A brief discussion on lumbar lateral bending

Most lumbar disc herniations protrude posterolateral, away from the center of the body. Once lateral the disc can lie either lateral or medial to the nerve root, the terms lateral &medial refer to the relationship between the disc and the nerve root NOT the relationship to the midline.  A lateral presentation finds the patient leaning away from the side of pain, medial leaning into the pain side.

Antalgia can help differentiate these two conditions and improve clinical treatment choice. Leaning the patient in the opposite direction increases radicular irritation in both conditions. However like extension pain at the initial motions, tolerance and improvement to repetitive motions signals a potential ‘directional preference’ and a less recalcitrant presentation in some cases. Many times patients will present with antalgia in more than one position and this needs to be taken into account as well.

Though Kemps test has been used to differentiate facet involvement its indications by some authors suggests a herniation differential in the case of antalgia as well. It is often done in the seated posture to increase IDP. Antalgia noted before these tests, resistance to lateral bending into and opposing antalgia and the resultant changes in back/leg pain must be taken into account in interpretation.