The urethra is a duct that moves urine from the bladder to the outside of the body during urination. The urethral sphincter, a muscular structure, keeps the urethra closed, holding urine in the bladder until voiding occurs. Because of its link to reproductive structures, the male urethra differs significantly from the female's. The male urethra, about 18 to 20 cm long, runs the length of the penis. Seminal ducts from the testes enter the urethra, making it a pathway for semen and urine. It comprises the prostatic, membranous, and spongy sections. The female urethra, only about 4 cm long, is embedded in the vaginal wall.

Where is the urethra located in the human body?

The urethra is a duct that allows urine to pass from the bladder to the outside of the body. The location and length of the urethra differ between males and females. The male urethra, about 18 to 20 cm long, starts at the bladder, goes through the prostate gland, and runs along the penis. It is divided into the prostatic, membranous, and spongy urethra. The female urethra is much shorter, about 4 cm long, and is embedded in the vaginal wall, with its opening situated between the labia. The muscular coat of both the male and female urethra is continuous with the musculature of the bladder.

What is the main function of the urethra?

The primary function of the urethra is to transport urine from the bladder to the outside of the body during urination. The urethral sphincter, a muscular structure, keeps the urethra closed, holding urine in the bladder until voiding occurs. In males, the urethra also serves as a pathway for semen. The male urethra is about 18 to 20 cm long, passing through the prostate gland, where the seminal ducts enter. The female urethra is shorter, around 4 cm long, and is embedded in the vaginal wall.

How is the urethra different in males and females?

The urethra serves to transport urine from the bladder to the outside of the body. Key differences exist between males and females because of the urethra's anatomical link to reproductive structures. The male urethra is approximately 18 to 20 cm long and runs the length of the penis. It functions as a passage for both urine and semen. The male urethra consists of the prostatic, membranous, and spongy sections. In contrast, the female urethra is about 4 cm long and is embedded in the vaginal wall. The female urethra's opening sits between the labia. The female urethra is shorter and more distensible than in males, and it solely transports urine. Females are also more susceptible to UTIs due to their shorter urethra.

What structures or tissues surround the urethra?

The urethra is surrounded by different structures and tissues depending on whether it is in a male or a female. In males, the urethra is approximately 18 to 20 cm long and has three sections: the prostatic, membranous, and spongy urethra. The prostate gland surrounds the prostatic urethra, and seminal ducts from the testes enter here. The membranous urethra is within the urethral sphincter, and the spongy urethra is within the penis. The male urethra has a mucous membrane supported by a submucous layer and an incomplete muscular coat. In females, the urethra is about 4 cm long and is embedded within the vaginal wall. The female urethra also has mucous, submucous, and muscular coats. Fibers from the outer circular layers of the muscular coat intermix with those in the anterior wall of the vagina.

How can problems with the urethra affect urination or health?

Problems with the urethra can significantly impact urination and overall health. Urethritis, an inflammation of the urethra often caused by infections like chlamydia or gonorrhea , can lead to painful and frequent urination. Scarring from inflammation may narrow the urethra, causing difficulty in passing urine and potentially leading to severe infections and kidney failure. Additionally, obstructions from stones or congenital issues like hypospadias can disrupt normal urinary function. Infections in the urinary tract can also cause urethral problems, with symptoms including pain, bleeding, and discharge. Trauma to the urethra can result in swelling, bleeding, and an inability to urinate, requiring urgent surgical intervention.

urethra

Introduction References & Edit History Related Topics

Images

Diagram of the human excretory system showing the kidneys, ureters, bladder, and urethra, with their anatomical positions highlighted inside a human silhouette.

Cross-sectional anatomical illustration of the male pelvis showing the urinary bladder, urethra, and surrounding structures. The image labels key parts including the bladder, neck of bladder, prostate, prostatic urethra, bulbospongiosus muscle, and associated muscles, glands, and fascia.

Medical illustration of the male reproductive system in cross-section, showing labeled anatomical structures such as the penis, testis, scrotum, prostate, urethra, seminal vesicle, and associated ducts and glands.

Medical illustration of a sagittal section of the human male reproductive system, showing the prostate gland, seminal vesicles, urinary bladder, urethra, rectum, and associated ducts and glands, each labeled for anatomical reference.

Diagram of the female renal system showing kidneys, adrenal glands, and urinary tract organs in their anatomical positions, with labels for major structures including blood vessels, bladder, and uterus.

Quick Facts

Related Topics:: renal system; urethritis; urethral gland; renal system

See all related content

urethra

anatomy

Written and fact-checked by

Britannica Editors

Last updated

Oct. 14, 2026 •History

Top Questions

What is the urethra?
The urethra is a duct that moves urine from the bladder to the outside of the body during urination. The urethral sphincter, a muscular structure, keeps the urethra closed, holding urine in the bladder until voiding occurs.

Because of its link to reproductive structures, the male urethra differs significantly from the female's. The male urethra, about 18 to 20 cm long, runs the length of the penis. Seminal ducts from the testes enter the urethra, making it a pathway for semen and urine. It comprises the prostatic, membranous, and spongy sections. The female urethra, only about 4 cm long, is embedded in the vaginal wall.
2 Britannica Sources
1. renal system: General description
2. urethra
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Where is the urethra located in the human body?
The urethra is a duct that allows urine to pass from the bladder to the outside of the body. The location and length of the urethra differ between males and females. The male urethra, about 18 to 20 cm long, starts at the bladder, goes through the prostate gland, and runs along the penis. It is divided into the prostatic, membranous, and spongy urethra. The female urethra is much shorter, about 4 cm long, and is embedded in the vaginal wall, with its opening situated between the labia. The muscular coat of both the male and female urethra is continuous with the musculature of the bladder.
2 Britannica Sources
1. renal system: Structure of urethral wall
2. urethra
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What is the main function of the urethra?
The primary function of the urethra is to transport urine from the bladder to the outside of the body during urination. The urethral sphincter, a muscular structure, keeps the urethra closed, holding urine in the bladder until voiding occurs.

In males, the urethra also serves as a pathway for semen. The male urethra is about 18 to 20 cm long, passing through the prostate gland, where the seminal ducts enter. The female urethra is shorter, around 4 cm long, and is embedded in the vaginal wall.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How is the urethra different in males and females?
The urethra serves to transport urine from the bladder to the outside of the body. Key differences exist between males and females because of the urethra's anatomical link to reproductive structures.

The male urethra is approximately 18 to 20 cm long and runs the length of the penis. It functions as a passage for both urine and semen. The male urethra consists of the prostatic, membranous, and spongy sections.

In contrast, the female urethra is about 4 cm long and is embedded in the vaginal wall. The female urethra's opening sits between the labia. The female urethra is shorter and more distensible than in males, and it solely transports urine. Females are also more susceptible to UTIs due to their shorter urethra.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What structures or tissues surround the urethra?
The urethra is surrounded by different structures and tissues depending on whether it is in a male or a female.

In males, the urethra is approximately 18 to 20 cm long and has three sections: the prostatic, membranous, and spongy urethra. The prostate gland surrounds the prostatic urethra, and seminal ducts from the testes enter here. The membranous urethra is within the urethral sphincter, and the spongy urethra is within the penis. The male urethra has a mucous membrane supported by a submucous layer and an incomplete muscular coat.

In females, the urethra is about 4 cm long and is embedded within the vaginal wall. The female urethra also has mucous, submucous, and muscular coats. Fibers from the outer circular layers of the muscular coat intermix with those in the anterior wall of the vagina.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How can problems with the urethra affect urination or health?
Problems with the urethra can significantly impact urination and overall health. Urethritis, an inflammation of the urethra often caused by infections like chlamydia or gonorrhea, can lead to painful and frequent urination. Scarring from inflammation may narrow the urethra, causing difficulty in passing urine and potentially leading to severe infections and kidney failure.

Additionally, obstructions from stones or congenital issues like hypospadias can disrupt normal urinary function. Infections in the urinary tract can also cause urethral problems, with symptoms including pain, bleeding, and discharge. Trauma to the urethra can result in swelling, bleeding, and an inability to urinate, requiring urgent surgical intervention.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

urethra, duct that transmits urine from the bladder to the exterior of the body during urination. The urethra is held closed by the urethral sphincter, a muscular structure that helps keep urine in the bladder until voiding can occur.

Because the urethra is anatomically linked with the reproductive structures, its characteristics in males are quite different from those in females. The male’s urethra is about 18 to 20 cm (7 to 8 inches) long and passes along the length of the penis before emptying. At its emergence from the bladder, the urethra passes through the prostate gland, and seminal ducts from the testes enter the urethra at each side, making it the pathway for the transmission of semen as well as for the discharge of urine. The male urethra can be divided into three sections: the prostatic urethra (the uppermost segment within the prostate), the membranous urethra (the segment within the urethral sphincter), and the spongy urethra (the lowermost and longest section within the penis). Additional sections may be recognized, including the preprostatic urethra (at the neck of the bladder) and the fossa navicularis, pendulous urethra, and bulbous urethra, all subdivisions of the spongy urethra. In addition, the male urethra may be described in terms of a posterior region (prostatic and membranous urethras) and an anterior region (spongy urethra).

The female urethra is embedded within the vaginal wall, and its opening is situated between the labia. The female urethra is much shorter than that of the male, being only 4 cm (1.5 inches) long. It begins at the bladder neck and opens to the outside just after passing through the urethral sphincter.

Male muscle, man flexing arm, bicep curl.

Britannica Quiz

Facts You Should Know: The Human Body Quiz

The urethra can be affected by any of various conditions. In hypospadias, a congenital disorder, the urethra opens on the underside of the penis. Both the male and female urethra are subject to urethritis, an inflammatory condition often brought on by infection. Urethral stricture, or narrowing of the urethra, also can be caused by developmental conditions as well as by inflammation, infection, or injury. Urethral cancer is a rare condition, more common in women than men; risk is influenced by a history of bladder cancer, as well as by conditions associated with chronic inflammation of the urethra (e.g., frequent urinary tract infection). Common symptoms of inflammation or infection include difficulty urinating, frequent urination, dysuria (pain with urination), and bleeding or discharge from the urethral opening. An obscure condition known as urethral syndrome may be diagnosed when symptoms indicative of urethral infection are present but demonstrable infection is absent.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Rick Livingston.

urethra

Thank you for signing up!