What Is the Pectoralis Minor?

The pectoralis minor is located on the deep side of the pectoralis major muscle and is a triangular flat muscle. It starts from the fascia of 3 to 5 ribs and the surface of the intercostal muscles and ends at the coracoid process of the scapula. The pectoralis minor muscles pull the scapula forward and down. When the scapula is fixed, the pectoralis minor muscles can lift the ribs, but they only move when they inhale vigorously. The pectoralis minor muscles are innervated by the anterior medial thoracic nerve (neck 8, chest 1).

The pectoralis minor is located on the deep side of the pectoralis major muscle and is a triangular flat muscle. It starts from the fascia of 3 to 5 ribs and the surface of the intercostal muscles and ends at the coracoid process of the shoulder blades. The pectoralis minor muscles pull the scapula forward and down. When the scapula is fixed, the pectoralis minor muscles can lift the ribs, but they only move when they inhale vigorously. The pectoralis minor muscles are innervated by the anterior medial thoracic nerve (neck 8, chest 1).

Chinese name

Pectoralis minor

Foreign name

Pectoralis minor

Features

triangle

Location

Pectoralis major

Pectoralis minor auxiliary structure

1. Nerve: The pectoralis minor muscle generally starts from 3 to 5 ribs with 3 muscle teeth, and at the same time receives the dual innervation of the medial and lateral thoracic nerves. The intrathoracic and lateral nerves enter the muscles in the middle of the abdomen. After the muscles enter the muscle, the lateral thoracic nerves are divided into the upper and lower branches. The upper branch is distributed in the upper one muscle tooth and the lower branch enters the middle muscle tooth. Branches, the upper two branches line the middle muscle teeth (the largest one), and coincide with the lower branches of the lateral thoracic nerve. The medial thoracic nerve and lateral thoracic nerve emit a large number of secondary branches (4 to 5 branches) in the muscle, and the adjacent branches of the two neural trunks coincide with each other to form a "U" -shaped neural crest. Several branches were issued on the boll. A large number of pine needle-like thin branches are issued along the nerve branch, forming a nerve band (net) in the middle of the pectoralis minor muscle. From the nerve band, several slender nerve branches are sent to the beginning of the muscle, distributed in the corresponding muscle teeth, and a few nerve branches. To the end of the muscle. Nerve communication branches can be seen between the nerve trunks of the intrathoracic and lateral nerves and between the nerve branches of the following levels. From the nerve trunk and nerve branches, there are also small recurrent branches that are distributed in the apical tendon.

2. Pectoralis minor: It is a pinnate muscle with a pinnate angle of 11.5 °. The advantage of the feather muscle is that it can accommodate more muscle fibers in the same volume, which increases the physiological cross-sectional area, thereby enhancing muscle strength. At the same time, relying on changes in the plume angle, the amplitude of the whole muscle is increased to compensate for the shortness of the muscle fibers . Therefore, the distribution of muscle fibers increases the strength and amplitude of the pectoralis minor. In muscle transplantation, the muscle strength, speed, and amplitude of the selected donor muscle can only be matched with the in situ muscles to ensure the recovery of postoperative body functions. Therefore, the clinician must understand the characteristics of the in situ muscles and To understand the characteristics of the donor muscle, even the strength and speed of the entire muscle group need to be understood.

3. Blood vessels: The arteries of the pectoralis minor muscle are mostly branched from the thoracic acromion artery and are relatively constant. The venous distribution of the pectoralis minor muscles was quite variable, and no obvious accompanying pattern was seen.

Clinical techniques and application of pectoralis minor

After the position of the vascular nerve is determined, the position of the graft muscle and the trimming range can be determined. Fixing the first palm to the opposite palm position can create a larger space to accommodate the graft muscle. The lower and outer parts of the transplanted muscle are thicker than the upper and inner parts, which is consistent with the muscle thickness distribution characteristics of the original thumb to the palm muscle. One end of the graft muscle is sutured to the scaphoid nodule, most of the horns, the transverse carpal ligament, and the metacarpal aponeurotic stop, and the other end is sutured to the first metacarpal radial and dorsal periosteal membrane from the first metacarpal base to the metacarpophalangeal joint Radial sesamoid and dorsal aponeurosis to facilitate thumb extension after surgery.