Lower limb pain
is a general term for a condition which has caused inflammation
of or compression
of a major spinal nerve
or nerves which have a pain pattern producing severe burning type pain down the buttock, thigh and calf.
It can come from a problem with any or all the spinal nerves which comprise the sciatic L4 through s3 but most commonly comprises L5 or s1 or it can be pure sciatic pain (out).