MICROSURGICAL ANATOMY OF THE SUBOCCIPITAL SEGMENT OF THE VERTEBRAL ARTERY

The craniocervical regions of seven cadavers (14 sides) injected with silicone rubber were dissected under a Zeiss OPMI surgical microscope. The present study provides a detailed description oi the suboccipital segment of the vertebral artery, with particular attention to its loo ps, branches, supporting osteofibrous structures, adjacent nerves, and surrounding venous structures. Several ligaments fixating the vertebr al artery to surrounding structures, which have not been described in previous anatomical studies, were found. The authors propose an anatom ically based subdivision of the suboccipital segment of the vertebral artery into five subsegments: infraforaminal, foraminal, supraforamina l, horizontal, and intramembranous. Measurements of surgically and cli nically important features were obtained. Surgical approaches to this region are suggested based on a more informed understanding of the loc al anatomy.