336 
ATllESIA ANI ET RECTI. 
abdomen appears distended, colic sets in, the patient stops sucking, 
strains and attempts to pass fteces, and when the anus is examined it is 
Fig. 152.— Congenital malformation—atresia ani in the bitch (semi-diagrammatic). 
found there is no opening. If the anus alone is imperforate, the skin 
projects at the centre of the sphincter, rectal contents may even be 
distinctly felt beneath it; but, when the walls of the rectum are also 
Fig. 153. Congenital malformation—atresia ani et recti in the bitch (semi-diagrammatic). 
adherent this projection is wanting, and either the anus is visibly closed 
or, on introducing the finger or a probe, an obstruction is felt not far 
from the external orifice. In recto-vaginal fistula excrement escapes by 
the vagina, and the communication between the upper vaginal wall and 
rectum can usually be discovered with the finger or probe. 
