Sternocleidomastoid
Sternocleidomastoid can clearly be seen when you turn your head to one side, on the opposite side of the neck.
Origin
- Anterior surface of the upper sternum Inner part of the clavicle.
Insertion
- Mastoid process (behind the ear).
Actions
- Contraction on both sides: Flexes the neck.
- Contraction on one side only: Laterally flexes (side bends) to the same side and rotates to the other side.
Innervation
- Acessory XI nerve.
Daily uses
- Looking at the floor.
- Looking over your shoulder.
- Holding the phone between your ear and shoulder.
Example stretches
- Neck rotation stretch.
Related injuries
- Postural kyphosis.
- Tight muscles in the upper back and neck.
Related muscles
- Levator scapulae.
