What is atlanto occipital dissociation?

Introduction: Atlanto-occipital dissociation (AOD) is a rare and unstable injury of the craniocervical junction, associated with very high morbidity and mortality. The most common cause of this injury is high energy trauma with hyperextension of the cranium, such as car accidents.

What causes atlanto occipital dislocation?

Atlanto-occipital dislocation (AOD) is a devastating condition that frequently results in prehospital cardiorespiratory arrest and accounts for 15% of fatal spinal trauma. Atlanto-occipital dislocation occurs 5 times more commonly in children than adults, and is believed to be caused by hyperextension.

What is the joint between occipital and atlas?

The atlanto-occipital joint (articulation between the atlas and the occipital bone; Capsula articularis atlantooccipitalis) consists of a pair of condyloid joints. The atlanto-occipital joint is a synovial joint….

Atlanto-occipital joint
FMA	24939
Anatomical terminology

Can you dislocate your head from your spine?

AOD, also known as internal decapitation or orthopedic decapitation, describes a rare medical condition in which the skull separates from the spinal column during severe head injury.

What movement does the atlanto-occipital joint allow?

flexion-extension
The principal movement at the atlantooccipital joint is flexion-extension. This movement permits nodding of the head, as seen when indicating approval (the “yes” movement).

What does occipital dislocation mean?

Atlanto-occipital dislocation involves complete disruption of all ligamentous relationships between the occiput and the atlas. Death usually occurs immediately from stretching of the brainstem, which causes respiratory arrest. Radiographically, disassociation between the base of the occiput and the arch of C1 is seen.

What is occipital condyles?

The occipital condyles are two large protuberances on the undersurface of the occipital bone, located besides the front half of the foramen magnum. It forms the connection between the skull and the vertebral coloumn.

What movement does the atlanto occipital joint allow?

Can you survive a dislocated neck?

It is possible for a human to survive such an injury; however, 70% of cases result in immediate death. It should not be confused with atlanto-axial dislocation, which describes ligamentous separation between the first and second cervical vertebra.

What does the occipital condyle do?

The occipital bone is an anteriorly concave bone that forms the base of the cranium. The occipital condyles are paired kidney-shaped structures that form the base of the occipital bone and are the structural bases for the articulation of the skull with the cervical spine.

What are the two occipital condyles?

What causes atlanto-occipital traumatic dissociation ( AOD )?

Atlanto-Occipital Dissociation. Atlanto-occipital dissociation (AOD) results from high-energy trauma including from motor vehicle collisions. It is associated with high mortality rates due to brainstem and vascular lesions. It is seen in up to one-third of high-velocity motor vehicle injuries (30–32).

Is the atlanto-occipital dislocation a fatal condition?

Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition.

What causes instability in the atlanto-occipital joint?

The tectorial membrane and alar ligaments provide most of the stability to the atlanto-occipital joint, and injury to these ligaments results in instability due to low inherent osseous stability 3. The Traynelis classification describes injuries according to the displacement of the occipital condyles relative to the atlas.

Where are the lateral masses of the atlanto-occipital joint?

The lateral masses articulate superiorly with the occipital condyles and inferiorly with C2, forming the atlanto-occipital and atlantoaxial joints, respectively. The superior aspect of the lateral masses of C1 contains a groove that allows passage of the vertebral artery before it enters the foramen magnum ( 4 ).