Objective: This research aimed to define the relationship between the lower lumbar disc herniation and the morphology of the iliolumbar ligaments using magnetic resonance imaging.

Method: 24 male and 36 female patients were classified into two groups according to their disc herniation grade- those in whom the L5-S1 disc was less herniated than L4-5 disc, those in whom the L5-S1 disc was more herniated than the L4-L5 disc on magnetic resonance images. The lengths of iliolumbar ligaments were measured on T1- weighted coronal images. The angles of iliolumbar ligaments were measured on T1-weighted axial images.

Results: The length of iliolumbar ligament was not different between L4-L5 disc herniation and L5-S1 disc herniation. The degree of iliolumbar ligament angle difference (asymmetry of direction) at L5-S1 disc herniation was more deviated in paracentral disc herniation compared with central disc herniation.

Conclusion: The morphology of the iliolumbar ligament, especially its asymmetry of direction, may be a factor influencing the development of disc herniation at L5-S1. (J Korean Acad Rehab Med 2002; 26: 439-444)

Method: Fourteen iliolumbar ligaments of seven human cadavers were dissected and measured distance from the lumbar spinous process to the iliolumbar ligament and vertical depth of iliolumbar ligament from the skin surface.

Results: All 14 iliolumbar ligaments were originated at the L5 transverse process and inserted in anterior surface of the iliac crest. Direct distance from lumbar spinous process to the origin siteof the iliolumbar ligament was 7.67⁑0.39 cm (distance from the spinous process to presumed skin point of the termination site of the ligament, 6.71⁑0.4 cm). Vertical depth from skin surface was 3.94⁑0.57 cm to the origin site of the iliolumbar ligament, and 3.67⁑0.54 cm to the termination site of the iliolumbar ligament.

Conclusion: The iliolumbar ligament was deep seated anatomical structure in the lumbosacral region. Superficial landmark of the lumbar spinous process may be useful in approach to iliolumbar ligament. (J Korean Acad Rehab Med 2003; 27: 974-977)