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Pars clavicularis
Other Terms:
Pars clavicularis (Musculus pectoralis major),
Clavicular head of pectoralis major,
Pars clavicularis musculus pectoralis majoris
Muscle parts
Clavicular head; Sternocostal head; Abdominal part
Latin name
Musculus pectoralis major
Latin muscle parts
Pars clavicularis; Pars sternocostalis; Pars abdominalis
Group
Shoulder joint muscle – intertubercular groove group
Etymology
In English, this muscle’s name is the greater muscle of the breast. The term pectoral is derived from the Latin word pectus meaning “breast.” This is an ancient term that was initially applied to ornamental breastplates and armor worn by priests and warriors. The term major comes from the Latin maior meaning “greater.” As is typical in anatomical terminology, this comparative reference clues you into the fact that this is a larger version of a similar placed smaller muscle.
Origin
Sternal half of clavicle, anterior surface of sternum and costal cartilages 1 to 7.
Insertion
Lateral ridge of the intertubercular groove of the humerus
Action
Adduction of the humerus – both the clavicular and sternocostal heads of the pectoralis major are active during this movement of the humerus, both with and without resistance. Medial rotation and flexion of the humerus – the clavicular head of the pectoralis is the portion of the muscle active during these movements. In addition to these limb movements, the pectoralis major is active in forced inspiration.
Nerve supply
Medial and lateral pectoral nerves (C5, C6, C7, C8, and T1)
Blood supply
Thoracoacromial artery via the deltoid and pectoral branches; superior thoracic artery; perforating branches from the internal thoracic artery and anterior intercostal arteries; minor contributions can arise from the lateral thoracic and thoracodorsal arteries.
Latin
Pars clavicularis musculus pectoralis majoris
