The big neck muscle

What it does

The sternocleidomastoid runs from the breastbone and collarbone up and back to the bony bump behind your ear. One side turns your head to the opposite side and tilts it towards the same shoulder; both together bend your head forward.

Why it matters

It is a key landmark in the neck. The pulse in your neck is felt just in front of it, and babies with a tight one on one side tilt their head, a condition called torticollis.

Nearby

• The traps
• The accessory nerve
• The collarbone
• The breastbone
• The carotid arteries

Read more

• Sternocleidomastoid — Wikipedia