Definition of Lumbar

Lumbar: Referring to the five lumbar vertebrae, the disks below them, and the corresponding area of the lower back. The lumbar vertebrae and their disks are situated below the thoracic vertebrae and above the sacral vertebrae in the spinal column and are surrounded by soft tissues, including ligaments and large muscles.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=18053
Last Editorial Review: 3/19/2012