A system of dental surgery / by Sir John Tomes.

  • John Tomes
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: A system of dental surgery / by Sir John Tomes. Source: Wellcome Collection.

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    slender spicula, giving to the border a rough snrface^ ■which, although well marked in many dry specimens, is much more strongly pronounced before the bono is allowed to dry, and the partly-calcified spicula to become contracted by the loss of moistiire. If these grooves are traced through a series of specimens of progressive ages, commencing with the foetal jaw, it will be seen that those about the coronoid process indicate the course in which that part has ad- vanced; a line which, it Avill subsequently be shown, is per- manently marked in the adult jaw by the external oblique line. Then, again, a similar line of grooves indicates the course which has been taken by the articular process in its progressive growth upwards and backwards. Indeed, this line is also indicated by the surface being slightly raised, there being a distinct rounded eminence along the outer surface of the jaw, ending in the condyle, which becomes less marked in the adult. Below, and a little posterior to this line, we have the angle of the jaw, the increase in which has been already noted. M, Kolliker has shown that the articular cartilage is of unusual thickness for cartilage so placed; and that, in addition to the usual functions of articular cartilage, it is here subservient to the purposes of development, its office in one respect being similar to the cartilage which in child- hood is placed between the epiphysis and shaft of a long bone. It is not proposed to enter upon the subject of osseous development, until the changes of form and increase of size of the maxillse have been traced from birth to man- hood. But the discovei-y first recorded by M. Kolliker has been mentioned, in order to show that in wliatcver direction the jaw has increased, the increase has been produced by additions to the external surface. Tlierc are no indications of interstitial growth within and throughout the whole sub- stance of the bone. It is not iniusual to find increased size of a bone described as expansion, but the term is not applicable. We may have great increase in the size of the medullary cavity and of the circuuifcrcnce of a long bone,
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