Iliolumbar ligament insertions - In vivo anatomic study

Study Design. Using magnetic resonance imaging, this study analyzed the anatomic characteristics of the iliolumbar ligament insertion on humans. Objectives. To resolve certain anatomic questions about the manner of insertion of the iliolumbar ligament. Summary of Background Data. The data of the postmortem studies of the iliolumbar ligament are controversial because of the number, complexity, and variability of the structures present in the lumbosacral region. Methods. Twenty-eight iliolumbar ligaments of 14 adult volunteers were analyzed with magnetic resonance imaging. The images were acquired along the transversal planes (from inferior to superior) and coronal planes (from the ventral to the dorsal) of the lumbosacral region. Results. The anterior band of the iliolumbar ligament (broad and flat) originates from the anterior-inferior-lateral part of the L5 transverse process and expands as a wide fan before inserting on the anterior part of the iliac tuberosity below the posterior band. The posterior band of the iliolumbar ligament originates from the apex of the L5 transverse process and is thinner than the anterior with a round section, and it inserts on the iliac crest (from the anterior margin to the apex). Conclusions. The minor width of the area of insertion on the iliac crest of the posterior band (and therefore its lower resistance with the mechanical overloads) could explain the frequency of the painful syndromes related, by some authors, to an enthesopathy of this ligament.