Pectoralis minor muscle

The pectoralis minor muscle is a muscle in the chest that connects several ribs at the front of the chest to the scapula (shoulder blade). The pectoralis minor is located underneath the pectoralis major muscle.

Action
The pectoralis minor assists other muscles, notably the serratus anterior muscle, in protracting the scapula by pulling downward on the coracoid process. If the scapula is being held in place by other muscles, then it elevates the ribs it originates at.

Origin
The pectoralis minor originates from the third, fourth, and fifth ribs at the front of the chest. Some individuals vary in this location, having a pectoralis minor that originates instead from the second, third, and fourth ribs.

Insertion
The pectoralis minor inserts at the medial and upper surfaces of the coracoid process - the part of the scapula that protrudes forward under the clavicle near the shoulder joint.

Innervation
The pectoralis minor is innervated by the medial pectoral nerve.

Word origin
The word pectoralis minor comes from pectoralis, Latin for of the chest or of the breast. The minor part of the word differentiates it from the pectoralis major muscle, which it sits under.