• A short trunk, which unites with the external iliac to form the common iliac vein.
  
  
• Its tributaries correspond in general to the branches of the internal iliac artery, with the exception of the umbilical and the iliolumbar arteries.
  
  
• Each of the viscera within the pelvis is surrounded by a network of relatively large, thin-walled veins, which have few valves.
  
  
• These plexuses communicate freely with each other and give rise to the visceral tributaries of the internal iliac vein.
  
  
• They also communicate with the parietal tributaries, and thereby provide easy pathways for the spread of infections.
  
  
• The plexuses are named as follows:

1) The Rectal venous plexus

2) The Vesical venous plexus

3) The Prostatic venous plexus

4) The Uterine venous plexus

5) The Vaginal venous plexus

6) The Sacral venous plexus