Renal fascia

The kidney and the adipose capsule are enclosed in a sheath of fibrous tissue continuous with the subperitoneal fascia, and named the renal fascia (Toldt's fascia). At the lateral border of the kidney the renal fascia splits into an anterior and a posterior layer. The anterior layer is carried medialward in front of the kidney and its vessels, and is continuous over the aorta with the corresponding layer of the opposite side. The posterior layer extends medialward behind the kidney and blends with the fascia on the Quadratus lumborum and Psoas major, and through this fascia is attached to the vertebral column.

Above the suprarenal gland the two layers of the renal fascia fuse, and unite with the fascia of the diaphragm; below they remain separate, and are gradually lost in the subperitoneal fascia of the iliac fossa. The renal fascia is connected to the fibrous tunic of the kidney by numerous trabeculæ, which traverse the adipose capsule, and are strongest near the lower end of the organ.

With the new consideration (1) as the mesentery as a continuous single organ, the term Toldt's fascia has been redefined:

Toldt’s fascia is contiguous as confi rmed by high-magnification and high-definition intraoperative imaging during laparoscopic (and in particular robotic) surgery and has various names for the different regions.

• Where it surrounds perirenal fat, it is frequently referred to as Gerota’s fascia.

• Beneath the left and right colon it is called Toldt’s fascia. At this point it has been erroneously called the vestigial right and left mesocolon.

• Beneath the right and left mesocolon it is also referred to Toldt’s fascia.

• Continuing under the mesosigmoid, into the pelvis, and separating the mesorectum from the bony pelvis, the fascia is called the mesorectal fascia.

• Where the mesorectum terminates above the pelvic floor, a space occurs. Where the fascia fills this space, it is termed Waldeyer’s fascia.

For some authors, these regions and the entire fascial layer could be collectively referred to as Toldt’s fascia, with the different regions denoted by the region of associated mesentery (ie, mesosigmoidal, mesorectal, mesocolon, and mesenteric regions), but we reprove the use of eponym for official nomenclature in anatomy. This point should be clarified in the futur.