Sternocleidomastoid

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

How can I stretch it?

• Neck rotation stretch