What is break noted in pars interarticularis between l5 s1 level?

Spondylolysis: Spondylo means spine and lysis means crack. These can be congenital variety which is genetic in origin occuring in 6% of the us population or after trauma which can be repetitve particularly in certain high level athletes like swimmers, gymnasts, pitchers, football linemen to name a few. Most are treated non operatively. It can be from trauma too. They can be found in about 6% of the us