The peridural membrane of the spinal canal: a critical review.

There exists substantial evidence that a peridural membrane (PM) is present in the spinal canal of humans and, like the pleura and peritoneum, has one or more physiologic functions. Innervation of the PM suggests that it may become a source of pain if injured. Although debated, the physiology of this structure has important implications with respect to neuraxial distribution of drugs and for back and radiating pain. This review, separated into embryological, anatomic, and physiologic discussions, provides an in-depth summary of the observations of this connective tissue. The discrepancies between accounts are highlighted within each section. Focused research to clearly elucidate the true nature of the PM, especially as related to neuraxial distribution of drugs and back and radiating pain, is warranted.