Levator scapulae muscle
Levator scapulae is a long and slender muscle that anatomically belongs to the superficial layer of extrinsic muscles of the back. Functionally, however, it is considered to be a muscle of scapular motion along with the rhomboids, serratus anterior, serratus posterior superior and inferior muscles. The levator scapulae muscle extends from the transverse processes of vertebrae C1-C4 to the medial border of scapula.
As its name suggests, the main function of this muscle is to elevate the scapula. Additionally, levator scapulae acts with the trapezius, latissimus dorsi, rhomboids, pectoralis major and pectoralis minor muscles to inferiorly rotate the glenoid cavity, stabilize the spine, and extend and laterally flex the neck.
In this article, we will discuss the anatomy and function of the levator scapulae muscle.
|Origin||Transverse processes of vertebrae C1-C4|
|Insertion||Medial border of scapula (from superior angle to root of spine of scapula)|
Scapulothoracic joint: Draws scapula superomedially, rotates glenoid cavity inferiorly;
Cervical joints: Lateral flexion of neck (ipsilateral), extension of the neck
|Innervation||Anterior rami of the nerves C3 and C4, dorsal scapular nerve (branch of the C5)|
|Blood supply||Transverse cervical and ascending cervical arteries (branches of the thyrocervical trunk)|
Origin and insertion
Levator scapulae originates from the transverse processes of the first four cervical vertebrae. The muscle fibers descend laterally to insert at the superior angle and medial border of scapula, between the superior angle and base of the spine of scapula.
Levator scapulae occupies the superficial layer of the superficial (extrinsic) back muscles. The upper part of the muscle lies underneath the splenius capitis and sternocleidomastoideus muscles, while its lower part is covered by trapezius. Only the middle part of the levator scapulae remains uncovered. For that reason, the muscle can be most easily palpated in this area. In addition, the middle part helps to form the floor of the posterior triangle of the neck.
Learn the anatomy of the levator scapulae muscle with our handy trunk wall muscle anatomy chart. You'll find tables clearly showing you the attachments, innervations and functions of every muscle in this region.
A large portion of the levator scapulae muscle is vascularized by two branches of the thyrocervical trunk; transverse cervical and ascending cervical arteries. Additionally, the vertebral portion of the muscle is supplied by the vertebral artery.
The main function of the levator scapulae muscle is to elevate and retract the shoulder girdle at the scapulothoracic joint. At the same time, it helps in preventing the depression of the girdle when carrying heavy loads. Additionally, the muscle participates in the stabilization of the scapula and the inferior rotation of the glenoid cavity.
When acting on the cervical joints, unilateral contraction of the muscle produces ipsilateral flexion of the neck, while bilateral contraction contributes to extension of the neck. The actions of levator scapulae are facilitated by actions of the trapezius, latissimus dorsi, rhomboids, pectoralis major and minor muscles.
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An isolated lesion of the dorsal scapular nerve with a consequent paralysis of the levator scapulae muscle is very rare. The symptoms include “winging” of the scapula (scapula alata), as well as atrophy of both the levator scapulae and rhomboid muscles. As the affected patients may have no clear complaints, the correct diagnosis is often made too late.
Levator scapulae is one muscle of the human body which is prone to stiffening and chronic pain due to false posture in everyday life. Common causes include carrying heavy shoulder bags, permanent lifting of the shoulders while sitting at a desk and sleeping on one side of the body without proper head support.