OCR Text |
Show 770 MR. ST. GEORGE MIVAKT ON THE [June 27, second dorsal vertebrae, and from the transverse processes of the last four cervical vertebrae. It is inserted into the supraoccipital and into the parietal process. Complexus minor (figs. 2 & 2A, C.Mii). A muscle placed externally to the last arises from the transverse processes of tbe last four cervical vertebrae. It is inserted, by strong tendinous fibres, into the end of the parotic process, but gives off from its outer side a fasciculus (figs. 2 & 2 A , X) which passes to the postero-external end of that depending process of the basioccipital which bounds internally the posterior part of the eustachian aperture. Cervicalis ascendens. This (fig. 2 A, C.A.), as has been said, is the continuation forwards of the sacro-lumbalis. It is inserted by tendinous fibres into the outer sides of the cervical ribs and into the transverse processes of the four anterior cervical vertebrae (including the atlas), which have no ribs. Spinalis colli (fig. 2 A , S.C.). The innermost portion of the deep part of the dorsal extensor mass fills the groove between the spinous and articular processes of the cervical vertebrae. It ends at the occiput, where it enters the deep fossa between the supraoccipital and the diverging parietal processes. Rectus capitis posticus major. A more or less distinct muscular fasciculus (fig. 2 A, R. P. Mi) arises from the spinous process of the axis, and is inserted into the supraoccipital. Scalenus. The scalene muscles appear to be represented by a very obscurely separable small muscular mass, which extends from the transverse processes of the first four cervical vertebrae to the anterior margin of the first cervical rib. It lies between the cervicalis ascendens and the rectus capitis anticus major (fig. 2 A, S C ) . The longus colli arises from the ventral surfaces of the bodies of the atlas and two following cervical vertebrae. It is inserted into the same surfaces of the next four cervical vertebrae and into the last three cervical ribs near their origins. Rectus capitis anticus major (fig. 2 A , R. A. M.). This muscle arises from the posterior end of the under surface of the basioccipital, and largely from the process bounding internally the posterior end of the eustachian aperture. Passing backwards it is inserted into the bodies of the cervical vertebrae from the fourth to the seventh inclusive, and finally into the anterior margin of the deep surface of the rib of the seventh cervical vertebra. Rectus abdominis. The abdominal muscles are largely developed, both as regards superficial extent and number, as there appear to be no less than three layers of the external oblique muscle. The rectus is broad, but rather ill-defined superficially as to its outer margin, which, however, is readily seen on its internal surface. It arises by a strong tendon from the posterior end of the ventral surface of the symphysis ischii (figs. 13 & 14, R.). Thence it runs forwards along the middle line of the belly, and is inserted into the posterior margin of the last sternal rib, whence it is continued to the last sternal rib but one, where it is conterminous with the pectoralis major (fig. 6, R.), which is apparently its anterior prolongation. |