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. On the theory and practice of midwifery . st thickness two and a half inches. M. Baude-locque found that the thickness of this bone scarcely varies a line, evenin deformed pelves. Its specific gravity is small, owing to its spongytexture; so that, for its size, it is probably the lightest bone in the external surface is rough and convex, exhibiting four or five spinousprocesses like those of the vertebras, but smaller, and diminishing in sizeas they descend. Anterior to these we find a continuation of the spinalcanal, containing the cauda equina, with four holes on each side commu-n
. On the theory and practice of midwifery . st thickness two and a half inches. M. Baude-locque found that the thickness of this bone scarcely varies a line, evenin deformed pelves. Its specific gravity is small, owing to its spongytexture; so that, for its size, it is probably the lightest bone in the external surface is rough and convex, exhibiting four or five spinousprocesses like those of the vertebras, but smaller, and diminishing in sizeas they descend. Anterior to these we find a continuation of the spinalcanal, containing the cauda equina, with four holes on each side commu-nicating with it, for the transmission of nerves. Its internal surface (2) issmooth, and concave to the amount of half an inch, crossed by four trans-verse lines, marking the former division of its bones by cartilage: hereare also four pairs of holes sloping outwards, through which pass nervousfilaments, which afterwards form part of the great sciatic nerve. Theupper edge of this bone completes the brim of the pelvis; the oval shape Fig. of which, however, is broken by the projection of the central portion,—the promontory of the sacrum (1). The lateral surfaces (3) are rough,uneven, and covered with a thin layer of cartilage; the irregularities cor-respond to similar ones in the ilium, and with them form the sacro-iliac OF THE JOINTS OF THE PELVIS. 39 synchondroses. This is probably the most important bone in the pelvis,obstetrically considered, inasmuch as it forms a great portion of the brimand cavity, and enters largely into the various deformities of the pelvis. It is connected superiorly with the last lumbar vertebra, laterally withthe ossa ilia, inferiorly with the os coccygis, and by ligaments with theossa ischia. 9. The Os Coccygis, or huckle-bone (4), is the continuation and ter-mination of the os sacrum and vertebral column. It is formed by four orfive points of ossification in the foetus, which do not afterwards unite, butare tipped with cartilage, and moveable
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Keywords: ., book, bookcentury1800, booksubjectmidwifery, booksubjectpregnancy