|
The erector spinæ ( )〔 Lat. "that which straightens out the spines"〕 is a muscle group of the back in humans and other animals, which extends the vertebral column (bending the spine such that the head moves posteriorly while the chest protrudes anteriorly). It is also known as sacrospinalis in older texts. A more modern term is extensor spinae,〔Terminologia Anatomica, 1999.〕 though this is not in widespread use. ==Structure== The erector spinæ is not just one muscle, but a bundle of muscles and tendons. It is paired and runs more or less vertically. It extends throughout the lumbar, thoracic and cervical regions, and lies in the groove to the side of the vertebral column. Erector spinæ is covered in the lumbar and thoracic regions by the thoracolumbar fascia, and in the cervical region by the nuchal ligament. This large muscular and tendinous mass varies in size and structure at different parts of the vertebral column. In the sacral region, it is narrow and pointed, and at its origin chiefly tendinous in structure. In the lumbar region, it is larger, and forms a thick fleshy mass. Further up, it is subdivided into three columns. These gradually diminish in size as they ascend to be inserted into the vertebræ and ribs. The erector spinæ arises from the anterior surface of a broad and thick tendon. It is attached to the medial crest of the sacrum, to the spinous processes of the lumbar and the eleventh and twelfth thoracic vertebræ and the supraspinous ligament, to the back part of the inner lip of the iliac crests, and to the lateral crests of the sacrum, where it blends with the sacrotuberous and posterior sacroiliac ligaments. Some of its fibers are continuous with the fibers of origin of the gluteus maximus. The muscular fibers form a large fleshy mass that splits, in the upper lumbar region, into three columns, viz., a lateral (Iliocostalis), an intermediate (Longissimus), and a medial (Spinalis). Each of these consists of three parts, inferior to superior, as follows: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Erector spinae muscles」の詳細全文を読む スポンサード リンク
|