Quain's elements of anatomy . nous wall Avhich is continuous with the parachordalcartilage and seems to take the place of that cartilage as a part of thegeneral cranial wall. While the base of the cranium, to the extent already mentioned, iscartilaginous in its origin, the lateral and upper walls are chiefly ofmembranous formation, as in the squama occipitis, the squamo-zygomaticof the temporal, the parietal and the frontal bones. The membranous tissue in which these flat bones of the cranial vaultare formed is regarded by Kolliker as of dermal origin, and the bones asbelonging to the group of
Quain's elements of anatomy . nous wall Avhich is continuous with the parachordalcartilage and seems to take the place of that cartilage as a part of thegeneral cranial wall. While the base of the cranium, to the extent already mentioned, iscartilaginous in its origin, the lateral and upper walls are chiefly ofmembranous formation, as in the squama occipitis, the squamo-zygomaticof the temporal, the parietal and the frontal bones. The membranous tissue in which these flat bones of the cranial vaultare formed is regarded by Kolliker as of dermal origin, and the bones asbelonging to the group of investing bones. Their formation is however 810 FEAMEWORK OF THE BODY. in part supplemented by the extension upon them from below of a plate&f cartilage which is placed internally to the membranous matrix. The trabecute stretch forward to the anterior extremity of the head,and maintain the foremost place in the seat of the nasal cartilages andexternal apertures of the nose. Behind these the coalesced trabeculee Fig. Fig. 708.—View from below op the carti-laginous BASE OF THE CRANIUM WITH ITSOSSIFIC CENTRES IN A HUMAN FCETUS OP ABOUT FOUR MONTHS. (From Huxley, slightlyaltered.) The bone is dotted to distinguish it from thecartilage, which is shaded with lines. 1, thebasilar part, 2, the condyloid or lateral parts,and 3, 4, the tabular or superior part of theoccipital surrounding the foramen magnum ; 5,centres of the presphenoid on the inside of theoptic foramen ; 6, centres of the post-sphenoid ; 7, centres of the lesser wings or orbito-sphenoid ; 8, septal cartilage of the nose ; 9 and 10, partsof the labyrinth. form a narrow ethmo-vomerine car-tilage, the nasal septum, round the backof which the vomer is formed as abony splent covering ; while in the hinder lyre-shaped interval of theseparated trabecular is placed the infundibulmn in connection with thepituitary body. From the side of the presphenoid cartilage the matrix of the orbito-sphenoids or lesser wings, contai
Size: 1452px × 1721px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
