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