What is the primary muscle of the chest wall?

The primary muscle of the chest wall is the pectoralis major. This muscle plays a crucial role in movements of the shoulder joint, including flexion, adduction, and medial rotation of the arm. It is a large, fan-shaped muscle located on the anterior (front) side of the thorax, and it covers a significant portion of the chest, attaching to the sternum, clavicle, and the humerus.

The pectoralis major's position and function make it the most prominent muscle in the chest area, contributing both to the strength required for various upper body movements and the overall contour of the chest. It is also involved in stabilizing the shoulder joint during various activities. Its size and role distinguish it from other muscles associated with the chest and thoracic region, such as the intercostals and pectoralis minor, which have different functions and implications in respiratory mechanics and shoulder movements.