The development of the human body; a manual of human embryology . Fig. 44.—Floor of the Pharynxof Embryo B, 7 mm Long. Ep, Epiglottis; Sp, sinus pracervi-calis; t1, anterior, and r2, pos-terior portions of the tongue; /,II, III, and IV, branchial arches.—(His.) THE EXTERNAL FORM OF THE BODY. 93. Fig. 45.—Embryo Lr, mm. Long. am, Amnion; au, auditory capsule; B, belly-stalk; /(, heart; LI, lower and VI, upper limb; Y, yolk-sac.—(His.) 94 THE DEVELOPMENT OF THE HUMAN BODY. special structures. Occasionally, however, a cleft may persistand the thin membrane which forms its floor may becomeperf
The development of the human body; a manual of human embryology . Fig. 44.—Floor of the Pharynxof Embryo B, 7 mm Long. Ep, Epiglottis; Sp, sinus pracervi-calis; t1, anterior, and r2, pos-terior portions of the tongue; /,II, III, and IV, branchial arches.—(His.) THE EXTERNAL FORM OF THE BODY. 93. Fig. 45.—Embryo Lr, mm. Long. am, Amnion; au, auditory capsule; B, belly-stalk; /(, heart; LI, lower and VI, upper limb; Y, yolk-sac.—(His.) 94 THE DEVELOPMENT OF THE HUMAN BODY. special structures. Occasionally, however, a cleft may persistand the thin membrane which forms its floor may becomeperforated so that an opening from the exterior into thepharynx occurs at the side of the neck, forming what is termeda branchial fistula. Such an abnormality is most frequentlydeveloped from the lower (ventral) part of the first cleft;normally this disappears, the upper portion persisting, how-ever, to form the external auditory meatus and tympaniccavity. The embryo i^xvin (Lg) just described measured in length, this measurement, however, being takenalong a straight line and not following the flexure of thebody. It does not represent, therefore, the actual lengthof the body and there is much less difference between itand the next embryo described than is implied by thefigures. T
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
