Shoulder transverse adduction is a medial movement at the shoulder (glenohumeral) joint in a horizontal plane – moving the upper arm towards and across the chest with the back of the arm facing down – see Figure 1.
In anatomical terminology, a medial movement is one that moves part of the body closer to (medial to) the midline of the body.
The key muscles involved in this movement are the sternal and clavicular heads of the pectoralis major, and the coracobrachialis.
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