. Human embryology and morphology. Embryology, Human; Morphology. THE CRANIUM. 169 extremities fuse round the anterior termination of the notochord with the parachordal cartilages. The buccal part of the pituitary grows into the cranial cavity in front of the notochord and keeps the two cartilages apart; but in front of the pituitary the two bars fuse in the middle line. The mesial fused parts of the trabeculae grow into the mesial nasal processes of which they form the skeletal basis and become transformed into the primitive cartilaginous septum of the nasal cavities (Figs. 136 and 3, p. 3).
. Human embryology and morphology. Embryology, Human; Morphology. THE CRANIUM. 169 extremities fuse round the anterior termination of the notochord with the parachordal cartilages. The buccal part of the pituitary grows into the cranial cavity in front of the notochord and keeps the two cartilages apart; but in front of the pituitary the two bars fuse in the middle line. The mesial fused parts of the trabeculae grow into the mesial nasal processes of which they form the skeletal basis and become transformed into the primitive cartilaginous septum of the nasal cavities (Figs. 136 and 3, p. 3). The posterior segment of the median fused bars forms the cartilaginous basis of the pre-sphenoid and basi-sphenoid (Fig. 136). From the trabeculae four lateral processes or wings grow out on each side (Fig. 136). The pos- terior, which is small at first, forms the great wing of the sphenoid and external pterygoid plate; the second is originally large, and forms the small wings (orbito-sphenoids) ; the third and fourth outgrowths are closely joined,—they form the lateral masses of the ethmoid and alar cartilages of the nose (Fig. 6, page 6). The nasal bones, the lachrymal and ascending nasal processes of the superior maxilla, develop in the membrane over the lateral nasal wings of the trabeculae, in the same way as the vomer develops over the cartilage of the septum. Development of the Sphenoid (Fig. 137).—At birth the sphenoid bone, which is developed by ossification of the posterior <rbito-sph. presphenoid/ ^opthfon ali-sphen. for. '. pteryg. proc. for. ovale int. pter. bas'-sPh Fig. 137 —The Sphenoid in a foetus of 4 months. The Centres of Ossification are deeply shaded. (After Sappey.) parts of the trabeculae cranii, consists of three parts, the great wings being separated from the rest of the bone. The sphenoidal turbinate bones, afterwards inflated by the development. Please note that these images are extracted from scanned page images that may have been dig
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
