Levator scapulae:

A strap-like muscle which appears in the floor of the posterior triangle, it arises from the posterior tubercles (i.e. from true transverse processes) of the upper four cervical vertebrae by slender slips of tendon. The four slips fuse into the long belly, which usually is longitudinally split. It courses downwards to be inserted into the upper angle of the scapula. It may not be derived from the upper limb myotomes, but from the external of the three layers of the body wall.

Nerve supply of levator scapulae:

From the cervical plexus (C3 and 4, anterior rami), reinforced by the dorsal scapular nerve (nerve to the rhomboids) (C5).

Action of levator scapulae:

Similar to the rhomboid muscles.