XI. Atlanto-Axial Joint Flashcards
What are the joint surfaces of the median atlanto-axial joint at the anterior bursa?
the fovea dentis of C1 and the facet for fovea dentis of C2
What are the joint surfaces of the median atlanto-axial joint at the posterior bursa?
the groove for the transverse atlantal lig. of C2 and the transverse atlantal lig.
What lig. is formed by the transverse atlantal lig. and its perpendicular extension?
the cruciate lig. or cruciform lig.
What is the function of the transverse atlantal lig.?
it is the primary stablizer of the atlanto-axial joint restricting the distance of C2 from the anterior arch of C1
What is the ADI?
the Atlanto-Dental Interspace, a rodiographic distance between the surfaces of the anterior bursa of the median atlanto-axial joint
What is the ADI of children compared with that of adults?
about 4.5 mm in children; a range of 2-3mm or about 2.5 mm in adults
What are the attachment sites for the accessory atlanto-axial lig.?
the base of the odontoid process and vertebral body of axis to the tubercle for the transverse atlantal lig. on the lateral mass of C1; a superior continuation may attach on the occipital bone just behind that of the alar lig.
What lig. forms the posterior boundary of the spinal canal at the C1/C2 vertebral couple?
the posterior atlanto-axial lig.
What are the degrees of movement facilitated at the atlanto-axial joint?
about 20 degrees flexion - extension, 40 degrees one side axial rotation, and 5 degrees of lateral bending
The occiput C1-C2 joint complex accounts for what percent of all cervical axial rotation?
about 60%
