Department of Orthopaedic Surgery, Klinikum Esslingen, Hirschlandstrasse 97, 73730, Esslingen a.N, Germany.
Eur Spine J. 2013 May;22 Suppl 3(Suppl 3):S512-6. doi: 10.1007/s00586-013-2768-7. Epub 2013 Apr 11.
The purpose of this study was to examine the anatomic changes in a case of occipitalization of the atlas.
Occipitalization of the atlas was found accidentally in a 64-year-old male cadaver. Anatomic dissection was carried out to examine the posterior aspect of the upper cervical region and craniocervical junction. The occipitalized atlas was then harvested and macerated to study the bony anomaly.
In this case of occipitalization, fusion was observed at both lateral masses and at the left posterior hemiarch of the atlas. We found the following soft tissue changes: the rectus capitis posterior minor muscle was lacking on the left side and was atrophic on the right, the obliquus capitis superior muscle was present on both sides showing moderate atrophy and fatty changes. The posterior atlanto-axial membrane was thinner and asymmetric, had a free edge on the right side. Lateral to this edge the dura was lying free. We believe that these changes of the posterior atlanto-axial membrane together with the increased distance between the fused posterior arch of the atlas and the lamina of the axis could cause the observed "dura bulge" at this level. The vertebral artery was entering the skull through a canal on the left side.
In our case, occipitalization considerably changed the anatomy of the upper cervical spine and craniocervical junction. Special care must be taken when using the posterior approach to avoid neurovascular injury in cases with occipitalization.
本研究旨在探讨寰椎枕化的解剖学变化。
在一具 64 岁男性尸体中偶然发现寰椎枕化。进行解剖学 dissection 以检查上颈区和颅颈连接的后侧面。然后收获并浸软寰椎枕化的寰椎以研究骨异常。
在这个寰椎枕化的病例中，在两侧侧块和寰椎左后半弓观察到融合。我们发现以下软组织变化：左侧头后小直肌缺失且右侧萎缩，头长肌两侧存在，显示中度萎缩和脂肪变性。寰枢后膜较薄且不对称，右侧游离缘。我们认为，这种寰枢后膜的变化以及融合的寰椎后弓与枢椎椎板之间的距离增加，可能导致在这个水平观察到的“硬脑膜膨出”。椎动脉通过左侧的一个管进入颅腔。
在我们的病例中，寰椎枕化极大地改变了上颈椎和颅颈连接的解剖结构。在使用后路时，必须特别小心，以避免在寰椎枕化的情况下发生神经血管损伤。
