Diagram Pectoralis Major. It is large and fan shaped and is composed of a sternal head and a clavicular head. The pectoralis major is the most superficial muscle in the pectoral region.
The dominant muscle in the upper chest is the pectoralis major. Pectoralis major is innervated by the lateral and medial pectoral nerves two branches of the brachial plexus. Major larger is a large fan shaped chest muscle.
It functions to pull the arm towards the chest.
Shoulder horizontal flexion moving the arms forwards in front of the body upwards phase of a press up. Pectoralis minor deep to pectoralis major is the pectoralis minor. The pectoralis major is located superficially on the. The distal attachment of both heads is into the intertubercular sulcus of the humerus.