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Show 0f the Skull. Tm "Pm Book III. Book III. This Bone belonging to the Orriput, is of a Triangular Figure, and.is rare. The Ofliz Temporum are furnilhed with Five Perforations, the Firlt is 62Th, Fm {in difcernible in the 0: film/um, ordained by Nature for the conveyanc e Sgriurgfions andC'omPOj 1y compofed of one, but mofi: commonly of many Bones, fometimes of iii'h‘iripfiiiii' Two, and other times of Three, and now and then of Four: . pf the Fifth pair of Nerves. "21.2%: The Second Perforation is more large and unequal, feared under the rPro- $534,. Rs. Imhis Triangular Bone the Lamdoidal Suture hath lt‘S terminations, as it hiiriiiiic Were made of‘Two crural Procefles, in whichTome Branches pafs crofsways from one Extremity to the other; and 15 fEVeer from-the other Bones, (containing the Two finall Heads onProcefres of the Ocapur) F311"; "flip: Stiloider '1‘ and tranfmitteth the greater Branch of the caroride Artery 1" by Galen "trim which infinuate the-mfelves into the Smart, engraven in the and is common to the Occiput, giving a paiTage to the irregular vein, and the leffer branch of the carotide Artery, and to the Firfi pair of Nerves. 017': orritnt" {irlt Vertebrc of the Neck; this variety of Bones (adornlng the Occipm) is vifible in the Third Month, of which the Rudiments appear only in rhc Second, as being membranous or cartilaginous. In the Fourth Month the Bones being completed, do coalefce into one. This number of Bones ( I conceive) is thus occafioned in the Farm, 33:33" becaufe in the Third Month, the OJ 'Diangulzzre is partly bony, and partfi'mfl: l)' cartilaginous, Whole Particles intercedingr in diverfe places, the imper- ‘h‘""" {(36,} Bones do feem to make many, which are not in truth many difiinét Bones, but parts belonging to one, which is very confpicuous, when the cartilaginous interpofitions, growing bony, fill up the vacurties, rendring the 0; T‘imrgztlare one entire Bone, to which, after it is united, accrefceth a new Bone, which may be fiyled 0! Tricufiidale, touching with one point the 0t Triangle/are, and reaching the Two other toward the affirm be. low; about which may be alfo fometimes obfctved another 0: 'Hituflr- dale, Two of its points, (acofling the mew") do embrace them near their Origcn; and the Third tending toward the OJSphmoider, is not conjoyned to it: This Bone in the divarication of its Sutures, and Procefles, ob- ferveth no fet method, but fporteth in great variety. The firuztion The Ofla 'flzmpomm are feared on each fide of the Head, of which the exSi‘Sffilflfif ternal parts are called Ofla Squdmmqfa, as being joyned after the manner of Pk" Scales to the under Bones, which are called Ofliz Tetra/21, by reafon of their great hardnefs : and are fo thin in the middle, that they feem tranliaarcnt, mm"; when expofed to a Candle; and in their upper part they refemble the Hawk 0f the Skull. Segment of a. Circle: and are adorned with divers Procefles,oneofwhich and the inoft remarkable, is compofed of the Prominencies of Two Bones, conjoned in an oblique Suture, and its Polierior part being a Ptocefs of the 0s Temporuw, is emitted toward the Face, with a crooked Apaphyfis and by the conjunction of a Procefs with the upper Mandible, doth conLn" 5- {brute the GI jugalc + wrfely mflituted by Nature for the defence of the temporal Mufcle, fafely repofed under its Arch. From the inferior Region of thefe Bones, are derived the Mammiformc Procelics, which being of a Pyramidal Figure, begin with greater Bafes, and end into obtufe Angles. From thefe Bones alfo arife Tw0 fmaller Procefl‘es, or rather APP" dices, taking their Origens in lefs Bares then the other, and terminate into more acute Angles. The Ofliz Petroflz are endowed with Three eminent Sinus, one oftllem receiveth into its bofom, the obtufe Procefs of the lower Mandible, whiCll is united to the Dr @etrofum by a membranous Ligament. The other being common to the '0: Occipitir, doth render inwardly hoilow the back part of the Procefs, belonging to the OJ" rPetrafum. The Third is the mofi: ufeful and largefi Sim", containing the auditory~ Nerve. . The to the Brain, by the Fifth hole of the Or Sphenoz‘der. The Third Perforation, relating to the 0; Temporum is alfo confiderabie, y The Fourth Perforation hath its feat between the q'roteflim IVfammifizrmir, and Styloider, and tranfmitteth through a long Channel, the harder branch of the Fifth pair of Nerves. Having given a. defcription of the Bones of the Temples, Iwill make Tfhcofitsns bold to fliew the Firfi origination of them ; which in the Two firft Months Stri'fi'fgf.' of their imperfect production, are araied with more foft attire of a membra- 9"" nous Compage, as their ruder delineation tending to a bony fubltance. In the Third Month the q'rocefl'm Zygomaticm, being an Appendix of 338,525" the upper Mandible, appeateth wholly concreted into Bone, while all the "flu?"- other Bones of the Temples retain their Cartilaginous Nature; except the m ' Circle feared in the 0: Petrofum ( to which the Membrane of the Ivmpanum is affixed) which putteth on the fubflance of a Bone fo finely fpun, that it is drawn out as {mall as minute Filaments. The Praceflm Styloider is a Cartilaginous point, (lying along, and rafting T‘h: Origen near the bony Circle) and is ereéted long after its Birth, and is afterward 3:12:52."' turned into a tender Bone. W" In the Fourth Month the 0: Squammafnm may be diicovered, and the The Rudi- Perforation of the Eat to be rendred bony, after the manner of a Long un- afifiifi. equal Line, drawn out fomewhat beyond the bony Circle. M'- |
