(transitional vertebral segment): a
congenital anamoly of a vertebra in which it develops characteristics of
the adjoining structure or region, e.g lumbosacral, cervicothoracic. The
clinical significance of this lies in its aberrant motion characteristics;
gross postural effects on the super incumbent spinal column or
pseudoarthrosis between the enlarged transverse processes and either the
sacrum or ilia.
a transitional segment in which the first
sacral segment becomes like an additional lumbar vertebra articulating
with the second sacral segment.
1. Incomplete separation and
differentiation of the fifth lumbar vertebra (L5) such that it
takes on characteristics of a sacral vertebra
2. When transverse processes
of the fifth lumbar are atypically Large, causing
pseudoarthrosis with the sacrum and/or ilia referred to as batwing
deformity if bilateral.