. Journal of anatomy . nx, but from this point ofview the saccular part would be the earliest part to grow out, so I have termed the wholethe saccular outgrowth. The Development of the Larynx 179 those of 16 mm. and 22 mm. lengths, under a high power, have suggestedthe possibility of there being some destruction of the lateral lining cellsof this part of the cavity, but this is no more than an occasional suggestion :so the cell thickness seen in the 18 mm. model might be a preliminary todisappearance, or might be the antecedent of the saccular bud. So far as examination of the specimens and mo
. Journal of anatomy . nx, but from this point ofview the saccular part would be the earliest part to grow out, so I have termed the wholethe saccular outgrowth. The Development of the Larynx 179 those of 16 mm. and 22 mm. lengths, under a high power, have suggestedthe possibility of there being some destruction of the lateral lining cellsof this part of the cavity, but this is no more than an occasional suggestion :so the cell thickness seen in the 18 mm. model might be a preliminary todisappearance, or might be the antecedent of the saccular bud. So far as examination of the specimens and models goes, it is onlypossible to say that the saccule develops in the latter part of the secondmonth, and is well marked by the end of the month as a hollow projectionwith an expanded fundus, issuing from the transverse cavity just abovethe position of the chordal nodule. ^ The walls of the original sagittal cleft are pressed together by thegrowing 5th arch mass, and the epithelial lining consequently adheres, so £pi^. Fig. 18.—Shows the apparent protrusion (X) at the lower end of tlie trans-verse cavity of an 18 mm. embryo: the thickening affects the cellularlining and does not seem to increase the breadth of the cavity. The model is seen from the right and behind, and shows the 3rd archelement in the epiglottis. that, in the 5 mm. embryo and in later stages, the cleft is only a potentialone in the greater part of its extent. But the main pressure is apparentlyexerted in the centre of the cleft area, and not so much in the periphery,and, as a result of this, a minute channel runs, from the front end of thefissured opening, along the floor of the cleft: this anterior or ventralchannel is not always open at its front extremity. ^ It was suggested by Kohlbriigge that the saccule represents a visceral cleft or pouch :Kallius quotes this, and considers that, if this view is held, the pouch represented wouldbe the 5tb. It is ajjparent, if the account given here i>J followed, t
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectanatomy, bookyear1867
