Superficial muscles of the back are called groupsMuscular tissues that attach to the skeleton of the shoulder girdle. They are arranged in two layers. The upper layer constitutes a trapezius and latitudinal muscle, the lower one contains a large and small rhombic muscle.
The structure of the trapezius muscle
- upper (neck area);
- middle (upper part of the blades);
- the bottom (bottom of the scapula and the area below them).
Muscles have short tendon bundles.They form a rhombic pad only in the region of the upper thoracic and lower cervical vertebrae. Bunches of muscle radically converge to the scapula. Here they are attached to its axis, as well as to the acromial end of the clavicle and directly to the acromion itself. In the attachment area, between the point of attachment of the ascending bundles and the tip of the scapula, there is a small sized pouch box. It is located between the bone and the tendon itself. In the place where the trapezius muscle joins the acromion, there is an acromial subcutaneous bag. It is quite large. It is located on the back of the acromion.
Trapezius muscle: functions
- with simultaneous reduction of all parts of the muscle, in the condition of the fixed spine, the scapula is approaching it;
- with simultaneous reduction of the upper and lower fibers, the bone rotates along the sagittal axis;
- the scapula is lifted by the upper muscle bundles;
- The muscle, when contracted on both sides, helps to unbend the cervical region, this allows you to tilt your head back;
- with one-sided tightening, the front part of the head turns slightly in the opposite direction.