Cloacal morphology in its relation to genito-urinary and rectal diseases(With 54 plates and 93 illustrations.) . Fig. 8.—Cross-section throughthe middle of the tail (Fig. 4,a). M, muscle; M, degenerat-ing muscle; A, artery; A^,nerve; L is placed on the leftand R on the right of theappendage. X Fig. 9.—Caudal region of embryo of14 mm. (No. 144 of Dr. Malls collec-tion), combined from several sagittal sec-tions. An., anus; Ao., caudal aorta { media); Ca. fil., caudal filament;Ch., notochord; Med., medullary cord;5. u§., sinus urogenitalis; V. 32, thirdcoccygeal vertebra; 36, sevent
Cloacal morphology in its relation to genito-urinary and rectal diseases(With 54 plates and 93 illustrations.) . Fig. 8.—Cross-section throughthe middle of the tail (Fig. 4,a). M, muscle; M, degenerat-ing muscle; A, artery; A^,nerve; L is placed on the leftand R on the right of theappendage. X Fig. 9.—Caudal region of embryo of14 mm. (No. 144 of Dr. Malls collec-tion), combined from several sagittal sec-tions. An., anus; Ao., caudal aorta { media); Ca. fil., caudal filament;Ch., notochord; Med., medullary cord;5. u§., sinus urogenitalis; V. 32, thirdcoccygeal vertebra; 36, seventh coccygealvertebra; V. c. i., caudal portion of venacava inferior (F. sacralis media). X91. to disappear—leaving no trace in the adult. From these bare facts we can recognize thetrue vertebral nature of the coccygeal bones as vestigeal structures—the remains of com-plete vertebrae in the ancestral stock of the human species. The facts set forth in thisbrief sketch point unmistakably to the conclusion that the cloacal-coccygeal territoryhas suffered extensive transformation in its descent to the human condition and to thefurther conclusion that it is still undergoing change and reduction. The practitioner aswell as the surgeon, should have a thorough knowledge of the phylogenetic as
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishercincinnatitheautho
