Home › Human Anatomy › Ureter: Anatomy, Parts, Constrictions and Relations

Ureter

For medical students2 min readUpdated 2026-10-10

The ureter is an essential paired tubular organ of the urinary system responsible for directed urine transport. It connects the renal pelvis to the urinary bladder, ensuring continuous fluid propulsion via active peristaltic contractions of its wall.

LengthAverages about 30–35 cm

PartsDivided into abdominal and pelvic parts

ConstrictionsHas three physiological constrictions along its course

Macroscopic Structure and Parts

Anatomically, the ureter is a hollow muscular tube approximately 30–35 cm in length. Its primary function is the uninterrupted delivery of urine from the kidneys to the reservoir (the urinary bladder).

Topographically, the organ is typically divided into two main parts:

Abdominal part (pars abdominalis) — the upper segment, running in the retroperitoneal space.
Pelvic part (pars pelvina) — the lower segment, located within the lesser pelvis.

As urine moves downward, the muscular elements of the organ generate peristaltic waves, allowing fluid to actively enter the urinary bladder regardless of body position.

Physiological Constrictions of the Ureter

The lumen of the organ is not uniform. Along its course, there are three characteristic physiological constrictions of major clinical significance (for example, kidney stones frequently lodge at these sites during nephrolithiasis):

Ureteropelvic junction — the site where the renal pelvis (pelvis renalis) transitions into the ureter (ureter).
Pelvic brim constriction — the zone where the ureter crosses the major iliac vessels upon entering the pelvic cavity from the abdomen.
Intramural part — at the site where the organ pierces the wall of the urinary bladder.

Histological Structure of the Wall

The ureteric wall is well-adapted for distension and active contractions. It consists of three distinct layers:

Mucosa (tunica mucosa) — the inner layer lining the lumen of the organ.
Muscularis (tunica muscularis) — the middle layer formed by smooth muscle cells. It consists of longitudinal and circular bundles that drive peristalsis.
Adventitia (tunica adventitia) — the outer connective tissue layer fixing the organ to surrounding tissues.

Topographical Features in Males

In the male pelvis, the path of the ureter features specific crossings with reproductive organs:

Just before entering the wall of the urinary bladder, it crosses the ductus deferens (vas deferens). The ductus deferens lies medial to the ureter.
The ureteric opening into the urinary bladder projects below the floor of the rectovesical pouch of the peritoneum.
The point of entry anatomically corresponds to the apex of the seminal vesicle.

Topographical Features in Females

In females, the syntopy (spatial relationship with neighboring structures) of the ureter is particularly complex and critical for operating surgeons and gynecologists:

First, the ureter crosses the origin of the uterine artery, lying more superficially relative to it.
Next, it courses medially, inferiorly, and anteriorly, passing through the parametric connective tissue (parametrium).
At the level of the cervix uteri, it crosses the uterine artery a second time, but here the ureter lies inferior to the vessel.

Clinical Significance: The close and complex entanglement of the ureter with the uterine artery creates a high risk of accidental injury (ligation or transection) during gynecological procedures, such as a hysterectomy.

Mnemonic

Remember the three constrictions easily with the formula "Start — Crossing — Finish": ureteropelvic junction (start), crossing of the iliac vessels (crossing), and entry into the urinary bladder (finish).

Frequently asked questions

What epithelium lines the mucosa of the ureter?

The mucosa of the ureter is lined by stratified transitional epithelium (urothelium) facing the lumen. A distinctive histological feature of this epithelium is that the nuclei of its superficial cells are round. Directly beneath the epithelial layer lies the lamina propria (lamina propria). The muscularis mucosae is completely absent in the ureter.

Which arteries supply the abdominal part of the ureter?

The abdominal part of the ureter is supplied by ureteric branches of the renal arteries (rr. ureterici), as well as small branches from the common iliac arteries. The renal artery gives off ureteric branches prior to the renal hilum and from its posterior branch.

How is the ureter positioned relative to the peritoneum?

The ureter is located retroperitoneally relative to the peritoneum.

Abdominal part (pars abdominalis) — located retroperitoneally in the retroperitoneal space of the posterior abdominal wall.
Pelvic part (pars pelvina) — lies in the subperitoneal tissue of the lesser pelvis (subperitoneal space).

Throughout its length, the ureters are surrounded by periureteric fat and possess their own fascial sheath.

Which lymph nodes drain lymph from the pelvic part of the ureter?

Lymph from the pelvic part of the ureter drains into the iliac lymph nodes.

Which autonomic plexuses innervate the ureter?

The ureter is innervated by branches of several autonomic plexuses.

Superior hypogastric plexus — contributes to the innervation of the pelvic segments of the organ.
Inferior hypogastric plexus — also supplies innervation to the pelvic segments of the ureter.

Additionally, the lower part of the ureter receives parasympathetic innervation sourced from the pelvic splanchnic nerves (nn. splanchnici pelvini).

What is the average length of the ureter in an adult?

Normally, the length of the ureter is about 30–35 centimeters.

Which layers make up the muscular coat of the ureter?

The muscular coat (tunica muscularis) is formed by longitudinal and circular layers of smooth muscle.

How is the ureter positioned relative to the uterine artery near the cervix?

At the level of the cervix, the ureter crosses the uterine artery, lying inferior to it (underneath the artery).

Where does the ureteric entry into the bladder project in males?

It is located below the floor of the rectovesical pouch and corresponds to the level of the apex of the seminal vesicle.

Go deeper

Mechanism of ureteric peristalsis
Anatomy of the rectovesical pouch
Topography of the parametric tissue (parametrium)
Syntopy with the iliac vessels
Course of the ductus deferens in the lesser pelvis