Lumbar spinal canal
The lateral lumbar spinal canal may be subdivided into the subarticular (lateral recess), the foraminal (pedicle) and the extraforaminal (far lateral) zone. Within these regions lies the “Macnab's hidden zone.”, an area known for its difficult surgical exposure 1).
Lumbar spinal canal dimensions
1)
Macnab I. Negative disc exploration. An analysis of the causes of nerve-root
involvement in sixty-eight patients. J Bone Joint Surg Am. 1971
Jul;53(5):891-903. PubMed PMID: 4326746.