The ureter is 25-30 cm long and has three parts:
The ureter begins its descent to the bladder by running along the medial aspect of the psoas muscle. Here, the ureter lies anteriorly and slightly medial to the tips of the L2-L5 transverse processes.
It enters the pelvis anteriorly to the sacroiliac joint at the bifurcation of the common iliac vessels (at the pelvic brim) and then courses anteriorly to the internal iliac artery down the lateral pelvic sidewall.
At the level of the ischial spine it turns forward and medially to enter the posterolateral wall of the bladder, where it runs an oblique 1-2 cm course, before opening into the bladder at the internal ureteric orifice .
The relations of the ureter are somewhat complex due to the differences between the left and right sides of the abdominal cavity and differences between male and female pelvic viscera.
Following the course of the ureter from superior to inferior :
- posteriorly: psoas muscle; genitofemoral nerve; common iliac vessels; tips of L2-L5 transverse processes
- posteriorly: sacroiliac joint, internal iliac artery
- female: cervix
The ureter has a diameter of 3 mm but there are three constrictions, which are the most common sites of renal calculus obstruction:
- at the pelviureteric junction (PUJ) of the renal pelvis and the ureter
- as the ureter enters the pelvis and crosses over the common iliac artery bifurcation
- at the vesicoureteric junction (VUJ) as the ureter obliquely enters the bladder wall
- arterial supply: from branches of the renal artery, abdominal aorta, superior and inferior vesical arteries
- venous drainage: via similarly named veins but is highly variable
- abdominal ureter: aorto-caval and common iliac nodes
- pelvic ureter: internal and external iliac nodes
- derived from renal, aortic and hypogastric autonomic plexuses
The ureteric wall is composed of three layers (from outside to inside):