Anatomic considerations of the posterolateral lumbar disk region

Sixteen embalmed cadavers were dissected to determine the location of the l umbar nerve root and sympathetic trunk with reference to the superior borde r of transverse process. In the posterolateral lumbar disk region, a safe z one was found between the anterior limit of the lumbar nerve and the poster ior limit of the sympathetic trunk. It has a transverse dimension of 22mm a t the T12-L1 disk region and 25 mm at the L4-L5 disk region. The only excep tion to this was the genitofemoral nerve running close to the lateral margi n of the L2-L3 disk. The study provides an understanding of the posterolate ral orientation of the lumbar nerves and sympathetic trunk.