Arm in different position of elevation, side view


Lifting the arm up to 90 degree produces a cradle below the arm consisting of the pectoralis in the front, the teres mayor and latissimus dorsi in the back and the serratus anterior as part of the wall of the thorax.

Lifting the arm further and turning it towards the head shift latissimus dorsi and teres mayor beside the head of the humerus and towards the pectoralis, thus transforming the cradle into a rather protruding body part.