Atlanto-occipital joint

Atlanto-occipital joint

The Atlanto-occipital joint is a pair of joints that connect the base of the skull and the first vertebra of the spine. It is named for the two bones that it connects: the occipital bone of the skull and the atlas, the first cervical vertebra.

Etymology

The term "atlanto-occipital" is derived from the names of the two bones involved: "atlas" and "occipital". The atlas is named for the Titan Atlas from Greek mythology, who was condemned to hold up the sky for eternity. The occipital bone is named for its location at the back of the skull, from the Latin 'occiput' meaning back of the skull.

Structure

The atlanto-occipital joint is a condyloid joint, which allows for the nodding and side-to-side movements of the head. It is formed by the oval-shaped occipital condyles of the occipital bone, which fit into the concave superior articular facets of the atlas.

Capsule

The joint is enclosed by a joint capsule, which is a thin, fibrous sac that contains the joint and the synovial fluid that lubricates it. The capsule is attached to the margins of the articular surfaces, and its fibres blend with the anterior atlantooccipital membrane and posterior atlantooccipital membrane.

Function

The atlanto-occipital joint allows for the nodding motion of the head, such as when indicating agreement or acknowledgement. It also allows for some side-to-side movement of the head.

Clinical significance

Injuries to the atlanto-occipital joint can be serious and potentially life-threatening, as they can result in damage to the spinal cord. Such injuries can occur as a result of trauma, such as a car accident or fall.

See also

• Atlanto-axial joint
• Cervical vertebrae
• Occipital bone
• Atlas (anatomy)

References

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  Atlanto-occipital joint lateral view

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  Atlanto-occipital joint superior view

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  Atlanto-occipital joint anterior view