origin: lateral half of the first six divisions
of the body of the sternum and
sometimes the xiphoid process
insertion: ventral border of the bicipital groove
at the proximal end of humerus
nerve: anterior thoracic
action: adducts arm
origin: anterior surface of ribs 3, 4, and 5
near the costal cartilages
insertion: coracoid process of scapula
nerve: medial pectoral (C8, T1)
action: depress, protract, and inferior
rotation of scapula
Pectoralis minor is one of the five muscles that are grouped as muscles of the scapula, or sometimes as muscles that moor the scapula. In humans it is one of two pectoral muscles and it is smaller than pectoralis major but in the cat it is the largest of the four pectoral muscles. The above drawing of the origin and insertion might help visualize this information (red is the origin, blue the insertion).
2009 by William C. Johnson II
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