Pectoralis major muscle

The pectoralis major (from Latin pectus, meaning 'breast') is a thick, fan-shaped muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, a thin, triangular muscle. The pectoralis major's primary functions are flexion, adduction, and internal rotation of the humerus. The pectoral major may colloquially be referred to as 'pecs', 'pectoral muscle' or 'chest muscle' due to it being the largest and most superficial muscle in the chest area.Pectoralis major highlighted on the trunk – frontal viewAnterior surface of sternum and costal cartilages, showing originsLeft clavicle. Superior surface, showing origins.Left clavicle. Inferior surface, showing origins.Left humerus. Anterior view, showing insertion.The axillary artery and its branchesThe brachial arteryThe right brachial plexus with its short branches, viewed from in frontThe right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in frontNerves of the left upper extremityThe left side of the thoraxSurface anatomy of the front of the thorax and abdomenPectoralis major muscleAn individual with an abdominal portion of the pectoralis major, and an accessory sternalis muscle. Both these are anatomical variations. The pectoralis major (from Latin pectus, meaning 'breast') is a thick, fan-shaped muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, a thin, triangular muscle. The pectoralis major's primary functions are flexion, adduction, and internal rotation of the humerus. The pectoral major may colloquially be referred to as 'pecs', 'pectoral muscle' or 'chest muscle' due to it being the largest and most superficial muscle in the chest area. It arises from the anterior surface of the sternal half of the clavicle; from breadth of the half of the anterior surface of the sternum, as low down as the attachment of the cartilage of the sixth or seventh rib; from the cartilages of all the true ribs, with the exception, frequently, of the first or seventh, and from the aponeurosis of the abdominal external oblique muscle.