Muscle
Subscapularis
Anterior cuff muscle for inward rotation
High-yield
Its main insertion is on the lesser tubercle. The other three cuff muscles attach chiefly to the greater tubercle.
Overview
Subscapularis covers the rib-facing surface of the scapula and reaches the front of the humerus. Its tendon forms the anterior part of the rotator cuff, supporting the joint as the arm rotates inward.
Learning this group? Read The rotator cuff muscles, explained.
Reference facts
- Origin
- Subscapular fossa on the costal surface of the scapula
- Insertion
- Lesser tubercle of the humerus
- Action
- Internally rotates the arm, assists adduction and supports shoulder stability
- Innervation
- Upper and lower subscapular nerves, chiefly C5–C6 with possible C7 contribution
- Blood supply
- Principally branches of the subscapular artery
Clinical correlation
Subscapularis injury can cause painful or weak internal rotation. Clinicians use findings such as the lift-off and belly-press tests together with the rest of the shoulder assessment; one maneuver cannot identify every tear.
Frequently asked questions
What does the subscapularis do?
The subscapularis internally rotates the arm, assists adduction and supports shoulder stability.
What nerve innervates the subscapularis?
The subscapularis is innervated by the upper and lower subscapular nerves, chiefly C5–C6 with possible C7 contribution.
Where does the subscapularis attach?
The subscapularis originates from the subscapular fossa on the costal surface of the scapula and inserts on the lesser tubercle of the humerus.
What is the blood supply of the subscapularis?
The subscapularis is supplied by the principally branches of the subscapular artery.