The World of Pregnancy

Urethra In Women: Anatomy, Physiology & Pathology

The female urethra isn`t too long and represents the urinary system`s final pathway, where the urine gets removed to the exterior of the body.

Urethra In Women

Anatomy / Structure

The urethra starts the urethral bladder opening, around 3 cm behind the pubic symphysis, then passes through the urogenital diaphragm, only to end with the external urinary tract, which is located the vaginal vestibule.

This has an oblique, downward and rearward trajectory. There are 2 parts described:

  • Pelvic;
  • Perineal.

The average length is of 3 to 5 cm and the diameter is of around 7 to 8 mm.

The urethra is a bit distensible, which is also the reason why it`s great for catheterization, but the less elastic region is at the external opening.

The urethra`s lining has longitudinal folds and one of them has rear localization and is known as urethral crest.

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A common characteristic between the woman`s urethra and the one of a man is the presence of urethral gaps as well as urethral orifices.

The urethra`s wall is made of:

  • Mucosa: it`s elastic, thin and includes the urothelial epithelium in the upper part and the stratified cylindrical epithelium in the inferior part. It has many mucous glands as well as a venous plexus at the level of the corion.
  • Muscular: It has an internal longitudinal layer as well as an outer circular layer.
  • Adventitia:

The urethral sphincter device consists of:

  • The urethral smooth sphincter, condensation of the muscular circular fibers, which is still in the fibers of the bladder, surrounding the initial part of the urethra.
  • The external sphincter: it`s striated and belongs to the urogenital diaphragm. It also surrounds the smooth sphincter in the exterior part and extends all the way from the bladder to the urogenital diaphragm, adhering to its fascicles.

The Skene paraurethral ducts are 2 symmetrical channels that are partially covered by the urethral muscular tunic as well as posterolateral by the urethra. These ducts have a length somewhere between 0.5 and 3 cm and the mucous urethral glands open at their level.

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The external opening is located at the vaginal vestibule, around 2 cm behind the woman`s clitoris. The posterior will feature a prominence of the vaginal mucosa known as the urethral carina, an essential feature in the urethra catheterization. – Read this!

Arterial vascularization of the urethra:

  • Pelvic segment: it includes the lower vesicular arteries, long vaginal artery and anterior vesicular arteries.
  • Perineal segment: bulbous and bulbo-uretrake arteries.

Venous vascularization of the urethra:

  • Venous plexus mucous drainage then in bulbous veins and perivezical venous plexus.

Lymphatic vascularization of the urethra:

  • It drains in the external and internal iliac lymph nodes.

Urethral innervation:

  • It`s provided by the hypogastric plexus.

Reports with the Neighboring Structures (Topography)

The pelvic segment, having around 2 or 3 cm in length, has the following ratios:

  • Anterior: pubo-vesicular ligaments, deep dorsal vein of the clitoris and venous plexus.
  • Posterior: the anterior wall of the vagina, where it determines the formation of the previous vaginal cervix. – More info!
  • Lateral: anal lift muscles.

The perineal segment, having around 1 cm in length, crosses the urogenital diaphragm, adhering tightly to it and having the following ratios:

  • Anterior: perineal transverse ligament.
  • Posterior: vagina;
  • Lateral: the deep transverse muscle of the perineum.

Physiology of Urethra – Role, Functions & Mechanisms

The urethra is generally involved in removing the bladder`s urine to the exterior, and its evacuation is controlled by vesicular sphincters:

  • The internal bladder sphincter, which prevents the urine from entering the urethra and prevents its removal until the intravesical pressure exceeds a specific limit.
  • The external bladder sphincter can be controlled voluntarily, and prevents obstruction even in cases where there`re involuntary nerve impulses which command the bladder`s evacuation.

Symptoms Associated with the Urethra

  • Dysuria;
  • Oligo/anuria;
  • Urethral colic.

Pathology Associated with Urethra

In women, all the diseases related to the urethra can be split into the following categories:

  • Inflammatory disease;
  • Congenital defects of the urethra structure;
  • Functional disorders of neuromuscular regulation;
  • Urethral stricture;
  • Benign tumors (lax cysts, polyps);

The inflammation of the mucosa is known as urethritis. The cause of this medical condition is pathogens which enter the urethra. The signs might vary a lot depending on the pathological process. The most frequent ones are frequent urination, pain and burning.

When cancer is concerned, it was noticed other symptoms like bleeding of the urethra and sharp pains.

The malformations of the urethra are quite rare, but some of them are:

  • Congenital fusion of the urethra (a medical condition which requires surgery in the very first few days after giving birth); – Click on this link!
  • Urethral duplication;
  • Cystic urethra;
  • Congenital partitions which are located in the lumen of the urethra;
  • Urethral diverticulum;
  • Congenital terrain narrowing of the urethra.

Urethral Evaluation

  • Objective Examination: anamnesis, urological examination, physical consultation;
  • Lab investigations;
  • Paraclinic examinations: MRI, CT, imaging, ultrasound.
Image courtesy of desertwomenscare.com
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