The teres major muscle
The teres major muscle is a small muscle that contributes to stabilizing the shoulder joint. It’s close relationship with the rotator cuff muscles means that it probably helps them out. It also has a strong relationship with the latissimus dorsi muscle and assists it with internal rotation of the shoulder joint.
What does teres major mean?
Teres means rounded. Major refers to the fact that it is the larger of the two “teres” muscles. Teres major works hand in hand with latissimus dorsi. It’s often called the “lat’s little helper”.
Where does the teres major attach?
Teres major is a superficial muscle located below teres minor.
Origin of teres major
Teres major originates on the upper surface of the inferior (lower) angle of the scapula (shoulder blade).
Insertion of teres major
It inserts on the medial (inner) lip of the bicipital groove. The bicipital groove is the groove at the top of the humerus that the biceps tendon passes through.
What actions does the teres major do?
Teres major is responsible for:
- Medial rotation of the humerus
- Adduction of the humerus
- Extension of the humerus
Postures where the teres major muscle contracts
Teres major isn’t often responsible for moving us into postures. It’s used for stabilizing the shoulder joint. This is especially true when we are supporting our body weight with our hands or forearms as you see below.