Sexual Anatomy 101

Navigating our connection with our sexual anatomy may present a nuanced journey. While it has the potential to unlock profound pleasure, for some individuals, it becomes a source of considerable shame and distress. Acquiring knowledge about our anatomy serves as an empowering tool, allowing us to understand our bodies better and give us the confidence we need to embrace our sexual anatomy .

Why do we say ‘AMAB’ & ‘AFAB’?

Assigned sex is a label you’re given at birth based on medical factors, including hormones, chromosomes and genitals.

Some people call the sex we’re assigned at birth “biological sex.” However, this term doesn’t fully capture the complex biological, anatomical, and chromosomal variations. Having only two options (biological male or biological female) might not describe what’s going on inside a person’s body.

Using ‘Assigned sex’ acknowledges that someone else made the decision for that person and it may not align with how they feel & identify or what is going on in their body. Learn more about gender and sex here.

(All images hand-drawn by me - full ownership and rights to use)

Vulva Not Vagina

Often, when people discuss the vagina, they are actually referring to the vulva.

vulva diagram anatomical

The vulva is everything on the outside of the AFAB reproductive system, encompassing the outer and inner lips (labia majora and minora), clitoral hood, clitoris, vestibular bulbs, vaginal vestibule, and the vaginal opening. Remarkably diverse, vulvas exhibit variations in colour, shape, and size. Even one side may differ from the other. Societal expectations, fueled in part by the porn industry, have constructed a predefined notion of what a vulva "should" resemble. In reality, they are diverse, each unique - like a snowflake! 

What is the Vagina?

The vagina serves as the muscular passage situated between our vulva and cervix. Comprised of vaginal tissue, it features an opening just below the urethral opening. This orifice is not only where menstrual blood exits and daily discharge occurs but also where various objects, including fingers, sex toys, penises, and menstruation products, may be inserted. 

Contrary to popular belief many people with vaginas cannot orgasm from penetration alone and most need clitoral stimulation.

What is the Labia?

The labia majora, commonly referred to as the 'outer lips,' consists of thick skin areas typically covered with pubic hair, extending from the mons pubis to the anus. Comprising sweat glands and primarily composed of muscle tissue, they play a crucial role in the AFAB anatomy.

In contrast, the labia minora, known as the 'inner lips,' extend from the clitoris to below the vaginal opening. During sexual arousal, both labia may swell in response. Labia come in varying lengths, with one often longer than the other. 

The colour spectrum ranges from very pink to dark brown, and regardless of shape, colour, or size, all labia are considered normal. Between the labia minora lies the vaginal vestibule, encompassing the skin surrounding the urethral and vaginal openings.

What are the Bartholin Glands?

The Bartholin's glands play a crucial role in generating fluid that aids in lubricating the vagina. While this typically occurs during sexual arousal, it can also happen without sexual arousal.

The importance of the AFAB Pelvic Floor

Extending across the base of the pelvis, the pelvic floor muscles provide support to the pelvic organs, including the bladder and bowel in both genders and additionally, the uterus (womb) in women. Weakness in these muscles can result in issues related to bladder and bowel control. 

The pelvic floor muscles play a crucial role in sexual function, facilitating relaxation and contraction that contributes to enjoyable and pleasurable experiences. 

The Clitoris?

clitoris diagram anatomical

The clitoris stands as the epicenter of pleasure, previously believed to house around 8,000 nerve fibers but potentially exceeding 10,000, as suggested by @queersurgeon. 

Externally, the clitoris goes by various names such as the pea, the bean, button, and clit, with the scientific term being the clitoral glans. Positioned at the top of the vulva, this visible part is partially covered by the clitoral hood, a protective skin fold. Similar to the labia, both the clitoris and its hood exhibit diverse sizes, all within the spectrum of normal.

The internal aspects of the clitoris remain mostly concealed, comprising the body, crura, and vestibular bulb. The clitoral body connects to the glans, subsequently dividing into the vestibular bulb and crura. The erectile tissue in the vestibular bulb and crura swells during sexual arousal, leading to vaginal lubrication. It's essential to note that lubrication doesn't always indicate arousal, and its absence doesn't negate arousal.

The clitoris undergoes continuous growth throughout life, potentially reaching two and a half times its size by the age of 90. 

The Clitoris and Penis are very similar

We all start the same, the diagram below highlights just how similar we are.

Essentially, 'male' and 'female' sex embryos start with the same parts and develop into their respective sex organs later in the womb.

clitoris and penis diagram anatomical similar

The sexes are indistinguishable until about 9 weeks of development. At a certain point in development hormones called “androgens” stimulate the development of male or female sexual (gender is different) characteristics.

As the fetus develops, the glans will either become the head of the penis or the clitoris, and the labioscrotal swellings will either become the outer labia (or lips) of the vulva or they will fuse to become the scrotum (which is why some scrotums have a little line down the middle).

In certain cases, an infant will be born with ambiguous genitalia. For example: an enlarged clitoris and testicles, or a vaginal opening and a penis. People born with these characteristics are known as intersex.

The penis and clitoris are so similar they can both be turned into each other during gender affirmation surgery!

AMAB = Assigned Male at Birth

The Penis

The primary location of the AMAB reproductive system is within the pelvis, with certain tissues situated outside in the scrotum to maintain a cooler environment. The male reproductive system comprises seven main parts: the penis, the testes and epididymis, the scrotum, the spermatic cord, the prostate gland and the seminal vesicles.

The penis itself has 3 cylinders of spongy erectile tissue (see below), two corpus cavernosum & the corpus spongiosum (the urethra lives in this). They all swell during arousal and allow ejaculation to occur.

penis diagram cross section anatomical

Penis Size

In society, the penis is often talked about, drawn and judged based on its size thanks to unrealistic expectations often from lack of sex education and turning to porn to learn and see ‘real’ bodies.

The average SPL (stretched penile length) is 4.94 inches & for a penis to class as a ‘micropenis’ (which affects less than 5% of men it would need to be under 2.95 inches. Only 1% of those with a penis have one that is over 7.87 inches - all of our bodies are different and you can have amazing sexual encounters regardless of size.

The Scrotum & Testes

The testes are about the size of a ping pong ball and are responsible for making testosterone and sperm. The Scrotum contains and holds the testes outside of the body to keep them the sperm at an optimum temperature.

The Anus & Prostate

The Anus (regardless of sex) has a rich supply of blood and nerves and does not relax or self-lubricate during arousal, making it’s super important to use lubricant and condoms to reduce the risk of STI transmission with skin that is easily tearable.

The prostate is a walnut-sized gland that is situated beneath the bladder of people with penises. The prostate gland encircles the upper part of the urethra, the tube responsible for draining urine from the bladder. The main role of the prostate is to generate the fluid essential for nourishing and transporting sperm, known as seminal fluid. Some AMAB people enjoy the stimulation of the prostate through the anus with a finger or toy as it can product stronger/longer orgasms.

penis diagram anatomical

The Epididymus & Vas Deferens

The epididymus is a long, coil tube that rests on the back of the testicles. It transports and stores sperm. The vas deferens is a long, muscular tube that joins the urethra and provides contractions to force the sperm out the end of the penis during sex or masturbation. This also stops the sperm going into the bladder, somethng AMAB people can suffer from in their later years.

The Ejaculatory Ducts

The ejaculatory ducts are formed by the fusion of the vad deferens and the seminal vesicle which empty into the urethra.

male amab diagram sexual reproductive anatomy

The Importance of the AMAB Pelvic Floor

The pelvic floor muscles for people with penises play a vital role in supporting the bladder and bowel, and they also influence sexual function and the explusion of seminal fluid. Much like those with Vulvas, engaging in Kegel exercises is a beneficial way to strengthen these muscles.

The sex education you never got.

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