lumbarization

A congenital anomaly of the lumbosacral junction characterized by development of the first sacral vertebra as a lumbar vertebra, resulting in six lumbar vertebrae instead of five.

* * *

lum·bar·i·za·tion .ləm-bə-rə-'zā-shən n a condition marked by fusion of the first sacral and last lumbar vertebrae

* * *

lum·bar·iza·tion (lum″bər-ĭ-zaґshən) a condition in which the first segment of the sacrum is not fused with the second, so that there is one additional articulated vertebra and the sacrum consists of only four segments.