Corpus: Levator scapulae muscle
from Latin: levare - to lift, to lighten; scapula - shoulder blade
Synonym: scapula levator
1. Definition
The levator scapulae muscle is part of the middle layer of the secondary back muscles.
2. Anatomy
The levator scapulae muscle originates from the transverse processes of the 1st and 2nd cervical vertebrae, as well as from the posterior tubercles of the transverse processes of the 3rd and 4th cervical vertebrae. The muscle fibers descend steeply in a lateral and downward direction toward the scapula, where they insert at the medial angle and along the medial border of the scapula above the spine of the scapula. The accessory nerve (cranial nerve XI) runs along the lateral edge of the muscle.
3. Innervation
The levator scapulae muscle is innervated by the dorsal scapular nerve, a branch of the brachial plexus (specifically from the supraclavicular part). It also receives innervation from fibers of the 3rd to 5th cervical nerves via the cervical plexus.
4. Function
When the levator scapulae muscle contracts, it elevates the scapula in a craniomedial direction. In conjunction with other muscles, it also rotates the lower end of the scapula medially, contributing to the retraction of the elevated arm. If the scapula is fixed, contraction of the levator scapulae muscle tilts and rotates the neck to the same (ipsilateral) side.