Rhomboid Major Muscle
Teres Major Muscle – Attachments, Action & Innervation
Teres major is a thick and ovoid muscle in the upper arm.
Despite their similar names, teres major has different actions and innervation from the teres minor.
The teres major muscle is mainly responsible for the medial rotation of the arm and it also contributes to static posture and arm-swinging.
Teres Major Muscle
Attachments of Teres Major Muscle Origin & Insertion
Origin: (proximal attachments)
Lower lateral border and inferior angle of the scapula.
Insertion: (distal attachments)
Medial lip of the intertubercular (bicipital) groove of the anterior humerus.
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Actions of Teres Major:
b. Medially rotates the arm at the shoulder (glenohumeral) joint.
c. Extends the arm at the shoulder (glenohumeral) joint.