MR arthrography for evaluation of the acetabular labrum.

MR arthrography of the hip has provided new insights into the lesions underlying mechanical hip pain. Until now evaluation of these structures, especially the acetabular labrum, has been limited. With the joint distention provided by MR arthrography, labral detachments and intrasubstance tears can be identified and differentiated from the many varied appearances of the asymptomatic labrum. This article reviews the normal anatomy of the hip, the clinical presentation of internal derangement and the technique for performing MR arthrography. The variations in morphology and signal of the asymptomatic labrum are reviewed as well as the appearance of the abnormal labrum.