Almost 30 years after the intricate web of nerves inside the penis was plotted out, the same mapping has finally been completed for one of the least-studied organs in the human body – the clitoris.
As well as revealing the extent of the nerves that are crucial to orgasms, the work shows that some of what medics are learning about the anatomy of the clitoris is wrong, and could help prevent women who have pelvic operations from ending up with poorer sexual function.
The clitoris, responsible for sexual pleasure, is one of the least studied organs of the human body. Cultural taboo around female sexuality has held back scientific investigations and the clitoris did not even make it into standard anatomy textbooks until the 38th edition of Gray’s Anatomy was published in 1995.
A Melbourne urologist, Helen O’Connell, says the clitoris has been ignored by researchers for far too long. “It has been deleted intellectually by the medical and scientific community, presumably aligning attitude to a societal ignorance,” she said.
To get a better idea of the inner workings of this key pleasure-related organ, Ju Young Lee, a research associate at Amsterdam University Medical Center in the Netherlands, and her colleagues used high-energy X-rays to create 3D scans of two female pelvises that had been donated through a body donor organ programme.
The scans revealed in 3D the trajectory of the five complex tree-like branching nerves running through the clitoris in unprecedented detail, the widest 0.7mm across. The work has been reported on the preprint server bioRxiv and has not yet been peer reviewed.
“This is the first ever 3D map of the nerves within the glands of the clitoris,” said Lee. She is amazed it has taken so long, considering a similar level of knowledge regarding the penile gland was reached back in 1998, 28 years ago.
Lee and her colleagues show that some branches of clitoral nerves reach the mons pubis, the rounded mound of tissue over the pubic bone. Others go to the clitoral hood, which sits over the small, sensitive, external part of the clitoris – the glans clitoris – which is just 10% of the total organ. Other nerves reach the folds of skin of the vulva, the labial structures.
Previous research had indicated that the big dorsal nerve of the clitoris gradually diminished as it approached the glans. However, the new scans appear to show that some of what medics have been learning in anatomy is wrong and the nerve continues strongly all the way to the end.
“I was especially fascinated by the high-resolution images within the glans, the most sensitive part of the clitoris, as these terminal nerve branches are impossible to see during dissection,” said Georga Longhurst, the head of anatomical sciences at St George’s, University of London.
O’Connell, who published the first comprehensive anatomical study of the clitoris in 1998, said the findings were crucial to understanding the female sensory mechanism underlying arousal and orgasm via stimulating the clitoris. “Orgasm is a brain function that leads to improved health and wellbeing as well as having positive implications for human relationships and possibly fertility,” she said.
The mapping of clitoral nerves is likely to inform reconstructive surgery after female genital mutilation, one of the most extreme examples of cultural misogyny. According to the World Health Organization, more than 230 million girls and women alive today in 30 countries in Africa, the Middle East and Asia have undergone such mutilation, in which the visible part of the clitoris may be removed, along with parts of the labia.
The practice has no health benefits and can result in issues including severe bleeding, infection, problems urinating, menstrual difficulties and complications in childbirth.
About 22% of women who undergo surgical reconstruction after mutilation experience a decline in orgasmic experience after their operation, so a better understanding of how far the nerves extend could reduce that percentage, said Lee.
O’Connell said the work could also inform surgery to treat vulvar cancer, gender reassignment surgery and genital cosmetic surgeries, such as labiaplasty, which increased in popularity by 70% from 2015 to 2020.
Lee is hoping to open a clitoris exhibition within Amsterdam University Medical Center to help expand knowledge about the clitoris, inspired by the Vagina Museum in London.