Sex researchers in pursuit of the elusive G-spot are using scanning technology to expand their understanding of the female orgasm.

Scientists at the University Hospital Groningen in the Netherlands took the first-ever magnetic resonance images (MRIs) of study subjects engaged in sexual intercourse. Doctors studied eight couples copulating and three women masturbating to better understand how the male and female anatomies interact.

"The importance of understanding anatomy during sex is [initially for] a purely scientific reason.... Sexology is still a wide open unexplored scientific field," said Willibrord Weijmar Schultz, associate professor of gynecology at the University Hospital Groningen, and lead author of the study. The research results were published in the December issue of the British Medical Journal.

"In the long run these results could have implications for developing ideas related to clinical issues, such as the treatment of infertility and genital dysfunctions," Schultz said.

"The research has significance to those who are interested in the shape of the penis and vagina during intercourse. Further, it adds a truer dimension to the actual physiological and anatomical responses during intercourse," said Dr. William Granzig, president of The American Board of Sexology in Washington. "As such, future research or clinical diagnosis might be enhanced by the techniques explored here."

The MRI scans were not detailed enough to distinguish between the vaginal wall, urethra, and clitoris of the women, so researchers were unable to verify the existence of the Gräfenberg spot (G-spot), the widening of the vaginal canal, or a reservoir of fluid that might indicate female ejaculation.

However, the study did reveal evidence that the uterus was not enlarged during intercourse -- a finding contrary to research Masters and Johnson reported in their 1966 book Human Sexual Response. The Dutch researchers found that although the uterus was raised and the anterior vaginal wall was lengthened, the uterus remained the same size.