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Anterior sacrodural attachments - Trolard's ligaments revisited.

In contrast to the attention paid to the structures surrounding spinal nerve roots in the intervertebral foramina, the anterior dural attachments are largely ignored, although they have been described since the last decades of the 19th century. These anterior attachments were systematically studied in a series of 30 cadaver dissections and were found to be present in almost 94% of cases. Four types of anterior attachments were observed. The most frequent form (84%) being a system of filaments that present as a double cross vault between the dura mater and the posterior longitudinal ligament extending from L3 to S3 levels. Less frequent were sagittal filaments (30%), short strong ligaments (17%) and a median septum from L3 to the end of the dural sac (7%). No attachments were found in two cadavers. Further studies are needed to clarify the possible role of these structures in transmitting movement to the dural sac and periradicular sleeves when mobilising the last three lumbar vertebrae or the sacrum.