What is the difference between pectoralis major and minor

There is one muscle in particular that is responsible for our rounded shoulder issues. Pectoralis minor, a thin triangular muscle that inserts onto the coracoid process of the scapula, or shoulder blade. Since it connects on the top of the shoulder blade, when it engages it can pull the shoulder blade forward and down.

It also functions to draw the shoulders blades away from each other. Imagine hugging yourself. The pectoralis minor has some similarities to another troubling muscle, piriformis.

I refer to them both as nasty little muscles. They are each triangular in shape and whereas the piriformis connects the leg to the spine at the back of the body, the pectoralis minor connects the shoulder blade to the ribcage at the front of the body. The piriformis tends to shorten due to postural imbalances from the leg bones turning out while the pectoralis minor tends to shorten from the arm bones turning in.

The pectoralis minor lies underneath the pectoralis major, a thick, broad muscle that covers the upper chest. The pectoralis major flexes the humerus, the bone of the upper arm, picking up a baby , it draws the humerus away from the body bringing the arms up overhead in yoga , and across the body hugging yourself , in a somewhat similar way to the pectoralis minor.

These two muscles that overlap are supposed to glide over each other with distinction. Pectoralis minor moves from the back to the front of the body while pectoralis major moves from the outside to the inside in the front plane of the body. Unfortunately what often happens is that these muscles get glued together a rolfing term and begin to move as one unit. Distances between pectoralis major and pectoralis minor muscles were separated into 3 categories: less than 1 cm, between 1 and 3 cm, and greater than 3 cm.

No significant difference was observed in these percentages with regard to sex. Ten cadavers displayed asymmetry in pectoralis muscle origin distance. Eight specimens displayed shared fibers between pectoralis major and minor muscles. Conclusions: The anatomic relationship between the costal origin of the pectoralis major and minor muscles is highly variable.

Understanding this spatial relationship has important implications for cosmetic and reconstructive breast surgery.