Atlanto-Occipital & Atlanto-Axial & Occipito-Axial Joints

Question 1

classification of the atlanto-occipital joint

Answer 1

synovial (diarthrosis) ellipsoidal

Question 2

other joint space that the atlanto-occipital joint will communicate with

Answer 2

posterior bursa of the median atlanto-axial joint

Question 3

classic function of the anterior atlanto-occipital ligament

Answer 3

brakes or limits “extension” of the skull over the cervical spine

Question 4

ossification of the free margin of the posterior atlanto-occipital ligament results in which atypical bone classification

Answer 4

accessory bone

Question 5

other name that may be used to ID a ponticulus posticus

Answer 5

Kimmerle’s anomaly

Question 6

names given to the opening formed by the ponticulus posticus

Answer 6

arcuate foramen or retroarticular canal

Question 7

classic function of the posterior atlanto-occipital joint

Answer 7

brakes or limits axial rotation, flexion, and perhaps lateral bending of the skull on atlas

Question 8

amount of flexion-extension that is accommodated by the atlanto-occipital joint

Answer 8

~25*

Question 9

amount of axial rotation that is accommodated by the atlanto-occipital joint

Answer 9

~3-8* one side axial rotation

Question 10

amount of lateral bending accommodated by the atlanto-occipital joint

Answer 10

~5*

Question 11

motion is best accommodated by the atlanto-occipital joint

Answer 11

flexion-extension

Question 12

which atlanto-axial joint is ID’ed as a synovial plane

Answer 12

lateral atlanto-axial joint

Question 13

which atlanto-axial joint is ID’ed as a synovial pivot

Answer 13

median atlanto-axial joint

Question 14

names given to the synovial joint spaces of the median atlanto-axial joint

Answer 14

anterior bursa and the posterior bursa

Question 15

function of the transverse atlantal ligament

Answer 15

it is the primary stabalizer of the atlanto-axial joint restricting the distance of C2 from the anterior arch of C1

Question 16

what is ADI

Answer 16

Atlanto-Dental Interspace, a radiographic distance between the surfaces of the anterior bursa of the median atlanto-axial joint

Question 17

ADI is observed between which surfaces

Answer 17

fovea dentis of C1 and the facet for fovea dentis of C2

Question 18

ADI of children vs adults

Answer 18

children = 4.5 mm
adults = 2-3 mm or about 2.5 mm

Question 19

attachment sites for the accessory atlanto-axial ligament

Answer 19

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

Question 20

degrees of movement facilitated at the atlanto-axial joint

Answer 20

20* flexion-extension
40* one side axial rotation
5*lateral bending

Question 21

occiput-C1-C2 joint complex accounts for what percent of all cervical axial rotation

Answer 21

~60%

Question 22

ligament that attaches to the anterior margin of the foramen magnum and the tip of the odontoid process of C2

Answer 22

apical ligament of the dens or the apicodental ligament

Question 23

the embryonic derivative of the apical ligament of the dens or the apicodental ligament

Answer 23

notochord

Question 24

function of the alar ligament

Answer 24

together they function to resist axial rotation

Question 25

forms the cranial continuation of the PLL

Answer 25

membrana tectoria or tectorial membrane

Question 26

attachement sites for the superficial layer of the membrana tectoria

Answer 26

posterior part of the inferior epiphyseal rim and vertebral body of C2 to the capsular ligament of the atlanto-occipital joint and cranial dura of the posterior cranial fossa

Question 27

list, in order, ligaments in the midsagittal plane from the dura mater at the level of the medulla oblongata to the anterior bursa of the median atlanto-axial joint

Answer 27

membrana tectoria

cruciate ligament

capsular ligament of the posterior bursa of the median atlanto-axial joint

apical ligament of the dens

Question 28

for cervical spine below C2, what is the range of flexion-extension

Answer 28

~90* or 18* per couple

Question 29

for cervical spine below C2, what is the range of one side lateral bending

Answer 29

~50* or 10* per couple

Question 30

for cervical spine below C2, what is the range one side axial rotation

Answer 30

~33* or 6* per couple