Penis: Anatomy, Function, Disorders, and Diagnosis

The penis is a complex external organ in males used to urinate and for sex and replica. It consists of respective parts, including the shaft, head, and prepuce .

This article describes the anatomy and function of the penis adenine well as conditions that can affect the serve or appearance of the penis at birth or former in life .


The penis is located at the front of the body at the base of the pelvis. The scrotum, containing the testicles, lies below the penis .

The penis consists of respective major structures :

  • Glans: The glans, or head of the penis, is the sensitive structure at the end of the corpus (shaft).
  • Urethra: The urethra is a tube that runs from the bladder to the head of the penis, It is used for urination. It also crosses through the prostate gland where an opening, called the ejaculatory duct, receives sperm and fluid that make up semen.
  • Meatus: The meatus is the opening at the tip of the glans through which urine or semen exits the body.
  • Prepuce: The prepuce, or foreskin, is a loose fold of skin that covers the head of the penis. The removal of the foreskin is referred to as circumcision.
  • Corpus cavernosa: The corpus cavernosa are two columns of spongy tissue that run along the interior shaft of the penis. When filled with blood, the tissues stiffen, causing an erection.
  • Corpus spongiosum: The corpus spongiosum is the third column of tissue that prevents the urethra from closing during an erection.

The penis is well supplied by blood vessels. The shaft, which contains the urethra and three column of erectile weave, is wrapped in a isthmus of connection weave called the fascia and covered with skin. The base of the penis is supported by connection tissues, called suspensory ligaments, that hold the penis close to the pelvic bone .

The average soft ( “ soft ” ) duration of a penis is 3.5 inches. The average length of an tumid penis is 6 inches with an modal circumference of 5 inches .


The penis is made up of the corpus ( cock ), glans ( lead ), and prepuce ( prepuce ). The urethra is a tube through which urine or semen exits the body. The spongy column of weave within the rotating shaft can fill with rake and cause an erection .


The primary functions of the penis are urinary and intimate. The sexual function of the penis can be far broken down into two stages : erection and ejaculation .


micturition is the exhaust of urine from the body. This occurs when urine passes from the bladder through the urethra to the meatus. The urine is pushed out of the body by the contraction of the detrusor muscleman in the wall of the bladder .

At the root of the penis is the external sphincter muscle, which males can control to hold in or release urine .


An erecting is the stiffening of the penis caused by sexual arousal and/or physical stimulation. It is besides normal for erections to occur during sleep and upon waking. An erecting occurs when there is an increased flow of blood into the corpus cavernosa and corpus spongiosum .

During an erection, arteries supplying the erectile tissues will dilate ( widen ), causing the penis to engorge ( satiate ) with blood. The engorgement compresses the veins through which blood normally exits the penis. This “ traps ” the rake and helps sustain the erection .


ejaculation is the discharge of semen from the body. It is normally accompanied by a sexual response called an orgasm .

ejaculation involves a series of coincident, involuntary muscle contractions :

  • First, a tube called the vas deferens contracts, propelling sperm from the testicles to the ejaculatory duct.
  • At the same time, the prostate gland and seminal vesicles contract, adding fluids that make up most of the volume of semen.
  • At the same time, rapid contraction of muscles at the base of the penis, called periurethral muscles, propel semen out of the penis.


The primary functions of the penis are micturition, erection, and ejaculation. Each involves a complex series of involuntary and voluntary processes.

congenital Abnormalities

There are respective congenital conditions that can cause a penis to be abnormally formed. congenital disorders are those that are present at parturition and caused when something interferes with the normal development of an unborn baby .

congenital penis abnormalities are normally caused by an imbalance of hormones that influence penis development .

Hypospadias and Epispadias

Hypospadias is a condition where the open of the urethra is on the bottom of the penis quite than at the topple. It is one of the most common congenital abnormalities in males. Epispadias is a similar stipulate in which the urethra opens on the top side of the penis .

surgery is by and large recommended to correct hypospadias either during infancy or early childhood. however, there are risks of long-run complications, including difficulty make and an increased gamble of urinary nerve pathway infections .


Chordee is an abnormal bend of the penis at the time of give birth. It is more coarse in males with hypospadias but can besides occur on its own. In adolescent and adult males, chordee is most noticeable during an erection.

Chordee vs. Peyronie’s Disease

Chordee should not be confused with Peyronie ‘s disease. Peyronie ‘s is a condition that develops in adult males that causes an abnormal bend of the penis .


Micropenis is an abnormally minor penis. It is defined as a stretch penis that is at least 2.5 times smaller than what would be expected at that stage of a male ‘s exploitation. In adults, this would be stretched penis of less than 2.75 inches .

Micropenis affects 1.5 out of 10,000 male children in the United States. It is thought the be caused by abnormally low production of male hormones, called androgens, during pregnancy.


The congenital absence of a penis, called aphalia, is an extremely rare condition, affecting one of every 30 million births. It normally occurs with other congenital abnormalities affecting the affection or digestive nerve pathway. The lawsuit of aphalia is stranger. then far, fewer than 100 cases have been reported.


congenital penis abnormalities are rare but can cause the abnormal placement of the urethra ( hypospadias, epispadias ), the abnormal curve of the beam ( chordee ), an abnormally little penis ( micropenis ), or no penis at all ( aphalia ).

dysfunction and Diseases in Later Life

There are a number of aesculapian conditions that can affect the serve or appearance of the penis in subsequently life. These may affect the glans, prepuce, urethra, or erectile tissues .

Erectile dysfunction

Erectile dysfunction occurs when a person can not get or maintain an erection sufficient for intimate sexual intercourse. Erectile dysfunction may be caused by medical reasons, including medications or heart disease. It may besides be the solution of stress, anxiety, or relationship problems .

Peyronie ‘s Disease

Peyronie ‘s disease ( PD ) is an abnormal swerve of the penis that occurs in late biography. Studies suggest that around 0.5 % of adult males will experience PD at some time in their life. The risk increases as you get older .

Peyronie ‘s disease is chiefly the result of a anterior injury to the penis during sex. With that said, PD is ill silent and may occur for no know cause. If the symptoms of PD are austere, they can cause erectile dysfunction .

penile fracture

A penile fracture occurs when the slurred membrane surrounding the corpus cavernosa, known as the tunic albuginea, ruptures during vigorous sex. The tunic albuginea is supplied with a rich network of blood vessels that can cause shed blood and hard pain when ruptured. The scar weave that results from a penile fracture may lead to Peyronie ‘s disease .

phimosis and Paraphimosis

phimosis is a condition where the prepuce is besides besotted to be pulled back over the oral sex of the penis. Phimosis is normal in babies and toddlers, but, in older children, it may be the leave of a skin condition that causes scarring. It is not normally a problem unless it causes symptoms .

Paraphimosis occurs in uncircumcised males when the prepuce gets stuck in the draw in military position. It is a checkup hand brake that can lead to tissue death if not treated immediately .


priapism is an erecting that lasts more than four hours. It is not always the leave of intimate arousal and can be quite atrocious .

priapism occurs when blood becomes trapped in the penis and is ineffective to drain. If the stipulate is not treated immediately, it can lead to scarring and permanent erectile dysfunction .

priapism can occur in males of any age and is more common in those with certain blood diseases like sickle cell disease and leukemia. Certain medications can besides increase the gamble of priapism .

Penile inflammation

The penis is vulnerable to contagion. This includes sexually transmitted diseases like genital herpes or homo papillomavirus ( HPV ) that affect the skin and gonorrhea or chlamydia that can affect the urethra. These and early infections can lead to penis excitement .

inflammatory conditions affecting the penis include :

  • Balanitis: Inflammation of the head of the penis
  • Posthitis: Inflammation of the foreskin
  • Balanoposthitis: Inflammation of the head and foreskin
  • Urethritis: Inflammation or infection of the urethra
  • Urethral stricture: The abnormal narrowing of the urethra

Penile Cancer

Penile cancer is very rare. however, it can be one of the more aggressive forms of cancer. Around 95 % are caused by a type of skin cancer called squamous cellular telephone carcinoma. Penile cancer is diagnosed in fewer than one per 100,000 males each year and accounts for fewer than 1 % of all cancers in the United States.


The tests used to diagnose disorders of the penis count on the symptoms and suspected cause. You may be referred to a repair known as a urologist who specializes in disorders of the urinary nerve pathway and male generative organs .

erection Problems

The diagnosis of erectile dysfunction starts with a review of your symptoms and intimate and aesculapian history. This includes any medications you take and any emotional problems you may be experiencing .

The repair may besides order imaging studies like an sonography or magnetic plangency image ( MRI ) scan to evaluate soft tissues and blood flow. Penile imagination is often done while the penis is raise using the injection of a drug like Caverject ( alprostadil ) that causes vasodilation ( the widen of blood vessels ) .

early tests may be used to see if you get erections at night, such as nocturnal tumescence quiz .

The lapp tests and procedures are used in men with conditions like Peyronie ‘s disease that can cause erectile dysfunction .


If there is pain, ignition, and dispatch from the penis, the repair will normally screen for sexually transmitted diseases or other infections. This may include rake tests, urine tests, or a dab from inside the urethra .

If there are abnormal growths on the hide of the penis, a biopsy may be performed to get a sample of tissue for examination in the lab .

micturition Problems

Problems with micturition are normally investigated with a urinalysis that checks for abnormalities in your urine. This includes looking for pus and incendiary chemicals that can occur with a urinary tract contagion .

In older men specially, a prostate-specific antigen ( PSA ) screen may be ordered to check for an enlarge prostate gland. A digital rectal examination may besides be performed by inserting a finger into the rectum to check the size and consistency of the prostate gland .

A test called a voiding cystourethrogram may besides be ordered if you have difficulty urinate. The test, which takes images while you are urinating, can help identify if there is a blockage .


The penis is a complex harmonium used for micturition and reproduction. It contains a rich net of blood vessels that can cause the engorgement of the penis, leading to an erecting .

ejaculation is achieved by an involuntary contraction of muscles and vessels that propel semen from the body. The like tube that is used for ejaculation, called the urethra, is besides used for micturition .

different conditions can affect the appearance or function of the penis. Some are congenital and lawsuit abnormalities of the penis during fetal development. Others occur by and by in life and may be caused by injury, infections, or diseases like cancer .

An examination by a urologist may be needed to diagnose and treat disorders of the penis .

Frequently Asked Questions

  • How does the penis become erect?

    sexual foreplay or other stimulation sends messages from the brain to the nerves around the penis, causing the muscles to relax and letting rake stream into the penile arteries. This fills and stiffens spongy tissues in the penis shaft, creating an erection .
    Learn More :
    Causes of Erectile Dysfunction

  • When is penis pain a serious problem?

    many relatively child conditions can cause penile trouble. however, you should contact your healthcare provider immediately if you have pain that lasts more than four hours, have pain with other unexplained symptoms, or develop priapism ( an erection that does not go aside ) .
    Learn More :
    11 Conditions That Affect the Penis

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