Extrinsic Chest Muscles

Extrinsic Chest Muscles – Functional Anatomy

 Extrinsic chest muscles, as you can see, originate on the front of the axial skeleton and insert on the upper extremity. Generally speaking, they protract the scapula and draw the humerus toward the midline. This gets a little more complicated with the pectoralis major as the clavicular head as it allows us to flex the …

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Pectoralis Minor – Functional Anatomy

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 …

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Pectoralis Major – Functional Anatomy

Dissection studies show that the pectoralis major varies dramatically. There are commonly 2-5 laminates, sometimes 6 or 7, and sometimes the entire pectoralis is missing (Poland Syndrome). Also, the overlap of sections varies among studies. The variation illustrated here is common and I used it because, well, it was fun to illustrate and shows how differently …

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