Pelvic Ureter

1. Overview

The pelvic ureter is the terminal segment of the ureter, the muscular tube that conveys urine from the kidneys to the bladder. Specifically, the pelvic ureter begins as the ureter enters the pelvic brim and ends at the point where it reaches the posterolateral aspect of the urinary bladder. This segment plays a crucial role in guiding urine through the narrow confines of the pelvis, while also navigating closely with various pelvic organs and vasculature.

2. Location

The pelvic ureter lies within the true pelvis, following a curved pathway before inserting into the bladder wall. The course varies slightly between sexes:

In Both Sexes:

• Begins at the pelvic brim, medial to the sacroiliac joint.

• Descends anteriorly and medially along the lateral pelvic wall, over the iliac vessels.

• Travels toward the bladder base, where it enters obliquely into the trigone of the bladder.

In Males:

• Crossed anteriorly by the vas deferens near the bladder.

• Lies posterior to the seminal vesicles and lateral to the rectum.

In Females:

• Passes beneath the uterine artery (“water under the bridge”) near the lateral fornix of the vagina.

• Runs lateral to the cervix and upper vagina before entering the bladder.

3. Structure

The pelvic ureter has a tubular, layered structure designed to transport urine efficiently while resisting backflow and external compression:

• Length: Approximately 5–7 cm (as part of the ~25–30 cm long ureter).

• Wall layers:

  • Mucosa: Lined with transitional epithelium (urothelium), allowing distention.

  • Muscularis: Inner longitudinal and outer circular layers of smooth muscle (reverse orientation compared to GI tract).

  • Adventitia: Connective tissue with blood vessels, lymphatics, and nerves.

4. Function

The pelvic ureter serves as a conduit for urine and contributes to unidirectional flow from the kidney to the bladder. Its specific functions include:

• Urine transport: Moves urine via peristaltic waves initiated by pacemaker cells in the renal pelvis.

• Unidirectional flow: Prevents retrograde urine movement via oblique bladder insertion.

• Adaptability: Withstands compression from surrounding pelvic structures without collapse.

5. Physiological Role(s)

Though not involved in filtration or reabsorption, the pelvic ureter contributes to key physiological processes:

• Peristaltic conduction: Smooth muscle contractions move urine at 1–5 peristaltic waves per minute depending on hydration status.

• Valve-like entry: The intramural part of the ureter enters the bladder at an angle that acts as a physiological valve, preventing vesicoureteral reflux.

• Responsive to volume: Ureteral peristalsis increases in response to renal pelvis distension, ensuring timely drainage.

6. Clinical Significance

Ureteric Calculi (Stones)

The pelvic ureter is one of the common sites of obstruction by ureteric stones, especially where it crosses the pelvic brim or enters the bladder wall. Symptoms include:

• Severe flank or groin pain (renal colic)

• Hematuria

• Nausea and vomiting

Stones are best diagnosed via non-contrast CT scan.

Iatrogenic Injury (Especially in Females)

Due to its proximity to the uterus, cervix, and pelvic vasculature, the pelvic ureter is at high risk during:

• Hysterectomy

• Pelvic lymph node dissection

• Endometriosis surgery

Injury can result in ureteral transection or ligation, leading to hydronephrosis, urinoma, or fistula formation.

Vesicoureteral Reflux (VUR)

Improper development of the ureterovesical junction (often involving the intramural pelvic ureter) may result in urine flowing backward into the ureters and kidneys. Common in children and associated with recurrent UTIs and renal scarring.

Ureteral Strictures or Compression

Pelvic tumors (e.g., cervical cancer, colorectal carcinoma) or fibrosis can externally compress the ureter, causing obstruction and hydronephrosis. Managed via ureteral stenting or surgical bypass.

Ureteric Reimplantation

Surgical procedures may reimplant the pelvic ureter into the bladder (e.g., to correct reflux or bypass injury). Knowledge of its anatomy is essential to preserve function and prevent complications.

Imaging and Visualization

The pelvic ureter is assessed using:

• CT urography: Gold standard for detecting stones, strictures, or masses.

• Intravenous pyelogram (IVP): Outlines the course and any delay in urine flow.

• Cystoscopy with retrograde pyelography: Direct visualization in urological procedures.