pectoris

Pectoris is a term of Latin origin meaning the chest. In medical usage, pectoris appears in genitive form in phrases such as angina pectoris, literally “pain of the chest,” to describe chest-related conditions, particularly those involving the heart. In anatomy, the related adjective pectoralis is used in the names of chest muscles and region, such as the pectoral region of the anterior chest wall.

The pectoral region houses several muscles important for upper limb movement. The pectoralis major is a thick, fan-shaped muscle on the anterior chest wall. It has two heads: the clavicular head originates from the medial half of the clavicle, and the sternocostal head from the sternum and upper costal cartilages. It inserts on the lateral lip of the intertubercular groove of the humerus. Its actions include flexing, adducting, and medially rotating the arm, and it is mainly innervated by the lateral and medial pectoral nerves.

The pectoralis minor lies beneath the major, originating from ribs 3–5 and inserting on the coracoid process of the scapula. It serves to stabilize and protract the scapula, drawing it anteriorly and inferiorly against the thoracic wall, and it can assist in deep inspiration. Its nerve supply comes from the medial pectoral nerve, with some contribution from communications with the lateral pectoral nerve.

Clinically, angina pectoris is the best-known use of the term, describing chest pain due to myocardial ischemia, typically triggered by exertion and relieved by rest or nitroglycerin.