The biomechanics of the human body is possible only due to the unique anatomical structure, both of the whole body as a whole, and of individual systems in particular. The muscle apparatus in the process of movement plays a leading role. For example, back muscles. The anatomy of the spinal muscles is very complex and requires detailed study by future general surgeons, neurosurgeons, traumatologists and urologists. It is these specialists who most often have to face a similar question.
So, what are the features of the back muscles? The anatomy of the musculature of the trunk is characterized by large muscle masses. The muscle fibers on the back are larger compared to the head or neck, as they feel a greater load when moving and occupy a vast area on the human body. The neck muscles, the anatomy of which is extremely difficult due to the large number of nerve plexuses and vital vascular bundles located in this area, smoothly pass into the muscles of the back and chest. The back muscles are divided into two main groups, which differ from each other in the direction of the muscle fibers - superficial and deep.
It is believed that the first back muscles, the anatomy of which is phylogenetically more associated with the structure of the muscles of the limbs, are muscles that have moved from the upper shoulder girdle during development. Deep spinal muscles, as is commonly believed, develop from intrauterine muscle bookmarks, or myotomes, in this area. They retained a partial segmental structure. The principle of distribution of deep muscles is the formation of several muscle layers by these structures. At the same time, the deeper the muscle is located, the shorter it will look.
The following types of muscles belong to the superficial spinal muscles:
- a trapezius muscle , or musculus trapezius, which begins from the bony skeleton of the spinous processes of the entire series of thoracic vertebrae. Its function is the movement of the shoulder blades and extension of the head.
- the latissimus dorsi , occupying its entire lower region. M. latissimus dorsi, as a rule, begins from the lower 5 thoracic vertebrae, as well as all lumbar and sacral vertebral spinous processes, four pairs of lower ribs and both iliac crests. Function: lowering the raised arm and rotating the shoulder inward.
- rhomboid muscle . It lies immediately below the trapezoid. Function m. rhomboideus is also associated with scapular movement.
- muscle lifting the scapula . This muscle arises from the processes of the cervical vertebrae, ending on the shoulder blade in its upper corner. M. levator scapulae, answering its name, carries out the rise of the scapula.
- back and lower dentate muscles . These are antagonist muscles. If the first of them (meaning m. Serratus posterior superior) raises the ribs, then the last (m. Serratus anterior inferior), on the contrary, lowers them.
Speaking of deep back muscles, it should be noted that they consist of separate groups of long and short muscles that are located along the entire long spinal column. This is from the occipital bone of the head to the sacral region. The deep spinal muscles include:
- muscle straightening the torso . It is located in the sacrum and crests of both ilium, from where it originates, goes straight up and ends at the occipital bone. Its function is associated with the straightening and bending of the torso, as well as its lateral inclinations. M. erector trunci has three portions, on the reduction of which the nature of the movements will depend.
- transverse spinous muscle , or m. transversospinalis is a complex consisting of small and short muscle fibers. These back muscles, the anatomy of which at first glance seems chaotic, go in an oblique direction from the processes of the vertebrae and help in the extension of the back and trunk.
- a muscle belt . She carries out head rotations and extension of the cervical spine.
The lumbar muscles, in fact, do not belong to the actual spinal muscles. Anatomically, they relate to the muscles of the pelvic girdle.