Levator Scapulae Anatomy
Levator Scapulae muscle is a strap-like, slender muscle that is seen in the floor of the posterior triangle. This muscle originates from the transverse processes of the atlas and axis and also from the posterior tubercles of the third and fourth cervical vertebrae by slender slips of tendon. The insertion of levator scapulae is into the medial border of the scapula from the superior angle to the spine. The superior third of this slender levator scapulae lies deep to the sternocleidomastoid muscle while the inferior third lies deep to the trapezius. The name of levator scapulae describes its action and function of elevating the scapula together with the descending part of the trapezius. Levator scapulae also helps to fix the scapula by resisting the forces that would depress it such as when carrying a load.
The four slips of muscle fuse into the long belly that is usually longitudinally split and then courses downwards to be inserted into the upper angle of the scapula. In the embryology of this muscle, it may not be derived from the upper limb myotomes, but from the external of the three layers of the body wall.
Levator Scapulae Nerve Supply
Levator scapulae is innervated by the cervical plexus through C3 and C4 cervical segments of the spinal cord via the anterior rami. The innervation of this muscle is also reinforced by the dorsal scapular nerve (which is the nerve to the rhomboids, C5).
Levator Scapulae Blood Supply
The blood supply to Levator Scapulae is through branches of Transverse cervical artery and ascending cervical artery.
Levator Scapulae Origin and Insertion
The origin of the levator scapulae muscle is from the posterior tubercles of transverse processes of C1 to C4 vertebrae while the point of insertion is at the medial border of the scapula superior to root of spine.
Levator Scapulae Functions and Actions
Levator scapulae muscle helps to elevate the scapula together with the upper part of trapezius muscle. Levator scapulae also laterally flexes the neck to the side of the active muscle when only the muscle of one side is acting, but when acting bilaterally (both the left and right levator scapulae are acting), it causes extension of the neck with the trapezius. Another function of this muscle tilting the glenoid cavity inferiorly by rotating the scapula, it does this action together with the rhomboids and pectoralis minor.