Cervical Spine Biomechanics

Question 1

How many DOF does AO have

Answer 1

3

Question 2

how much flexion and extension does AO have

Answer 2

3.5 flexion, 21 extension

Question 3

Biomechanics of OA flexion

Answer 3

CV occipital condyles roll anteriorly and glide posteriorly

Question 4

Biomechanics of OA Extension

Answer 4

convex occipital condyles roll posteriorly and glide anteriorly

Question 5

OA flexion is limited by

Answer 5

dens

Question 6

OA extension is limited by

Answer 6

tectorial membrane and bony contact

Question 7

OA flexion produced by

Answer 7

longus capitus and rectus capitus anterior

Question 8

OA extension is produced by

Answer 8

RCP major and minor, semispinalis, splenius, and sup oblique

Question 9

How much lateral flexion and rotation does AO joint have

Answer 9

6 lateral, 7 rotation

Question 10

Biomechanics of OA lateral flexion

Why does lateral OA flexion cause CL rotation?

Answer 10

ipsilateral side: rolls ipsilaterally and glides contralaterally

produces contralateral rotation because tightens up contralateral alar ligament

Question 11

biomechanics of OA rotation

Answer 11

ipsilateral side: posterior glide
CL side: anterior glide

Question 12

how many degrees is considered hypermobility in the AO joint for rotation?

Answer 12

more than 8 degrees

Question 13

what limits OA rotation??

Answer 13

Alar ligaments

Question 14

How much flexion and extension does the AA joint have

Answer 14

11.5 flexion
11 extension

Question 15

biomechanics of AA flexion

Answer 15

compression of anterior cartilage
Gap posterior
Atlas move inferior on dens

Question 16

biomechanics of AA extension

Answer 16

compression of posterior cartilage
gap anteriorly
atlas moves superiorly on dens

Question 17

what limits AA flexion

Answer 17

tectorial membrane

Question 18

what limits AA extension

Answer 18

anterior arch on the dens

Question 19

how much rotation does AA have

Answer 19

about 40 degrees or 50% of cervical rotation

Question 20

biomechanics of AA rotation

Answer 20

occurs before rest of cervical region
Atlas pivots around dens
Lateral joint: vertical screwing mechanism, like “telescoping”

(couples with lateral flexion to the opposite side)

Question 21

AA rotation is limited by

Answer 21

alar ligament

Question 22

AA rotation is produced by which muscles?

Answer 22

inferior oblique, RCP major and minor

Question 23

Osteokinematics of superior vertebral body C2-7 for flexion

Answer 23

anterior rock
anterior translation

Question 24

what limits anterior rock/translation of superior vertebral body C2-7 during flexion?

Answer 24

ant rock- extensor mm, PLL, interspinous and ligamentum flavum
ant translation- nuchael lig and disc

Question 25

Arthrokinematics of C2-7 inferior facets (flexion)

Answer 25

inferior facets of the superior vertebrae glide superiorly and anteriorly

Question 26

Arthrokinematics of C2-7 U joint (flexion)

Answer 26

anterior spin

Question 27

When is the volume of the spinal canal greatest?

Answer 27

full flexion

Question 28

where does the greatest amount of cervical flexion occur?

Answer 28

C5-6 (spondylosis and hyperflexion injury related fractures common)

Question 29

Describe osteokinematics C2-7 extension at the sup. vertebral body and what limits these 2 things?

Answer 29

post rock- ant mm, ALL post translartion- disc

Question 30

Arthrokinematics of C2-7 extension

Answer 30

inferior facets of the superior VB glide inferiorly and posteriorly

Question 31

what limits C2-7 extension

Answer 31

joint capsule

Question 32

Arthrokinematics of C2-7 U joint

Answer 32

posterior spin

Question 33

when is the volume of spinal canal least?

Answer 33

in extension

Question 34

most cervical extension happens where?

Answer 34

C5-6

Question 35

Osteokinematics of C2-7 lateral felxion, and # of degrees

Answer 35

ROM 35 degrees sup, VB ipsilateral rock CL translation

Question 36

what is the ipsilateral rock and CL translation of sup vertebral body during C2-7 lateral flexion limited by?

Answer 36

ipsi rock- CL scalenes and intratransverse lig contra translation- disc

Question 37

Arthrokinematics of C2-7 lateral flexion

Answer 37

ipsi facet: glide inferior and posterior contra facet: sup and anterior Ipsi U joint: inferior medial glide contra U joint: supero-lateral glide

Question 38

what limits C2-7 lateral flexion

Answer 38

joint capsule

Question 39

How much C2-7 rotation occurs

Answer 39

45 degrees

Question 40

osteokinematics of C2-7 rotation

Answer 40

superior VB axial rotation coupled with ipsilateral side flexion translation follows side flexion

Question 41

arthrokinematics of C2-7 rotation

Answer 41

Ipsi facet: glides inferior and posterior Contra facet: superior and anterior ipsi U joint: inferior medial contra U joint: superior lateral