Mechanics of human sexuality

{{Short description|Biomechanics of human sexual intercourse}}

{{Sex (biology) sidebar}}

The mechanics of human sexuality or mechanics of sex, or more formally the biomechanics of human sexuality, is the study of the mechanics related to human sexual activity. Examples of topics include the biomechanical study of the strength of vaginal tissues{{cite journal |doi=10.1016/S0301-2115(03)00333-6 |last1=Cosson |first1=Michel |last2=Lambaudie |first2=Eric |last3=Boukerrou |first3=Malik |last4=Lobry |first4=Pierre |last5=Crépin |first5=Gilles |last6=Ego |first6=Anne |title=A biomechanical study of the strength of vaginal tissues. Results on 16 post-menopausal patients presenting with genital prolapse |journal=European Journal of Obstetrics, Gynecology, and Reproductive Biology |volume=112 |issue=2 |pages=201–5 |year=2004 |pmid=14746960}} and the biomechanics of male erectile function.{{cite journal |last1=Udelson |first1=Daniel |title=Biomechanics of male erectile function |journal=Journal of the Royal Society Interface |volume=4 |pages=1031–48 |year=2007 |doi=10.1098/rsif.2007.0221 |issue=17|pmc=2396202 |pmid=17478408}}{{cite journal |last1=Mohamed |first1=Ahmed M. |last2=Erdman |first2=Arthur G. |last3=Timm |first3=Gerald W. |title=The Biomechanics of Erections: Two- Versus One-Compartment Pressurized Vessel Modeling of the Penis |journal=Journal of Biomechanical Engineering |date=2010 |volume=132 |issue=12 |doi=10.1115/1.4002794 |pmid=21142318 |doi-access=free}} The mechanics of sex under limit circumstances, such as sexual activity at zero-gravity in outer space, are also being studied.{{cite news |first=Alan |last=Boyle |author-link=Alan Boyle |date=July 24, 2006 |title=Outer-space sex carries complications |url=https://www.nbcnews.com/id/wbna14002908 |publisher=NBC News}}

Pioneering researchers studied the male and female genitals during coitus (penile-vaginal penetration) with ultrasound technology in 1992{{cite journal | last1 = Buisson | first1 = O. | last2 = Foldes | first2 = P. | last3 = Jannini | first3 = E. |author3-link=Emmanuele A. Jannini | last4 = Mimoun | first4 = S. | year = 2010 | title = Coitus as revealed by ultrasound in one volunteer couple | journal = J. Sex. Med. | volume = 7 | issue = 8| pages = 2750–2754 | doi=10.1111/j.1743-6109.2010.01892.x| pmid = 20626602 }} and magnetic resonance imaging (MRI) in 1999, mapping the anatomy of the activity and taking images illustrating the fit of male and female genitals. In the research using MRI, researchers imaged couples performing coitus inside an MRI machine.{{cite journal |last1=Schultz |first1=Willibrord Weijmar |last2=van Andel |first2=Pek |last3=Sabelis |first3=Ida |last4=Mooyaart |first4=Eduard |title=Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal |journal=BMJ |volume=319 |issue=7225 |pages=1596–600 |year=1999 |pmid=10600954 |pmc=28302 |doi=10.1136/bmj.319.7225.1596}} The magnetic resonance images also showed that the penis has the shape of a boomerang, that one third of its length consists of the root of the penis, and that the vaginal walls wrap snugly around it.{{cite news |first1=Thomas |last1=Stuttaford |author-link1=Thomas Stuttaford |first2=Suzi |last2=Godson |date=October 6, 2007 |title=Taking the first steps |url=http://www.timesonline.co.uk/tol/life_and_style/health/expert_advice/article2595671.ece |work=The Times}}{{dead link|date=September 2024|bot=medic}}{{cbignore|bot=medic}} Moreover, MRI during coitus indicate that the internal part of the clitoris{{cite journal | last1 = O'Connell | first1 = H.E. | last2 = Hutson | first2 = J.M. | last3 = Anderson | first3 = C.R. | last4 = Plenter | first4 = R.J. | year = 1998 | title = Anatomical relationship between urethra and clitoris | journal = The Journal of Urology | volume = 159 | issue = 6| pages = 1892–1897 | doi=10.1016/s0022-5347(01)63188-4 | pmid=9598482}}{{cite journal | last1 = O'Connell | first1 = H.E. | last2 = DeLancey | first2 = J.O. | year = 2005 | title = Clitoral anatomy in nulliparous, healthy, premenopausal volunteers using unenhanced magnetic resonance imaging | journal = The Journal of Urology | volume = 173 | issue = 6| pages = 2060–2063 | doi=10.1097/01.ju.0000158446.21396.c0| pmc = 1283096 | pmid=15879834}} is stimulated by penile-vaginal movements.{{cite journal | last1 = Foldes | first1 = P. | last2 = Buisson | first2 = O. | year = 2009 | title = The clitoral complex: a dynamic sonographic study | journal = J. Sex. Med. | volume = 6 | issue = 5| pages = 1223–1231 | doi=10.1111/j.1743-6109.2009.01231.x | pmid=19453931| s2cid = 5096396 }} These studies highlight the role of the clitoris and indicate that what is termed the G-spot may only exist because the highly innervated clitoris is pulled closely to the anterior wall of the vagina when the woman is sexually aroused and during vaginal penetration.{{cite journal | last1 = Buisson | first1 = O. | last2 = Jannini | first2 = E.A. | year = 2013 | title = Pilot echographic study of the differences in clitoral involvement following clitoral or vaginal sexual stimulation | journal = J. Sex. Med. | volume = 10 | issue = 11| pages = 2734–2740 | doi=10.1111/jsm.12279| pmid = 23937167 }}