Lamina: The portion of bone that extends from the pedicle and curves around to complete the vertebral arch on the right and left sides.
Laminectomy: Removal of one or more entire lamina. Used when greater access is needed to perform a discectomy. Helps release pressure on the nerve when a disc bulges.
Laminotomy: A surgical procedure where part of the lamina of a vertebra is removed for access to the disc.
Leptomeninges: Two thin layers of fine tissue covering the brain and spinal cord (the pia mater and arachnoid).
Leptomeningitis: Inflammation of the membranes covering the brain and spinal cord.
Lipoma: A benign fatty tumor, usually composed of mature fat cells.
Lordosis: Curvature of the spine with the convexity forward.
Lumbar drain: A device (usually a long, thin flexible tube) inserted through the skin into the cerebrospinal fluid space of the lower back; provides a method of draining cerebrospinal fluid.
Lumbar puncture (spinal tap): Diagnostic test in which a sample of cerebrospinal fluid is "tapped" from an area just below the end of the spinal cord through a thin needle inserted into the spinal canal. Used to detect blood in the cerebrospinal fluid.
Lumbar spine: Lower spine, lower back. Usually consists of five vertebrae.