Atlantooccipital membrane

Atlantooccipital Membrane is a fibrous membrane that spans between the atlas and the occipital bone, in the human anatomy. It is part of the craniovertebral junction, which is a complex joint that allows for a wide range of movements of the head.

Anatomy

The atlantooccipital membrane is divided into two parts: the anterior atlantooccipital membrane and the posterior atlantooccipital membrane.

The anterior atlantooccipital membrane is a broad but thin membrane, which connects the anterior arch of the atlas to the anterior margin of the foramen magnum. It is in front of the vertebral artery and the sympathetic trunk, and behind the longus capitis muscle and the rectus capitis anterior muscle.

The posterior atlantooccipital membrane is a thin and broad membrane, which connects the posterior arch of the atlas to the posterior margin of the foramen magnum. It is behind the vertebral artery and the first cervical nerve, and in front of the rectus capitis posterior minor muscle and the obliquus capitis superior muscle.

Function

The atlantooccipital membrane serves to stabilize the craniovertebral junction and limit its movements. It prevents excessive movement of the head in relation to the neck, thus protecting the spinal cord from injury.

Clinical significance

Injuries to the atlantooccipital membrane can occur due to trauma, such as in whiplash injuries or in atlanto-occipital dislocation, which is a severe and often fatal injury. In addition, diseases such as rheumatoid arthritis can affect the atlantooccipital membrane and lead to instability of the craniovertebral junction.

See also

• Atlanto-axial joint
• Ligament
• Cervical vertebrae