Method for measuring vagina dimensions

In a trial and error method for measuring the effective diameter of the vaginal sphincter muscle of an animal of the type having a vagina terminating at the posterior end in a normally closed vulva and at the anterior end in a normally closed cervix and having a vaginal sphincter muscle therebetween using a device with a nose cone portion having a rounded blunt free end mounted to an elongate handle, said nose cone portion including an intermediate ring of maximum diameter, the steps of

• a. grasping one of said measuring devices by the handle and inserting the nose cone portion through the animal's vulva into the animal's vagina until said intermediate ring passes anterior to said sphincter muscle, and
• b. repeating step (a) with different measuring devices having intermediate rings of successively increased diameters until a measuring device is tried which causes a marked build-up of resistance against anterior movement of the device upon contact of said intermediate ring with the sphincter muscle and a distinct release of the resistance after passage through the muscle.