Espiral AtlasAnterior and posterior atlanto-occipital membranes
membranae atlantooccipitales
Study entry
Classification
Fibrous membranes of the atlanto-occipital joint.
Surfaces
From the anterior and posterior arches of the atlas to the anterior and posterior margins of the foramen magnum. Laterally, they blend with the capsules of the atlanto-occipital joints.
Capsule
The anterior has wide, dense fibers, continuous in the middle with the anterior longitudinal ligament. The posterior is wide but weak, and continues the series of the ligamenta flava.
Movements
They help prevent excessive movement of the atlanto-occipital joints.
Blood supply
Spinal branches of the segmental arteries of the level, which supply the bones, the periosteum, the ligaments and the meninges around the epidural space: in the neck, from the vertebral and ascending cervical arteries; in the thorax, from the posterior intercostals; in the abdomen, from the subcostal and lumbar arteries; in the pelvis, from the iliolumbar and the lateral and median sacral arteries.
Innervation
Meningeal (recurrent) branches of the spinal nerves. They arise just after the nerve forms, return through the intervertebral foramen and supply the periosteum, the ligaments (especially the anterior longitudinal), the meninges and the annuli fibrosi of the discs. They carry pain from these structures.
Clinical
The vertebral arteries pierce the posterior atlanto-occipital membrane before passing through the foramen magnum.
Source: cap. 2, «Articulaciones craneovertebrales»; figs. 2-20 B e 2-21; «Vascularización de la columna vertebral» e «Nervios de la columna vertebral»