The pectoralis minor is a piece of soft tissue in a relatively deep location, hidden beneath the pectoralis major, and many physicians do not pay attention to its clinical significance; it is a special soft tissue, and its contracture can compress both blood vessels and nerves. Its own fascial points can also produce corresponding symptoms. Today, we will introduce this soft tissue that is often overlooked by physicians. The pectoralis minor muscle begins medially at the tip of the rostral process; it attaches downward to the 3rd, 4th, and 5th ribs. But its fascia is very extensive, almost the same as the fascia of the pectoralis major. The pectoralis minor causes the most intense pain in the anterior triangle, which can extend to the subclavian area and extend along the upper arm, elbow, forearm, and ulnar side of the palm, finally reaching the three fingers on the ulnar side. It also causes pain in the anterior thoracic region, similar to the pectoralis major, and can form a neurovascular bundle jam in the upper limb, forming a thoracic outlet syndrome. 1, there is axillary artery passing under the pectoralis minor muscle, when the pectoralis minor muscle becomes short, it can form the sign of no pulse in the raised hand; 2, there are multiple bundles of nerves passing under the pectoralis minor muscle, if the pectoralis minor muscle becomes short it can cause jamming on the nerves, this condition mostly produces fascial points together with the oblique angle muscle. Causes of pain: poor sitting posture, such as prolonged shoulder gathering and frustration. Long-term tightening of the schoolbag strap and weakness of the lower trapezius muscle can lead to shortening of the pectoralis minor muscle, so the muscle strength of the lower trapezius muscle should be strengthened and the fascial points of the lower trapezius muscle should be eliminated when treating the pectoralis minor muscle.