The trapezius muscle controls many movements of the shoulder and arm. You use it a lot when you throw, and it's also involved in moving your head and neck. The trapezius muscle is divided into three sections, which have different roles: Upper trapezius:Sometimes called the superior trapezius,...
The pecs are the main and the largest chest muscles. Their function is internally rotate the humerus (the upper arm bone) as well as adduct it (bringing it closer to the body). This last function is mainly responsible for the incline bench press motion. The pectoralis has two main heads,...
jaw, upper back and down the inside of the left arm; it can be triggered by exercise, stress, heavy meal or cold environment and relieved by rest or the oral drug called nitroglycerin.