What are the extraperitoneal spaces of the pelvis?
The prevesical space, also called the retropubic space or the space of Retzius, is an extraperitoneal space located anterior and lateral to the umbilicovesical fascia (UVF) and posterior to the pubic bones, extends posteriorly to communicate with the presacral space, and contains fat. It is a large potential space with multiple potential extensions and communications, allowing for bidirectional spread of fluid collections and other disease processes into the retroperitoneum and thighs. Prevesical fluid collections typically have a “molar tooth” configuration in the axial plane and can be large in size ( Figure 37-2 ). The perivesical space is a small extraperitoneal space bounded by the UVF which contains the urinary bladder, urachus, obliterated umbilical arteries, and fat. Perivesical fluid collections are typically small in size. The perirectal space is surrounded by the perirectal fascia and contains the rectum, hemorrhoidal vessels, and fat.