Closing of the posterior intervertebral spaces of the craniovertebral joint is not performed by the classical posterior atlantooccipital and atlantoaxial membranes. In the atlantooccipital space, the connective laminae come from the occipital periosteum and from the anterior fascia of the rectus capitis posterior minor muscle, and pass round the anterior side of the posterior arch of the atlas to reach the spinal dura mater. In the atlantoaxial space, the anterior fasciae of the rectus capitis posterior major muscle and of the inferior oblique muscle, as well as the periosteum of the posterior arch of the atlas, extend to reach the spinal dura mater. Thus, the epidural space is ceiled posteriorly by the connective laminae of the atlantoaxial space, and lets above a superior recessus containing the ganglia of the spinal nerves Cl and C2 and in which the vertebral artery transits.