The urethra is a tubular organ that transports urine from the urinary bladder to an opening in the perineum, discharging it outside the body.

The urethra begins with an inner or internal urethral opening (orifice) in the inferior bladder wall. It goes through the pelvic floor and perineal muscles and ends with an outer or external urethral opening (orifice or meatus). In females the opening is located 2-3 cm posterior to glans clitoris and anterior to the vaginal orifice in the vestibule of vagina, which is located between the labia minora.

The female urethra is about 1 to 1.6 inches (2.5 - 4 cm) long, while it is much longer in males - 7 to 8 inches (18 - 20 cm). The length of the urethra differs in both genders because in males it travels through the penis.

The female urethra provides only the excretion of urine, while it takes part in urination and ejaculation in males.

The female urethra is not only shorter but also wider. The diameter of the female urethra is around 0.3 - 0.4 inches (7 - 10 mm).

The female urethra adheses to the anterior vaginal wall. In contrast to the male urethra, its course is straight, and it does not have constricted or extended parts.

The basic function of the female urethra is to discharge urine that is accumulated in the bladder.

Wall of female urethra

The wall of the female urethra contains three layers:

Mucosal membrane (mucosa) - lines the organ from the inside forming longitudinal folds and contains many tiny mucous glands; the secretion of these glands protects urethra wall from urine exposure;
Submucosa - a spongy layer beneath the mucosa;
Muscular layer - surrounds the mucosa and has two sublayers - the inner longitudinal and outer circular;
Adventitia - outer fibro-elastic connective tissue layer that covers the urethra from all sides.

Urethral sphincters

The urethra has two sphincters:

Internal urethral sphincter - formed by the circular layer of smooth muscle cells around the inner urethral opening together with the muscle fibers from the urinary bladder, and its contractions are involuntary;
External urethral sphincter - located around the external urethral opening and contains striated muscle fibers that can be controlled voluntarily.

The urination process happens when both sphincters relax.

Blood supply and venous drainage

The arterial blood supply of the female urethra is provided mainly by the internal pudendal and vaginal arteries, which are branches of the internal iliac artery.

The venous drainage of the urethra in females occurs through the internal pudendal and vaginal veins that accompany arteries with identical names. The mentioned veins drain into the internal iliac vein.

Unlock with Premium

Female urethra