Henry Gray (18251861). Anatomy of the Human Body. 1918.
The Lumbodorsal Fascia (fascia lumbodorsalis; lumbar aponeurosis and vertebral fascia).The lumbodorsal fascia is a deep investing membrane which covers the deep muscles of the back of the trunk. Above, it passes in front of the Serratus posterior superior and is continuous with a similar investing layer on the back of the neckthe nuchal fascia.
In the thoracic region the lumbodorsal fascia is a thin fibrous lamina which serves to bind down the Extensor muscles of the vertebral column and to separate them from the muscles connecting the vertebral column to the upper extremity. It contains both longitudinal and transverse fibers, and is attached, medially, to the spinous processes of the thoracic vertebræ; laterally to the angles of the ribs.
In the lumbar region the fascia (lumbar aponeurosis) is in two layers, anterior and posterior (Figs. 388,409). The posterior layer is attached to the spinous processes of the lumbar and sacral vertebræ and to the supraspinal ligament; the anterior layer is attached, medially, to the tips of the transverse processes of the lumbar vertebræ and to the intertransverse ligaments, below, to the iliolumbar ligament, and above, to the lumbocostal ligament. The two layers unite at the lateral margin of the Sacrospinalis, to form the tendon of origin of the Transversus abdominis. The aponeurosis of origin of the Serratus posterior inferior and the Latissimus dorsi are intimately blended with the lumbodorsal fascia.
FIG. 388 Diagram of a transverse section of the posterior abdominal wall, to show the disposition of the lumbodorsal fascia. (See enlarged image)
The Splenius capitis(Fig. 409)arises from the lower half of the ligamentum nuchæ, from the spinous process of the seventh cervical vertebra, and from the spinous processes of the upper three or four thoracic vertebræ. The fibers of the muscle are directed upward and lateralward and are inserted, under cover of the Sternocleidomastoideus, into the mastoid process of the temporal bone, and into the rough surface on the occipital bone just below the lateral third of the superior nuchal line.
The Splenius cervicis (Splenius colli) (Fig. 409)arises by a narrow tendinous band from the spinous processes of the third to the sixth thoracic vertebræ; it is inserted, by tendinous fasciculi, into the posterior tubercles of the transverse processes of the upper two or three cervical vertebræ.
Variations.The origin is frequently moved up or down one or two vertebræ. Accessory slips are occasionally found.
Nerves.The Splenii are supplied by the lateral branches of the posterior divisions of the middle and lower cervical nerves.
Actions.The Splenii of the two sides, acting together, draw the head directly backward, assisting the Trapezius and Semispinalis capitis; acting separately, they draw the head to one side, and slightly rotate it, turning the face to the same side. They also assist in supporting the head in the erect position.
The Sacrospinalis (Erector spinæ) (Fig. 389), and its prolongations in the thoracic and cervical regions, lie in the groove on the side of the vertebral column.