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Pectoralis minor

Other Terms: Pectoralis minor muscle, Musculus pectoralis minor, Muscle petit pectoral

Muscle parts

None

Latin name

Musculus pectoralis minor

Latin muscle parts

None

Group

Pectoral girdle muscle or Thoracic wall – lateral musculature – supracostal or outermost layer

Etymology

In English, this muscle’s name is the lesser 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 minor comes from the Greek meion meaning “lesser.” As is typical in anatomical terminology, this comparative reference clues you into the fact that this is a smaller version of a similar placed larger muscle.

Origin

Junctions of ribs 3, 4, and 5 with their costal cartilages and to the fascia of the external intercostal muscles.

Insertion

Medial border of the coracoid process of the scapula.

Action

Abduction (protraction) of the scapula – the pectoralis minor works with the serratus anterior in protracting the scapula. Downward rotation of the glenoid cavity – though it is a thin sheet of muscle, it has a strong mechanical advantage and works with the rhomboideus major muscle in rotating the glenoid cavity of the scapula downward. Elevates the ribs – it is inactive during normal quiet breathing but becomes active during forced inspiration to help expand the volume of the rib cage.

Nerve supply

Medial and lateral pectoral nerves (C6, C7, and C8)

Blood supply

Thoracoacromial artery via the pectoral and deltoid branches, superior thoracic artery, lateral thoracic artery, and from perforating branches from the anterior intercostal arteries.

Latin

Musculus pectoralis minor

French

Muscle petit pectoral

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