Magnetic resonance images of a true epidural lipomatosis. A T1-weighted cross-sectional image of a true epidural lipomatosis at the lumbar level of LEL 3 (according to Borré). There is a large intraspinal space, which is filled by an excessive amount of epidural fat (white arrows) and squeezes the cerebrospinal fluid away so that the dural sac (black arrow) completely surrounds the bundle of nerve roots and leaving no free intradural cerebrospinal fluid volume (dural sac cross-sectional area of only 48 mm2). These nerve roots are not completely free to move away when a needle is inserted into the dural sac.