Levator scapulae m.

Levator scapulae originates from the dorsal tubercles of the transverse processes of cervical vertebrae one to four. The muscle is inserted on the superior angle and adjacent medial border of the scapula.

The levator scapulae may lie deep to the sternocleidomastoideus at its origin, deep or adjacent to the splenius capitis at its origin and mid-portion, and deep to the trapezius in its lower portion.

When the spine is fixed, levator scapulae elevates the scapula and rotates its inferior angle medially. It often works in combination with other muscles like the rhomboids and pectoralis minor to rotate down.

Elevating or rotating one shoulder at a time would require muscles to stabilize the cervical spine and keep it immobile so it does not flex or rotate. Elevating both at once with equal amounts of pull on both side of cervical spinal origins would counteract these forces. Downward rotation would be prevented by co-contraction of other muscles that elevate the spine, the upper fibers of the trapezius, which is an upward rotator.

When the shoulder is fixed, levator scapula rotates and flexes the cervical spine laterally. When both shoulders are fixed, a simultaneous co-contraction of both levator scapulae muscles in equal amounts would not produce lateral flexion or rotation, and may produce straight flexion or extension of the cervical spine. Which would happen is unknown.