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)

Keywords :Iliolumbar ligament, Disc herniation, Magnetic resonance imaging