The size of the uterus did not increase during sexual arousal.Conclusion: Taking magnetic resonance images of the male and female genitals during coitus is feasible and contributes to understanding of anatomy.“I expose to men the origin of their first, and perhaps second, reason for existing.”1 Leonardo da Vinci (1452-1519) wrote these words above his drawing “The Copulation” in about 1493 (fig 1).2 The Renaissance sketch shows a transparent view of the anatomy of sexual intercourse as envisaged by the anatomists of his time.
Objective: To find out whether taking images of the male and female genitals during coitus is feasible and to find out whether former and current ideas about the anatomy during sexual intercourse and during female sexual arousal are based on assumptions or on facts. Thirteen experiments were performed with eight couples and three single women.
Methods: Magnetic resonance imaging was used to study the female sexual response and the male and female genitals during coitus.
Results: The images obtained showed that during intercourse in the “missionary position” the penis has the shape of a boomerang and 1/3 of its length consists of the root of the penis.
During female sexual arousal without intercourse the uterus was raised and the anterior vaginal wall lengthened.
4 5 Their most remarkable observations regarding sexual arousal in the woman were the backwards and upwards movements of the anterior vaginal wall (vaginal tenting) and a 50-100% greater volume of the uterus.
This increase disappeared 10-20 minutes after orgasm When sexual excitement without orgasm occurred, the volume returned to normal in 30-60 minutes.
Masters and Johnson presumed that the greater volume of the uterus was due to engorgement with blood However, they qualified their presumption: “In view of the artificial nature of the equipment, legitimate issue may be raised with the integrity of observed reaction patterns.”4 In 1992 Riley et al published an ultrasound study on copulation.6 The images were of relatively poor quality as they used hand held, self scanning equipment, and none of the images was overview.
In the woman the right lactiferous duct is depicted as originating in the right female breast and ending in the genital area.
Even a genius like Leonardo da Vinci distorted men's and women's bodies—as seen now—to fit the ideology of his time and to the notions of his colleagues, who he paid tribute to.