Pectoralis minor is a fan-shaped muscle in the front of the shoulder that secures the lateral angle of the scapula to the rib cage. Superficially, it is covered by the pectoralis major.
Origin – ribs 3-5. dissections show that it commonly attaches to the second rib and, occasionally attaches to the 6th rib.
Insertion – the medial aspect of the coracoid process of the scapula. This is usually a separate tendon from coracobrachialis and biceps femoris. Noted anomalies include a common tendon and an attachment to the greater tubercle of the humerus.
When the ribs are stabilized, pectoralis minor protracts and depresses the scapula. It stabilizes the pectoral girdle during downward movements like chopping wood or walking with a crutch. It synergizes with the pectoralis major, subclavius and latissimus dorsi in depressing the pectoral girdle.
When the pectoral girdle is stabilized, the pectoralis minor lifts the ribs for inhalation, especially during labored breathing. It synergizes with scalenes, serratus posterior superior and serratus anterior to lift the upper ribs and increase lung capacity.
The pectoralis minor and middle bellies of serratus anterior both connect the scapula with ribs 3-5. Both muscles have noted anomalies with attachments to ribs 2 and 6.
Pectoralis minor is invested in the costocoracoid membrane. This fascial structure forms a sheet that extends across the upper chest to also invest the subclavius. This membrane ties together the upper ribs, subclavius, pectoralis minor, clavicle, and coracoid process.
This membrane also covers the neurovascular bundle that feeds the upper extremity, making it an important part of Thoracic Outlet structures. you can read more about these structures in this post about Anatomy of Thoracic Outlet Syndrome.
This site is undergoing changes. Starting in early 2020, we began improving the format. We are also adding more extensive self-care, illustrations, therapist notes, anatomy, and protocols. We appreciate your input and feedback. You will see us adding posts and updating older posts as time permits.
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This post shows you how to press out the trigger points and stretch the infraspinatus muscle. It’s a small muscle on the back of the shoulder but creates a number of problems, including:
- shoulder pain when sleeping
- loss of grip strength
- upper neck pain
- pain along the inside edge of the shoulder blade
Tony Preston has a practice in Atlanta, Georgia where he sees clients. He has written and taught about anatomy, trigger points, and cranial therapies since the mid-90s.
*This site is undergoing major changes. We are reformatting and expanding the posts to make it easier to read. The result will also be more accessible and
will include more patterns with better self-care. In the meanwhile, there may be inconsistency in formatting, content presentation, and readability. Until we get older posts updated, please excuse our mess.