The penis is the male copulatory organ. The term penis typically refers to the root, body, and glans of the genitals. The rest of the male sexual anatomy includes other external parts such as the scrotum, and internal parts such as the testicles.
The penis contains soft, spongy tissue as well as muscles, fibrous tissue, veins, arteries, and the urethra. These allow the penis to perform its functions.
The penis has three parts:
Root: This is the part of the penis attached to the body and is not visible externally. It contains three erectile tissues, which include two crura and the bulb of the penis, and two muscles called the ischiocavernosus and bulbospongiosus. The urethra connects to the bladder and passes through all parts of the penis.
Body: The body, or shaft, is the free part of the penis between the root and glans. It contains three cylinders of erectile tissue, which include two corpora cavernosa and the corpus spongiosum.
Glans: This is the most distal, or end, part of the penis. It gets its shape from the bulbous expansion of the corpus spongiosum. The glans also features the urethral opening, which is where the urethra ends, allowing a person to expel urine and semen.
The erectile tissues
These are the tissues that fill with blood during arousal, which allow a person to have an erection. In the root, this starts with the left and right crura and the bulb of the penis, which is in the midline of the penile root.
The left and right crura continue into the body of the penis and form the two corpora cavernosa. The bulb continues into the body and forms the corpus spongiosum. The urethra runs through the corpus spongiosum, which prevents it closing during an erection. The corpus spongiosum then expands to form the glans of the penis.
The bulbospongiosus muscle is associated with the bulb of the penis. It contracts to help empty the urethra of any residual semen and urine. The ischiocavernosus muscle surrounds the left and right crura. It contracts to force blood in the crura into the corpora cavernosa which helps a person to maintain an erection.
Each erectile tissue has fascial coverings, or bands of connective tissue, which surround and support them. This includes the deep fascia of the penis, or Buck’s fascia, and the tunica albuginea. These coverings help protect the penis and help maintain an erection by preventing blood from leaving the erectile tissues.
The suspensory and fundiform ligaments support the root of the penis and attach to the surrounding structures. The suspensory ligament holds the penis close to the pubic bone and supports it when erect. The fundiform ligament also supports the penis, surrounding it like a sling.
Skin covers the entire body of the penis. People may also have a retractable layer of skin that covers the glans. People may refer to this as the prepuce, or foreskin. The foreskin connects to the surface of the glans by a fold of skin known as the frenulum.
The two main functions of the penis include sexual intercourse and micturition (urination).
When a person experiences arousal, the penis fills with blood, causing an erection. As such, erectile function is closely related to cardiovascular health.
The rigidity of the erection enables a person to penetrate a partner and have sex. Following sexual activity or manual stimulation, a person can then ejaculate. After ejaculation or loss of arousal, the penis can return to a flaccid state.
The penis also plays an important urinary role. The penis contains the urethra, which allows passage of urine from the bladder to the urethral opening, enabling a person to expel urine from the body.
Types of penises
Just like any other body part, the penis can vary greatly from person to person. For penises, people typically notice differences in measurements and appearance.
Penises come in different lengths and girths, and this changes when flaccid or erect. Some people may measure the base-to-head ratio. There is no single size that is better than others, and people will have their own personal preference. There are more important factors for sexual compatibility than just penis size.
When erect, some penises may be straight, while others may have a bend. Penile curvature is common, rarely painful, and does not usually make penetrative sex more difficult. In fact, in some cases, penile curvature may be more pleasurable for the receiving partner.
Some people may or may not have a foreskin on their penis. Some individuals may have the foreskin surgically removed in a procedure called circumcision.
List of conditions
There are many conditions that can affect the penis. These may include:
Erectile dysfunction: This typically refers to when a person has difficulty getting or keeping a firm enough erection to have sex.
Priapism: This is when blood becomes trapped in the penis and can cause a prolonged and painful erection that can result in permanent tissue damage.
Chordee: This is a condition where bands of tissue pull on the penis, giving it a bent appearance.
Peyronie’s disease: This condition occurs when scar tissue forms under the penis’ skin and causes an abnormal curvature of the penis.
Urethritis: Inflammation and swelling of the urethra can result in difficulty or pain when urinating.
Micropenis: This refers to an abnormally small penis, typically due to hormonal or genetic issues.
Buried penis: This is a medical condition where excess skin and fat cover the penis, making it less visible.
Penile cancer: This is a rare type of cancer that develops on or in the penis.