Posterior atlantooccipital membrane

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== Posterior atlantooccipital membrane ==

The posterior atlantooccipital membrane is a broad, thin ligament that connects the posterior arch of the atlas (C1 vertebra) to the posterior margin of the foramen magnum of the occipital bone. This membrane is part of the atlanto-occipital joint, which is responsible for the nodding motion of the head.

Anatomy

The posterior atlantooccipital membrane is situated in the upper part of the neck, forming the posterior boundary of the vertebral canal at the level of the atlas. It is continuous with the ligamentum flavum below and the posterior longitudinal ligament above. The membrane is composed of dense fibrous connective tissue, providing stability to the atlanto-occipital joint.

Function

The primary function of the posterior atlantooccipital membrane is to support the head and neck, allowing for a range of movements while maintaining stability. It helps to limit excessive flexion and extension of the head, protecting the spinal cord and vertebral arteries that pass through the foramen magnum.

Clinical Significance

Injuries or abnormalities of the posterior atlantooccipital membrane can lead to instability of the atlanto-occipital joint, which may result in neurological symptoms due to compression of the spinal cord or vertebral arteries. Conditions such as rheumatoid arthritis or trauma can affect this membrane, necessitating medical evaluation and possible intervention.

See Also

• Anterior atlantooccipital membrane
• Atlanto-occipital joint
• Atlas (anatomy)
• Occipital bone
• Ligamentum flavum
• Posterior longitudinal ligament