The muscles of the chest are an important component of the musculoskeletal system. They begin on the front surface of the chest, then go to the belt of the upper limbs. In addition, autochthonous (own) muscles are secreted, which are fixed to the ribs. According to their anatomical location, they carry out the movement of the upper limbs, and also participate in the process of inspiration.
According to the classification, the muscles that belong to the upper limbs and the own muscles of the chest are isolated. This division corresponds to the functions performed, and not to the anatomical features.
The first group includes the large, jagged and small pectoral muscle. The first starts from the anterior surface of the clavicle (its medial side), the cartilage of the second to seventh ribs and ends in the anterior tendon of the rectus abdominis muscle. Above, the muscle attaches to the large tubercle of the humerus. It performs the following functions: bringing the upper limbs to the body, turning them inward, the part of the fibers that adjoins the clavicle participates in bending the arm. She also participates in the process of inspiration. For this, the upper limbs should be brought to the body, fixed. She also participates in brachiation (pull-ups).
The pectoralis minor muscle is located under the pectoralis major. It originates from the second and continues to the fifth rib, attached to the process of the scapula. The muscle performs the following functions: when contracting, it pulls the scapula in the front and lower directions. When fixing the hands, she is involved in the breathing process.
The subclavian pectoral muscle is located between the clavicle and the first ribs. It performs the following functions: fixation of the sternoclavicular joint, pulling the clavicles medially and down.
The anterior dentate muscle is projected onto the lateral region of the chest. It comes from the nine upper ribs, then attaches to the inner edge of the scapula. Together with it, a rhomboid muscle is attached to this edge , which determines the similarity of their functions. These include fixation of the scapula, rotation of the lower part of this bone laterally and in front, which is observed when the arm is raised above the horizontal line.
The external and internal intercostal pectoralis muscle belong to the own muscles of this area. They are fixed to the costal cartilage. The difference between the external and internal muscles is in the course of their fibers. The former are characterized by a direction from back to front and from top to bottom. Internal intercostal muscles have the opposite course of their fibers, which reach the sternum. However, they perform the same functions.
The costal muscles also belong to the group of own muscles. They are located on the inside of the chest in its lower part. The hypochondria are attached to the corners of the ribs. A feature of the course of their fibers is to throw over two ribs.
The lower pectoral muscle (transverse) is located on the inner surface and also belongs to the group of its own muscles. It has a vertical stroke of fibers. This distinguishes her from all the formations of his group.
All of the chest’s own muscles are involved in the breathing process. This is their main function. The muscles lift all the ribs, and the rib cage expands in all directions. The result is a breath. The exhalation occurs passively, this is facilitated by the elasticity of the chest and lungs. There is a theory according to which the internal intercostal muscles are taken in the implementation of a quiet exhalation. However, of all formations of this type, the diaphragm makes the largest contribution to the act of breathing.
Any pectoral muscle is a vital formation, since, in addition to motor functions, it performs a respiratory function.