The Anterior and Posterior Meningeal Branches of the Vertebral Artery

The meningeal branches of the vertebral artery have received little attention in either the radiologic or the anatomic literature. These arteries, which usually are small, may become significantly enlarged in a variety of pathologic conditions. The normal anatomic and roentgen features of these meningeal branches will be reviewed in this communication, and the significance of their enlargement will be discussed. Anatomy Both anterior and posterior meningeal branches of the vertebral artery arise from its extracranial segment to supply a portion of the dura of the posterior fossa. The posterior branch has been described previously (3, 4, 7, 13). It arises from the vertebral artery above the level of the arch of the atlas just below the foramen magnum. This artery supplies the medial portions of the dura of the occipital posterior fossa as well as the falx cerebelli. In addition, it may extend above the tentorium to supply the posterior segment of the falx cerebri and adjacent tentorium. The course and distribution of the posterior meningeal branch were studied in 5 cadavers. Cannulae were placed into the vertebral arteries in the neck, and the arteries were then flushed with water. After division of the tentorium close to the petrous pyramids, the brain was removed and the intradural segment of both vertebral arteries was ligated. The arteries were then filled with a Micropaque gelatin solution using gentle steady pressure by hand. Photographs of the visualized dural arteries as well as roentgenograms of the skull were obtained. The posterior fossa dura was then separated from the calvaria. The dura could be stripped easily from the posterior fossa except at its attachment to the rim of the foramen magnum and petrous pyramids, where transection of the tentorium was required. Roentgenograms of the excised dura were obtained in the lateral and frontal projections. The size of the posterior meningeal branch varied considerably. The artery entered the skull via the lateral portion of the foramen magnum and was located within the dura. The major branch extended to the midline, from which point it coursed superiorly in the falx cerebelli close to its posterior attachment to the skull (Fig. 1). The artery could be followed to above the tentorium, where it supplied the posterior portions of the falx cerebri. Lateral branches, distributed along the posteromedial aspect of the dura of the posterior fossa, were also noted. The anatomic and roentgenologic relationship of the anterior meningeal branch of the vertebral artery was recently described by Greitz and Lauren (5), who observed on anatomical dissections that this artery arose from the vertebral artery immediately below its first bend at the level of the axis.