Basically, a hymen is a very thin layer of skin - like tissue on the inside of the vagina (hmm...how many of U out there REALLY use this word?) just past the major and minor libia, which is the outer most and not so outer most 'vaginal lips' covering that area.
No, I do not know why the hymen is there, eventhough I can guarantee all that is certainly wasn't created by God for guys to tell if their brides to be were virgins!!!
What is certain is that a whole range of activities can easily tear the hymen...from something as simple as doing (real by definition of a physiotherapist that is) stretching exercises to riding a bicycle to little girls running around vigorously at the playground!!!
As for your question, technically, yes, masturbating can tear a hymen if there's any intrusion into the vaginal channel, or if there's enough stretching, trashing and writhing about.
I wanted to say something earlier like go check a good biology book, but then realise that a bio book won't really tell you much simply because in biological terms, the difference between a torn and intact hymen has NO health concerns or biological importance whatsoever!!! The only importance given to a 'torn' or 'untorn' hymen seems to be for the totally ridiculous judgement of whether a girl is still a virgin or not, just to satisfy whatever male pride/ego needs there be!
The FINAL nmessage to all girls out there: If you wanna mustabate, and enjoy doing it...just be sure to wash your hands carefully and enjoy yourselves!
hahahahaha..that i donno.....i didnt give birth before.... but generally the "hole" can be strecth to a "fuji apple - big" radia. Try mating with a elephant, sure giving birth like peeing.
