STERNOCLEIDOMASTOID
| ORIGIN Anterior and superior manubrium and superior medial third of clavicle |
 |
| INSERTION Lateral aspect of mastoid process and anterior half of superior nuchal line |
|
| ACTION Flexes and laterally rotates cervical spine. Protracts head when acting together . Extends neck when neck already partially extended |
|
| NERVE Spinal accessory nerve (lateral roots C1-5) |