Subscapularis
Subscapularis
Pronunciation: sub-scap-you-LAIR-iss
For beginners
The rotator cuff muscle that turns the arm inward. It sits between the shoulder blade and the ribs, so you cannot feel it from the surface.
Show the advanced explanation
The only rotator cuff muscle on the anterior scapula, it is the primary internal rotator among the cuff and provides important anterior stability to the glenohumeral joint.
Structure & function
- Location
- A deep muscle on the front (rib-cage side) of the shoulder blade.
- Origin
- Subscapular fossa (anterior surface of the scapula).
- Insertion
- Lesser tubercle of the humerus.
- Main action(s)
- Internally (medially) rotates the arm and stabilizes the humeral head.
- Joint(s) crossed
- Glenohumeral joint
- Movement plane
- transverse
- Innervation
- Upper and lower subscapular nerves (C5–C6)
- In daily movement
- Rotates the arm inward — like reaching across your body.
- In exercise
- Stabilizer during pressing; internal-rotation mover.
- Commonly confused with
- Its internal-rotation role overlaps with pectoralis major and latissimus dorsi.
- Common misconceptions
- Not all rotator cuff muscles rotate outward — the subscapularis rotates inward.
Exercises that use this muscle
As a secondary / stabilizer
- Dumbbell Overhead Press (stabilizer)
- Push-Up (stabilizer)
- Barbell Bench Press (stabilizer)
⚠ Safety note
Balance internal- and external-rotation training to support shoulder health.
Sources
“The subscapularis is a rotator cuff muscle that medially (internally) rotates the arm.”
Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.5 Muscles of the Pectoral Girdle and Upper Limbs
Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19
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