10/8 Questions Flashcards
(39 cards)
What other joint space does the atlanto-occipital joint communicate with?
the posterior bursa of the median atlanto-axial joint
What is the classic function of the anterior atlanto-occipital ligament?
it brakes or limits extension of the skull over the cervical spine
Ossification of the free margin of the posterior atlanto-occipital ligament results in which atypical bone classification?
accessory bone
What other name may be used to identify a ponticulus posticus?
Kimmerle’s anomaly
What names are given to the opening formed by the ponticulus posticus?
arcuate foramen or retroarticular canal
What is the classic function of the posterior atlanto-occipital ligament?
it brakes or limits axial rotation, flexion, and perhaps lateral bending of the skull on atlas
What amount of flexion-extension is accommodated by the atlanto-occipital joint?
about 25 degrees
What amount of axial rotation is accommodated by the atlanto-occipital joint?
about three to eight degrees one side axial rotation
What amount of lateral bending is accommodated by the atlanto-occipital joint?
about 5 degrees
Which motion is best accommodated by the atlanto-occipital joint?
flexion-extension
Which atlanto-axial joint is identified as a synovial pivot (diarthrosis trochoid)?
the median atlanto-axial joint
Which atlanto-axial joint is identified as a synovial plane (diarthrosis arthrodia)?
the lateral atlanto-axial joint
What are the names given to the synovial joint spaces of the median atlanto-axial joint?
the anterior bursa and the posterior bursa
What is the function of the transverse atlantal ligament?
it is the primary stabilizer 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 radiographic distance between the surfaces of the anterior bursa of the median atlanto-axial joint
The ADI is observed between which surfaces?
the fovea dentis of C1 and the facet for fovea dentis of C2
What is the ADI of children compared with that of adults?
about 4.5 mm in children
a range of 2-3 mm or about 2.5 mm in adults
What are the attachment sites for the accessory atlanto-axial ligament?
the base of the odontoid process and vertebral body of axis to the tubercle for the transverse atlantal ligament on the lateral mass of C1; a superior continuation may attach on the occipital bone just behind that of the alar ligament
What are the degrees of movement facilitated at the atlanto-axial joint?
about 20 degrees flexion-extension
40 degrees one side axial rotation
5 degrees of lateral bending
The occiput-C1-C2 joint complex accounts for what percent of all cervical axial rotation?
about 60%
What ligament attaches to the anterior margin of the foramen magnum and the tip of the odontoid process of C2?
the apical ligament of the dens or the apicodental ligament
What is the embryonic derivative of the apical ligament of the dens or the apicodental ligament?
the notochord
What is the function of the alar ligament?
together they function to resist axial rotation
What forms the cranial continuation of the posterior longitudinal ligament?
the membrana tectoria or tectorial membrane
