How to Identify the Pectoralis Minor

The pectoralis minor is underneath the pectoralis major in the upper part of the chest and covered by the clavipectoral fascia. It is a thin, triangular muscle that is usually penetrated by branches of the medial pectoral nerve on their way to the pectoralis major. The following steps will help you identify the pectoralis minor muscle.

Instructions

1. Read up on Latin roots to know that "pectoralis" means "chest" and "minor" means "small." This is the smaller of the two chest muscles.

2. Examine the pectoralis minor to see that it depresses and downwardly rotates the scapula, helps in scapular protraction from a retracted position and steadies the scapula. The pectoralis minor is trained with the same exercises used for the pectoralis major.

3. Observe how the pectoralis minor originates from the outer surface of the second to sixth ribs near the cartilage, although this is highly variable. It is also attached to the aponeuroses that cover the intercostalis.

4. Look at how the fibers of the pectoralis minor pass up and laterally to form a flat tendon that inserts into the medial aspect of the coracoid process of the scapula. This tendon occasionally extends to the greater tubercle.

5. Research the nervous system to know that the nerve for the pectoralis minor is the medial pectoral nerve from the eighth cervical and first thoracic nerves.

6. Study the circulatory system to know that the blood supply for the pectoralis minor is the lateral thoracic artery.

Resources

• Read a medical glossary.