ILIOLUMBAR LIGAMENTS VS. SCIATIC NERVE ENTRAPMENT ⠀ The primary role of the iliolumbar ligaments (ILL) is to prevent excessive lumbar sidebending, but these ligaments can contribute to sciatic nerve (SN) entrapment when injured. ⠀ A traumatic event such as a bending and twisting maneuver while attempting to lift a heavy object, may strain the ILL and their multifidi neighbors. ⠀ As the ILL weaken, they lose the ability to prevent the fifth lumbar vertebra from shifting forward on the sacrum which may cause contralateral narrowing of the intervertebral foramen, facet arthrosis and possible SN entrapment. Corrective exercises such as planks and bird-dogs may, in time, restore strength and stability to these stretch-weakened ligaments. ⠀ In extreme cases, slippage of the fourth or fifth lumbar vertebra may result in spondylolisthesis, where the pars interarticularis cracks from excessive pressure, allowing SN entrapment on one or both sides . ⠀ Yet, one of the lesser-appreciated areas for SN occlusion lies beneath the anterior ILL. First discovered by famed anatomists Drs. Philip Hanson and Bill Sonesson, notice in Pic 5, how these taut bands on the anterior surface form “fascial hoods” over the L4 and L5 nerve roots. ⠀ Once the greater SN leaves the spine, it must traverse through these taut bands. In a nicely aligned pelvis, this usually presents no compression problems. But visualize how a torsioned pelvic bowl could bind the anterior ILL against the pelvic bowl occluding the underlying SN roots . ⠀ In the beginning, the client may or may not experience symptoms depending on the brain’s perception of the degree of threat. However, prolonged nerve root compression may begin to obstruct axoplasmic transport of proteins and other cell parts to and from the neuron’s cell body. Clinically, this breakdown of nerve conduction may lead to what Harvard University plastic surgeons Albert Upton and Alan McComas called “double crush syndrome.” ⠀ This term refers to scenarios where compressed axons at one site cause the nerve to become especially susceptible to damage at another site, such as under the piriformis muscle.