuseful. This can limit the remarkable rotation of the scapula and also glenoid cavity, bring about bad shoulder mechanics. In turn, soft tconcerns in the shoulder area deserve to end up being injured and painful, especially throughout tasks that involve arm elevation over shoulder height. Such examples incorporate sporting tasks favor tennis and volleysphere.


References:

Palastanga, N., & Soames, R. (2012). Anatomy and also human movement: structure and also attribute (sixth ed.). Edinburgh: Churchill Livingrock.Standring, S. (2016). Gray"s Anatomy (41tst ed.). Edinburgh: Elsevier Churchill Livingrock.Netter, F. (2014). Atlas of Human Anatomy (sixth ed.). Philadelphia, PA: Saunders

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