Spondyloslisthesis a condition where the vertebral body slips out of its place and rest on the bone below it 

spondylos (spine or vertebra) and listhesis (slipping, sliding or movement) 

• approximately 90% of spondylolisthesis occurs at the L5-S1 junction 

•  the vertebral bodies may lose some height or the interspace may narrow 

•  there are three (3) types of spondylolisthesis:

i. degenerative spondylolisthesis (most common) 

ii. isthmic spondylolisthesis

iii. congenital spondylolisthesis