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Urethra
Here we will learn the anatomy of the male and female urethrae, which conduct urine from the urinary bladder to the external environment.
The urinary bladder and urethra lie anterior to the uterus and vagina.
The perineal membrane is a layer of tough fascia that spans the urogenital triangle; the vagina and urethra pass through this membrane.
The internal urethral orifice and sphincter are located where the urinary bladder opens to the urethra. The sphincter comprises involuntary smooth muscle. Be aware that some authors consider this sphincter to be a functional sphincter, not a true anatomical sphincter.
The external urethral sphincter is in the deep perineal pouch and passes through the perineal membrane; this sphincter comprises voluntary skeletal muscle, and is what we learn to control when we're "toilet training."
The adult female urethra is 3-5 cm long and conducts urine from the urinary bladder to the vestibule of the vagina.
The vestibule of the vagnina (aka vestible of vulva) lies between folds of skin; these are the thin labia minora and thicker labia majora.
The male urethra transports both urine and semen; it is 18-20 cm in a male adult, and is subdivided into 3 sections based on surrounding tissues.
The internal urethral orifice and sphincter are located where the urinary bladder is continuous with the urethra.
The prostate gland lies just inferior to the urinary bladder; secretions from the
prostate gland contribute to seminal fluid.
The portion of the urethra that travels through the prostate gland is called the prostatic urethra.
Then, show the perineal membrane and the external urethral sphincter.
The portion of the urethra that travels through the deep perineal pouch and perineal membrane is called the membranous urethra.
We show the types of erectile tissue in the penis: the corpus spongiosum and corpus cavernosum.
The portion of the urethra that travels through the corpus spongiosum is called the spongy urethra.
The external urethral orifice is at the tip of the penis.
Notice that in both males and females, the internal urethral sphincter closes off the internal urethral orifice, but the external urethral sphincter does not close off the external urethral orifice.
Benign prostatic hyperplasia (BPH) can lead to compression of the urethra and impair urination.
Female urethra
Male Urethra
Congenital urethral abnormalities