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Penis Anatomy

As a sexual, reproductive and micturition organ, the human penis has a more complex structure than one could imagine. Having the basic knowledge with regards to penis anatomy is vital for maintaining it healthy and functional.

From the outside, the penis appears to consist from a shaft ending with a foreskin and the foreskin opening. On the inside, there are three different tissue columns: corpus spongiosum, representing the main part of the penis, and two corpora cavernosa, which frame the corpus on sides. Corpus spongiosum ends in a voluminous and bulbous shaped tissue known as the glans, whose role is to support the foreskin – a loose skin fold covering the glans and attached with a frenulum.

For a better understanding of everything involving the anatomy of the male organ, we will present below two explicit photos taken with the courtesy of PenisHealth.com, together with detailed explanations.

This first frame is an overview of the penis, with its corpora cavernosa chambers, the scrotum, the urethra and the prostate gland. It is obvious how the organ is made from two main parts, the corpus and the root, with the root being attached to the pubic bone. All attempts of increasing penis size are focusing on either increasing the volume of the spongy tissue or allowing the part of the penis attached to the pubic bone to expand towards outside by surgically loosening its ligaments.

An erection represents the biological process of sexual arousal, manifesting through the stiffening followed by the rising of the male organ. The erection is the manifestation of the blood flow coming through the dilated arteries into the spongy tissues of the penis, causing it to increase its volume. With an increased volume, the veins will automatically be constricted, making for the blood flow that leaves the penis to be considerably lower than the one that enters. A strong erection will be achieved when these two amounts of blood are equal and kept equal for a particular amount of time.

The penis consisting, on a primary level, of sponge tissue, blood vessels and nerves, the arousal is detected and transmitted towards and from the brain through nervous signals while the blood vessels are told to relax or constrict. On a deeper level however, each part of the male reproductive system plays its own role and below presented will be detailed information on this chapter:


The corona – the base of the penis glans, round shaped and a little extended outwards

Together with the glans it stays covered by the foreskin and it only erects with sexual arousal. Its color can be different from the one of the penis head, regularly darker. The corona can be affected by Hirsuties papillaris genitalis, a harmless yet quite common medical condition known in usual terms as Pearly penile papules.


The corpora cavernosa – a pair of erectile tissues with a spongy construction that fills in with blood during an erection and increases the size of the penis.

They are disposed along the penis length, close to the shaft, beginning with the pubic bone and ending with the head of the organ where the two of them join. Many male enhancement supplements, natural or synthetic, use substances that enhance the release of nitric oxide which is known to help these two chambers relax even more, take in extra blood and support a firmer and harder erection.


The cowper’s glands – pair of glands located underneath the prostate gland, on both sides of the urethra.

Their role is to secrete the lubricating mucus into the urethra, also known as pre-ejaculate fluid, a clear mucus very similar with semen as composition. Their secretion neutralizes the acid environment from the urethra, creating the conditions for sperm to be expelled, and removes all foreign materials that may harden the ejaculation.


The ejaculatory ducts – the path through the seminal glands that semen takes during ejaculation.

There are two of them, each one consisting from the reunion of the seminal vesicle’s duct and the vas deferens. Entering into the prostate, they finally open in the urethra. They interfere in the emission stage of the ejaculation, when the prostate gland together with the seminal vesicles and, of course, the vas deferens start contracting and making the semen to travel from one to another up to the cowper’s glands which already released the pre-ejaculate fluid.


The epididymis – the place where the sperm matures and where it is kept prior to nocturnal emissions or intercourse ejaculations

It can store sperm for two to three months, at which stage the sperms are not able to fertilize because of poor motility, which they improve throughout their sedimentation in here. Epididymis can often cause pain in testes on a regular base or prior to a vasectomy. In this last circumstance it must also be surgically removed in order to stop the pain.


The foreskin / prepuce – a roll of skin that covers the head of the penis in uncircumcised men.

Double layered and retractable, the foreskin is made from a mucous membrane on the inside, which protects both the glans of the penis and the urinary meatus. The smooth and tinny muscle fibers normally keep it near the glans while increasing its elasticity. The foreskin is connected to the glans through the frenulum.

It can be surgically removed with a circumcision procedure for reasons that vary from religious requirements and personal preferences to the real need of treating particular medical conditions.


The frenulum/frenum – a thin strip of flesh on the underside of the penis that connects the shaft to the head

It helps with the contraction of the prepuce as the arousal reduces intensity and the glans need to be covered again. It has been described as highly erogenous because of its sensitivity on soft and light touches and it was proven to make particular men ejaculate after repeated stimulation on it.

Some men suffer from a condition known as frenulum breve, which consists of a shorter frenulum, and manifesting through a limitation of the prepuce’s movements. Because of its very fragile structure it can tear during intercourse and once the frenular artery severed, major bleeding will manifest.


The glans – the head of the penis, normally covered by the prepuce at uncircumcised men. At its tip there is the opening of the urethra, known as meatus.

The glans is highly sensitive, just like the corona sitting underneath it. Up to 11% of all men experience the condition called balanitis, which is a very painful irritation or upsetting infection. Men suffering from diabetes are even more likely to have it.

The prostate gland – exocrine gland secreting a white or milky fluid slightly acid representing up to 30% of the total semen volume when combined with the fluid of the seminal vesicle and the spermatozoa.

It also squeezes shut the urethral duct to the bladder, thus preventing urine from mixing with the semen and disturbing the pH balance required by sperm. The inflammation of this gland is called prostatitis and can manifest in four different forms, every single one with individual triggers and outcomes.


The scrotum – the extension of perineum – skin layer making the link between the penis and the anus – it is a protuberance of muscles and skin, with two chambers, and which contains the two testicles separated through a so-called septum.

It’s main purpose is to maintain the testes’ temperature lower with a few degrees than the body’s temperature in order to maintain the sperm count on the right level. The testes are moves closer or further from the body depending on the temperature from the environment, always maintaining that equilibrium.


The seminal vesicles – pair of tubular glands from inside the pelvis

They produce semen, a fluid that activates and protects the sperm after it has left the penis during ejaculation, so that to increase the life of the sperms inside the vagina and their odds of reaching the ovule and fertilizing it.


The smegma – a substance with the texture of cheese secreted by glands on each side of the frenulum in uncircumcised men

Combining exfoliated skin cells with skin oils and moisture, smegma maintains the glans moisturized and acts like a lubricant, facilitating the penetration during intercourse. It contains 13.3% proteins and 26.6% fats.


The testes/testicles – male sexual glands responsible with producing sperm and testosterone

Within each testis is a kilometer of ducts called the seminiferous tubules, the organs that generate sperm. They produce, individually, nearly 150 million sperm at every 24 hours.

Kept inside the scrotum, the two testicles are very sensitive to all sorts of injuries and every time when pain is caused in that region, it will intensify and travel up to the abdomen through a major nerve. Testicular torsion and rupture are two medical emergencies.


The Urethra – a tube connecting the urinary bladder with the genitals

It travels the penis shaft and carries both semen and urine. It has a sphincter that allows voluntary control with the urination. Its approximately 8 inches length consist of four main parts: the pre-prostatic urethra – the intramural region; the prostatic urethra – the part that crosses the prostate and opens with the ejaculatur ducts, the prostatic ducts and the prostatic utricle; the membranous urethra – the part that crosses the urethral sphincter; and the spongy urethra – the part that travels through the penis and opens on its ventral side with the meatus.

Infections, kidney stones and cancer are the most threatening conditions that a man can experience.


The urethra meatus – opening at the tip of the penis to allow the passage of both urine and semen

The urinary meatus opens at the junction of frenular delta and the glans and goes along with the ventral part of the glans in a tubular shape. One of the most common conditions that can affect this orifice is the urethral blockage, caused by bladder or kidney stones. Additionally, in rare cases, one can experience a birth defect manifesting through an abnormal placement of the meatus anywhere along the urethral groove.


The vas deferens – ducts leading from the epididymis to the seminal vesicles

They have a muscular structure, a length of approximately 30 centimeters and reflexively contract during ejaculation, which helps the sperm to move forward to the urethra. These are the ducts that are cut during the procedure known as vasectomy.