Microsurgical anatomy of the region of the foramen magnum.

The anatomy needed to plan microoperative approaches to the region of the foramen magnum was examined in 25 cadaveric heads. The structures examined included the lower cranial and upper spinal nerves, the caudal brain stem and rostral spinal cord, the vertebral artery and its branches, the veins and dural sinuses at the craniovertebral junction, and the ligaments and muscles uniting the atlas, axis, and occipital bone. The transoral, transpalatal, labiomandibular, glossolabiomandibular, transsphenoidal, transcranial-transbasal, transcervical, and suboccipital operative approaches to the region are also reviewed.