Summary
We have examined 203 lumbar and sacral skeletal specimens and have noted the frequent occurence of a mamillo-accessory foramen, formed by the ossification of the mamillo-accessory ligament. The dorsal ramus of the lumbar nerve passes through this foramen. At the L5 level, this foramen is found frequently: in 26% of the cases on the left side and in 13.5% on the right. In some cases it is seen as a simple, deep notch. It is found much less frequently at L4 and almost never seen above. It is equally rare at the sacral level where it is formed by a narrowing and closure of the groove between the zygapophyseal joint and the sacral lateral mass. The authors propose that these bony foramina are a manifestation of osteoarthritic changes and that they could, in certain cases, irritate or compress the dorsal ramus along its passage.
Résumé
Les auteurs ont examiné 203 rachis lombaires et sacrums et ont noté la présence fréquente d'un foramen mamillo-accessoire. Le rameau dorsal du nerf rachidien passe à travers lui. Au niveau de L5, ce foramen est fréquent : 26,4 % des cas à gauche, 13,5 % des cas à droite. Il est parfois remplacé par une simple encoche. Il est beaucoup plus rare sur L4 et quasiment inexistant au-dessus. Il est également rare au niveau du sacrum où il est constitué par un rétrécissement et une fermeture de la gouttière entre zygapophyse et aileron. Les auteurs émettent l'hypothèse que ces foramen osseux sont une manifestation des remaniements arthrosiques et qu'ils pourraient dans certains cas irriter, voire comprimer les rameaux dorsaux qui les traversent.
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Maigne, JY., Maigne, R. & Guerin-Surville, H. The lumbar mamillo-accessory foramen: a study of 203 lumbosacral spines. Surg Radiol Anat 13, 29–32 (1991). https://doi.org/10.1007/BF01623137
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DOI: https://doi.org/10.1007/BF01623137