Two vertebral bodies articulate with each other by an intervertebral disc and two synovial . In the lumbosacral spine the nerve root exits the spinal canal through the intervertebral foramen below the corresponding vertebra (e.g. L5 nerve root exits below L5 vertebra.u The disc is composed of a central jelly- like material called nucleus pulposus.u The nucleus has the affinity to imbibe water and become tense to carry axial loads and at the same time it acts as a joint allowing movement between two vertebrae.