Transactions . Fiy. li. Transverse vertical section through skull of new-born,left side in a plane ^^ incli more anteriorly to right. J. Jugularbulb at its greatest diameter. Lateral sinus turns forwardinto jugular vein. L. L. Lateral sinus. T. Transverse processof atlas. M. Medulla and pons. Facial nerve emerges % inchanterior to plane of this section at F. skull is only io to -^s inch. (In the adult it is -^ inch ormore.) In this distance the facial nerve in the new-bornfollows a coiuse of nearly 4o deirrees from the vertical. Itemerges from tin- skull 4 inch behind, -s in<-h below am
Transactions . Fiy. li. Transverse vertical section through skull of new-born,left side in a plane ^^ incli more anteriorly to right. J. Jugularbulb at its greatest diameter. Lateral sinus turns forwardinto jugular vein. L. L. Lateral sinus. T. Transverse processof atlas. M. Medulla and pons. Facial nerve emerges % inchanterior to plane of this section at F. skull is only io to -^s inch. (In the adult it is -^ inch ormore.) In this distance the facial nerve in the new-bornfollows a coiuse of nearly 4o deirrees from the vertical. Itemerges from tin- skull 4 inch behind, -s in<-h below amiabout 1 J inch actual distance from the bony tympanic Fij;. ;{. Transverse vertical section through itMiu)oral bone ofnew-born, same as in preceding figure, but on left side a sectionhas been made in a plane |)arallel to last. V* incii Superior semi-circular canal. H. Horizontal semi-circularcanal. F. Facial nerve. T. Tympanic cavity. 13. .lugularbulb, anterior expanded portion. 424 BUAISLIN. In reacliiii<i the jugular bulb in the young infant no bonyfloor of the auditory canal exists to be cut away and thevessel in its course through the bone does not extend sofar anteriorly. The bony base of the cranium of the new-born is thinner and the vessel in its forward and downwardcourse emerges rather posteriorly to the tympanic floor. Inthe infant during the first months, at least, exposure of thesigmoid sinus may be carried downwards to the jugular bulband its posterior portion may be exposed with less difficultythan in the adult.
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Keywords: ., boo, bookcentury1800, bookdecade1860, booksubjectear, bookyear1868
