Atlanto-occipital joints

Study entry

Classification

Condylar synovial joints, one on each side, with no intervertebral disc.

Surfaces

Superior articular surfaces of the lateral masses of the atlas (C1) with the occipital condyles.

Capsule

Own capsules; the skull and C1 are also connected by the anterior (wide, dense fibers, continuous with the anterior longitudinal ligament) and posterior (wide but weak) atlanto-occipital membranes, from the anterior and posterior arches of C1 to the anterior and posterior borders of the foramen magnum; the vertebral arteries pierce the posterior one before entering the foramen magnum. The membranes help prevent excessive movement.

Movements

Flexion and extension of the head (as in nodding "yes"); the main movement is flexion, with little lateral flexion and rotation.

Blood supply

[CHECK: Moore does not describe it in the passages consulted (look in another source).]

Innervation

[CHECK: Moore does not describe it in the passages consulted (look in another source).]

Source: cap. 2, «Articulaciones craneovertebrales»

Other structures in this region

• Ligamenta flava
• Cruciate ligament of the atlas (transverse ligament and longitudinal bands)
• Alar ligaments
• Tectorial membrane
• Anterior and posterior atlanto-occipital membranes
• Lumbosacral joints
• Joints of the vertebral bodies (intervertebral discs)
• Zygapophysial (facet) joints