. A treatise on practical anatomy: for students of anatomy and surgery . ipital bone is situated at the back and base ofthe skull. It is strongly curved, forming an arch ofabout one-third of a circle. Viewed posteriorly it isdiamond-shaped. It presents for examination two su-perior lateral and two inferior lateral borders, an exter-nal and an internal surface, and a basilar process. Thesuperior borders meet above at the apex of the bone, andarticulate with the posterior borders of the parietal bonesby means of tooth-like processes. The inferior borders THE OCCIPITAL BONE. 17 articulate with th
. A treatise on practical anatomy: for students of anatomy and surgery . ipital bone is situated at the back and base ofthe skull. It is strongly curved, forming an arch ofabout one-third of a circle. Viewed posteriorly it isdiamond-shaped. It presents for examination two su-perior lateral and two inferior lateral borders, an exter-nal and an internal surface, and a basilar process. Thesuperior borders meet above at the apex of the bone, andarticulate with the posterior borders of the parietal bonesby means of tooth-like processes. The inferior borders THE OCCIPITAL BONE. 17 articulate with the temporal bones; the upper half withthe mastoid portion, the lower lialf with the petrous partof the temporal bone. The upper lialf merely abutsagainst the mastoid portion; the lower half has project-ing a well-marked process of bone—the jugular process—which articulates with the jugular surface of thepetrous portion of the temporal. Anterior to the jugularprocess is the jugular notch, which, with the jugularfossa on the petrous portion of the temporal, forms the. Fig. 6.—OcciprTAL Bone, Outek Surface. jugular foramen for the transmission of the lateral sinusdown the neck. The inferior lateral borders are sepa-rated anteriorly by a thick quadrilateral process of bone,the basilar process, which, in the developing skeleton,articulates with the sphenoid, but after the twenty-fifthyear the layer of cartilage between them ossifies and theoccipital and sphenoid form one bone. The outer sur-face is convex, and midway between the apex and fora-men magnum presents the external tuberosity for theattachment of the ligamentum nuchae; branching out 18 PRACTICAL ANATOMY. from each side of this are the superior curved from the tubercle to the foramen magnum is asharp ridge of bone, the external crest, from which passes,midway between the superior curved lines and the fora-men magnum, the inferior curved lines. The boneabove the superior curved lines is smooth; below it is
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomy, bookyear1891
