The atlantodental interval (ADI) is the horizontal distance between the anterior arch of the atlas and the dens of the axis, used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis.
How do you assess for atlanto-axial instability?
The patient is asked to slowly flex the head performing a slight cervical nod, at the same time the examiner presses posteriorly on the patient’s forehead. A sliding motion of the head in relation to the axis indicates atlantoaxial instability.
What is the atlanto-axial?
The atlantoaxial joint is a type of synovial joint that is classified as a biaxial, pivot joint. This joint resides in the upper part of the neck between the first and second cervical vertebrae, also known as the atlas and axis, respectively.
What is normal ADI?
The ADI is measured from the inferior border of the anterior tubercle of the C1 arch to the Odontoid process (Dens) of C2. The normal width is 1–5 mm for children & 1–3 mm (maximum) in adults. This space may increase in old age as a response to degeneration of the atlantodental joint complex.
What is atlas and Axis?
The atlas and axis vertebrae are the two most superior bones in the vertebral column, and they are part of the seven cervical vertebrae. The atlas is the top-most bone, sitting just below the skull; it is followed by the axis. Together, they support the skull, facilitate neck movement, and protect the spinal cord.
What joint is between C1 and C2?
atlantoaxial joint
The C1 and C2 vertebrae are the first two vertebrae at the top of the cervical spine. Together they form the atlantoaxial joint, which is a pivot joint.
What is the atlanto axial subluxation?
Atlanto-Axial Subluxation/Dislocation Distance between the anterior surface of the dens and the posterior surface of the tubercle of C1 is usually 3 mm or less in adults and 5 mm or less in children This space is called by many names: predentate space, predental space, atlantodental distance
What is the atlantodental interval?
The atlantodental interval (ADI) is the horizontal distance between the anterior arch of the atlas and the dens of the axis, used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis.
What is atlantoaxial instability?
Atlantoaxial Instability. The atlantoaxial joint is an important “transitional zone” in the cervical spine. prone to instability by both degenerative and traumatic processes.
What does atlantoaxial dislocation look like?
Atlantoaxial dislocation. Lateral view of the cervical spine done as a cross-table lateral shows a marked increase in the distance between the anterior surface of the dens and the posterior surface of the C1 tubercle (blue arrow) that measured 14 mm (black line), well in excess of the 3 mm maximum in adults.
