OCR Text |
Show 1894.] ANATOMY OF PALAMEDEA CORNUTA. 539 the front edge of the ileum, becomes tendinous in the middle, and then is inserted by fleshy fibres on to the lateral surface of the vertebral spine next in front; the next anterior part arises tendi-nously from the spinous process of the most posterior uncovered dorsal vertebra, and is inserted on to the vertebra next in front; then follow two of precisely similar relations ; the next is carried on to the dorsal surface of the longissimus dorsi, as also is the last or most anterior portion. Ileo-costalis.-This complex muscle lies laterally to the foregoing muscle; it is fused at the edge with its fibres. It arises from the ileum and from the transverse process beside the attachment of the rib; twTo similar slips in front of this arise from the transverse process and from the adjacent surface of the rib. The ends of the slips are inserted partly ou to the surface of the ribs and partly pass on to the lateral musculature of the neck. Cervicalis aseendens.-This is the lateral muscle anterior to the ileo-costalis. It consists of five distinct slips arising from the transverse processes of vertebrae xvi.-xi. with the exception of xn. The two posterior are inserted on to the vertebrae next in front; the next two are inserted on to the surface of the oblique muscles next in front; the last one on to oblique muscle next but one in front. Behind these slips, which were obvious, there were indications of additional slips both in front and behind, but these were not sufficiently differentiated from the adjacent muscles for separate descriptiou. Longus ceroids.-We were not able to separate this median muscle from the forward continuation of the longissimus dorsi and from the median underlying part of the spinalis complex. Spinalis complex.-This system of muscles lies deeper than the foregoing. It is divisible into three parts. Part I. (sometimes called the spinalis dorsi) arises apparently only from the longissimus dorsi; it gives off six fleshy bellies which increase in length from the posterior to the anterior; they are inserted on to the upper posterior surface of the oblique processes of cervicals x.- xvi. In addition the superior fibres from these heads form a well-marked rounded muscular cord, which runs forward to form the longus colli posticus. Part II. consists of only four well-differentiate slender bellies ; these arise from the spinous processes of cervicals xin.-xv., and they are inserted on to a continuous longitudinal band, the posterior part of which sends slips to the three posterior branches of the spinalis dorsi, while the anterior end is inserted on to the oblique processes of cervicals x., xi., at the roots of the anterior two spinalis dorsi bellies. Part III. (longus colli posticus) arises from the sides of the spinous processes of cervicals II.-XI., and from part I. of the spinalis complex ; it is inserted by digitations which merge with the intervertebral muscles in front of its origins. Rectus capitis posticus.-It arises from the spinous process of atlas and axis; its fibres spread out over the occipital under the complexus. |