Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2002

Special Part
Urinary System, systema urinarium - General Overview
Urinary Organs - Ureter

The Ureter, ureter, is a paired organ through which urine flows from the renal pelvis into the Urinary Bladder (Fig. 311). It is shaped like a cylindrical tube, slightly flattened, with a diameter of 0.4–0.7 cm and a length ranging from 25 to 34 cm, depending on the height of the Kidneys.

Three PARTS OF THE ureter are distinguished: the abdominal part, pars abdominalis, the pelvic part, pars pelvica (separated by the terminal line, linea terminalis), and the intramural part, pars intramuralis. The ureter has three constrictions:

- at the exit from the renal pelvis (pelvic constriction),

- at the crossing of the common iliac vessels,

- at the site of entry into the urinary bladder.

Dilatations are located between these constrictions. Knowledge of the ureteral constrictions is of great importance in urological practice, as they are common sites where calculi become lodged during their passage along the ureter in urolithiasis.

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Fig. 311. The ureter, ureter.

A - constrictions of the ureter: 1 - pelvic constriction; 2 - at the crossing of the common iliac vessels; 3 - at the site of entry into the urinary bladder; B - cross-section of the ureter: 1 - tunica mucosa; 2 - stratum circulare tunicae muscularis; 3 - stratum longitudinale tunicae muscularis; 4 - tela submucosa

The ureter obliquely pierces the wall of the urinary bladder and opens into it via the ureteral orifice, ostium ureteris. In newborns, the ureter is 5–7 cm long. In two-year-old children, its length is already twice as great, in three-year-old children—three times, and it reaches its final adult length by the age of 18–25 years.