Erector spine

The muscle, straightening the spine (m. Erector spinae) - the strongest of the autochthonous muscles of the back, extends all over the spine - from the sacrum to the base of the skull. It lies anterior to the trapezoidal, rhomboid, posterior jagged muscles, the widest mouse of the back. Behind the muscle, straightening the spine, is covered with a superficial leaf of the lumbosacral fascia. The muscle begins with thick tendon bundles on the dorsal surface of the sacrum, spinous processes, supraspinous lumbar ligaments, XII and XI thoracic vertebrae, posterior segment of the iliac crest and lumbosacral fascia. Part of the tendon bundles, starting in the sacrum, merges with the bundles of the sacro-tubercular and dorsal sacroiliac ligaments.

At the level of the upper lumbar vertebrae, the straightening muscle of the spine is divided into three tracts: lateral, intermediate and medial. Each path gets its name. The lateral tract is the ilio-rib muscle, the intermediate tract is the longest muscle, the medial tract is the spinous muscle. Each of these muscles in turn is divided into parts.

Features of the structure of the muscle, straightening the spine, formed during anthropogenesis in connection with the upright. The fact that the muscle is developed strongly and has a common origin on the pelvic bones, and above divides into separate tracts that attach widely to the vertebrae, the ribs and the base of the skull, can be explained by the fact that it performs the most important function - keeping the body in a vertical position. At the same time, the division of the muscle into separate tracts, the division of the muscles at different levels of the dorsal side of the trunk into shorter muscles, having a smaller length between the points of origin and attachment, allows the muscle to act selectively. So, for example, with the reduction of the ilio-rib muscle of the waist, the corresponding ribs are pulled downwards, thereby creating a support for the manifestation of the action force of the diaphragm when it is contracted, etc.

The function of the entire muscle, straightening the spine, accurately reflects its name. Since the parts of the muscle have a beginning on the vertebrae, it can act as a mass as the extensor of the spine (trunk) and head, overcoming the resistance of the ventral muscles and the gravity of the body. Cutting in separate parts on both sides, this muscle can lower the ribs, unbend the different parts of the spine, tilt back the head. When unilateral reduction tilts the spine (trunk) in the same direction. The muscle develops a great strength when it prevents the body from falling forward under the action of ventral muscles, which have a greater lever of action on the spinal column.