Arm internal rotation
Internal or medial rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is internally rotated around the longitudinal plane of the humerus such that the hand moves towards the midline of the body.
The degree of rotation is dependent on the degree of abduction at the shoulder. In adduction internal rotation can be up to 70°. As the arm is abducted this increases towards 95°. It is the opposite of arm external rotation.
It is produced by:
- subscapularis
- latissimus dorsi
- teres major
- deltoid (anterior fibers)
See also movements of the arm.