Retrolisthesis

Saturday, 06 March 2010 16:56

A retrolisthesis is a posterior displacement of one vertebral body with respect to the adjacent vertebrae to a degree less than a luxation (dislocation). Clinically speaking, retrolisthesis is the opposite of spondylolisthesis (anterior displacement of one vertebral body on the subjacent vertebral body). In the past this clinical pathology was also called a "retrospondylolisthesis". (2) Retrolistheses are most easily diagnosed on lateral x-ray views of the spine. Views, where care has been taken to expose for a true lateral view without any rotation, offer the best diagnostic quality.

Spondylolisthesis

Saturday, 06 March 2010 16:49

Spondylolisthesis describes the anterior displacement of a vertebra or the vertebral column in relation to the vertebrae below. It was first described in 1782 by Belgian obstetrician, Dr. Herbinaux. He reported a bony prominence anterior to the sacrum that obstructed the vagina of a small number of patients. The term “spondylolisthesis” was coined in 1854, from the Greek “spondyl” for vertebrae and “olisthesis” for slip. The variant "listhesis" is sometimes applied in conjunction with scoliosis. These "slips" occur most commonly in the lumbar spine.

X-ray picture of a grade 1 isthmic spondylolisthesis at L4-5

Arachnoid cyst

Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three membranes that cover the brain and the spinal cord. Arachnoid cysts are a congenital disorder, and most cases begin during infancy; however, onset may be delayed until adolescence.

arachnoid cyst