This article is from healthcentral.com. The emphasis on the fifth paragraph is added.
MR IMAGES SHOW ANATOMY OF SEX
December 17, 1999
NEW YORK (Reuters Health) -- Dutch scientists have produced a new type of adult film. Using magnetic resonance imaging (MRI), they have produced images of lovemaking. Results of the experiment overturn conventional ideas about the anatomy of sexual intercourse, the researchers report.
Dating back to at least Leonardo da Vinci, people have attempted to illustrate the anatomy of sexual intercourse between a man and a woman, but studying exactly how the body changes during sex has been difficult, according to a team of researchers led by Dr. Willibrord Weijmar Schultz, of the University Hospital Groningen in the Netherlands.
In their study, Schultz and colleagues used MRI scans, commonly used to diagnose a number of illnesses, to view the anatomy of male and female genitals during sexual intercourse. The researchers also used the scan on women who stimulated themselves.
Making love in a hollow tube certainly is not the most romantic setting, but eight couples (including two who needed the help of the impotence drug Viagra) and three single women were up to the task, the authors report in the December 18-25 issue of the British Medical Journal.
The experiments yielded several observations about the anatomy of sexual intercourse and female sexual arousal. First, when a couple is in the missionary position (woman lying on her back, man on top), the penis is slightly curved like a boomerang, not S-shaped as previously thought.
Second, the uterus does not become larger when a woman is sexually aroused, as stated by the sex researchers Masters and Johnson. Finally, when a woman brings herself to sexual arousal, the uterus rises and the front wall of the vagina lengthens.
MRIs of sexual intercourse may do more than simply produce interesting images, Schultz told Reuters Health. Learning more about the anatomy of sex may produce insights into infertility, for which the cause is unknown about 15% of the time, according to the Dutch researcher.
In a footnote, the research team thanks the study volunteers "for their cooperation, laughter, and permission to publish intimate MR images of them." They also thank hospital officials for "the intellectual courage to allow us to continue this (research)."