Body

muscle

Where it runs

From the back of the skull and the neck out to the outer end of the collarbone.

What it does

Lifts and helps rotate the shoulder blade upwards, so the arm can go overhead.

In a pull-up

Works when the arms are overhead. When it does all the work the shoulders creep up to the ears instead of settling down.

Drills that work it

In the programs

• Phase 1 — Set the shoulder blades — Shoulder: kipping works, strict pull-ups do not

Works alongside

Other structures the same drills work.

• Serratus anterior
• Lower trapezius
• Supraspinatus

General anatomy, simplified. It describes a structure, not anybody's shoulder, and cannot say what is wrong with yours.