<P> It is normal for humans to pass flatus through the rectum , although the volume and frequency may vary greatly between individuals . It is also normal for intestinal gas passed through the rectum to have a characteristic feculent smell , although this too may vary in concentration . Flatus is brought to the rectum by specialised contractions of the muscles in the intestines and colon . The noises commonly associated with flatulence ( `` blowing a raspberry '' ) are caused by the vibration of anal sphincters , and occasionally by the closed buttocks . Both the noise and smell associated with flatus leaving the anus can be sources of embarrassment or comedy in many cultures . </P>
<P> It is normal for humans to pass flatus through the rectum , although the volume and frequency may vary greatly between individuals . It is also normal for intestinal gas passed through the rectum to have a characteristic feculent smell , although this too may vary in concentration . Flatus is brought to the rectum by specialised contractions of the muscles in the intestines and colon . The noises commonly associated with flatulence ( `` blowing a raspberry '' ) are caused by the vibration of anal sphincters , and occasionally by the closed buttocks . Both the noise and smell associated with flatus leaving the anus can be sources of embarrassment or comedy in many cultures . </P>
where does the sound of a fart come from
where does the sound of a fart come from
caused by the vibration of anal sphincters , and occasionally by the closed buttocks
caused by the vibration of anal sphincters , and occasionally by the closed buttocks