The subscapularis is a muscle in your shoulder that helps you internally rotate your arm. When your arm is internally rotated, it means that your palm is facing back, behind your body. The subscapularis is the largest muscle in the rotator cuff, which is a group of muscles that attaches your upper arm to your shoulder.

Where is the subscapular region?

The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.

What is the job of the subscapularis?

Primary function is internal rotation of the humerus. It helps in shoulder adduction and extension in certain positions.