A collection of engravings, designed to facilitate the study of midwifery : explained and illustrated / By James Hamilton, junior.

  • Hamilton, James, -1839.
Date:
1796
    4
    Ft a. /.
    PLATE III. HEAD OF THE SKELETON OF A NEW-BORN CHILD OF THE ORDINARY SIZE, AT THE FULL PERIOD OF UTERO-GESTATION. i iGURF. i\Jl, Exhibits the head fo much inclin- ed to one hde, that a view of the bafe of the cra- nium is given. A, The occipital bone. B, The right frontal bone. C, The right parietal bone. D, The foramen magnum. This figure is chiefly defigned to communicate an idea of the general appearance of the foetal Ikull. The partic ular pofiuon in which it is repre- fented, was chofen in order that the fituation of the foramen magnum might be feen. It is owing to the circumftance of that opening being nearer to the occiput than to the face, that the vertex is pu died fore moll during the procefs of natural la- bour. . • / Figure id, Represents the head placed in fuch a
    a fituation that the fuperior part of the cranium is feen. A A, The protuberances of the parietal bones, diftant from each other about three inches and an half, and forming the fhort diameter of the head. B, The anterior fontanelle. C, The pofterior fontanelle. E D, The long diameter of the head, viz. from the frontal to the occipital bone, meafuring about four inches and an half. This figure is intended to fhow the dimenfions of the long and fhort diameter of the head, and the iituation of the anterior and pofterior fontanelles. Although the diftance between the parietal pro- tuberances A A be three inches and an half, that is not to be regarded as the length of the fhort diameter; for in confequence of the parietal bones being conneded by a membranous fubftance, the protuberances are capable of being made to ap- proach each other, the edges of the bones overlap- ping, fo as to reduce the diameter between them to three inches. The effedt of the cotnpreffion of the head, is ren- dering the foetus infenfible ; and hence-, duiing labour it is a paffive body only. It is from having overlooked this circumftance, that the ftrange do&rine of the foetus in utero being deftitute of fenfation has been advanced. The
    -The bieadth of the membranous fubftance in- terpofed between the parietal bones, being great- er than of thofe which conned the other bones; affords a preemption, that the head is capable of being more diminiflied in the diredion of the fiiort diameter than in any other; a fad, which the ex- periments of M. Bandeloque have fully eltablifh- ed. Both figures were drawn from a dried prepara- tion, on which account, the appearance of the pa- rietal bone, next the temporal bone in figure firft, and the rugous appearance in the membranous lubftance conneding the feveral bones in figure fecond, are peculiarities. I B