Teres major works closely with latissimus dorsi in adducting and extending the humerus. The lateral portion of latissimus dorsi usually twists around teres major and lives in the same fascial sheath. Latissimus, in a minority of times, also attaches to the inferior scapula.
Origin – the posterior, inferior edge of the lateral border of the scapula
Insertion – medial lip of the bicipital groove of the humerus
Function – adducts and medial rotates the humerus when it is lateral to the body, extends the humerus when it is in horizontal flexion (in front of the body)
Tony Preston has a practice in Atlanta, Georgia where he sees clients.
He has written and taught about anatomy, trigger points and cranial therapies since the mid-90s.