Cervical Spine Biomechanics

Question 1

Which joint compose the upper C/S?

Answer 1

AO (C1-occiput) and AA (C1-C2).

Question 2

Which joint in the spine does not have an IVD?

Answer 2

AA (C1-C2).

Question 3

Describe the pain referral pattern of vertebral artery insufficiency.

Answer 3

Posterior cervical spine region, one sided (ipsilateral), lateral to spinous processes.

Question 4

Describe the pain referral pattern of internal carotid artery dissection.

Answer 4

Posterolateral cervical spine region and temple (ipsilateral).

Question 5

Where does the dens fit into C1?

Answer 5

Anterior tubercle region of vertebral canal, stabilized by transverse ligament.

Question 6

What type of joint is AO and what are the DOF?

Answer 6

Modified ovoid, bicondylar.

i) flex/ext.
ii) side flexion w/ conjunct contralateral rotation.

Question 7

Describe the congruency of the AO joint.

Answer 7

The occiput is convex and C1 articulating facets are concave (slightly). C1 articulating processes face superiorly and medially. Note: largest TP of C/S at C1.

Question 8

Describe the osteokinematics an arthrokinematics of AO flexion.

Answer 8

i) Anterior rotation (5-10’)
ii) Posterior translation

i) anterior roll, posterior glide of occiput.

Question 9

Describe the osteokinematics and arthrokinematics of AO extension.

Answer 9

i) Posterior rotation (10-20’)
ii) anterior translation

i) posterior roll, anterior glide of occiput.

Question 10

Describe the osteokinematics and arthrokinematics of AO right side flexion.

Answer 10

i) R side tilt
ii) L rotation

i) R articular facet slides anteromedially
ii) L articular facet slides posterolaterally.

Question 11

What type of joint is AA and what are the degrees of freedom?

Answer 11

i) sellar

i) flex/ext
ii) rotation with conjunct contralateral side flexion (75% of total rotation.

Question 12

What is the axis of rotation about the AA joint?

Answer 12

Dens.

Question 13

Describe the congruency of the AA joint.

Answer 13

Generally flat and in line with horizontal plane.

Question 14

Describe the osteokinematics and arthrokinematics of flexion at the AA joint.

Answer 14

i) anterior rotation (15’), atlas tilts anteriorly

ii) inferior slide of atlas on dens.

Question 15

Describe the osteokinematics and arthrokinematics of extension at the AA joint.

Answer 15

i) posterior rotation

ii) superior slides of atlas on dens

Question 16

Describe the osteokinematics of side flexion at the AA joint.

Answer 16

i) horizontal rotation (35-45’)
ii) paired w/ contralateral side flexion:
- R rotation is limited by L alar ligament causing contralateral coupling of L side flexion.

Question 17

Describe the arthrokinematics of side flexion at the AA joint.

Answer 17

i) Central joint: horizontal twist about dens
ii) Ipsilateral Lateral joint: posterior slide.
iii) Contralateral lateral joint: anterior slide.

Question 18

What structures limit AA rotation?

Answer 18

i) Alar ligament (contralateral aspect)

ii) AA joint capsule

Question 19

What are the functions of the uncinate processes?

Answer 19

i) limit side flexion

ii) limit posterior slides

Question 20

Describe the process of aging uncovertebral joints.

Answer 20

They continue to grow with age which eventually pinches the posterior aspect of the disc resulting in a horizontal cleft. They also cause the disc to move superiorly resulting in stenosis of the IVF - this is furthered in the case of osteophyte formation on the uncovertebral processes. This begins around the age of 15.

Question 21

Describe the orientation of facet joints from C2-C7.

Answer 21

Sloped on a 45’ angle from moving inferiorly and posteriorly from an anterior origin. This allows for movement in all three planes.

Question 22

What is the resting position of the C/S facet joint?

Answer 22

Slight flexion.

Question 23

What is the close packed position of the C/S facet joint?

Answer 23

Full extension.

Question 24

What is the capsular pattern of the C/S facets?

Answer 24

SF = rot’n > extension.

Question 25

What are the components of a lower C/S joint?

Answer 25

i) 2 facet joints ii) 2 uncovertebral joints iii) 1 central IVD

Question 26

Describe the osteo and arthro kinematics of flexion in the lower C/S?

Answer 26

i) anterior rotation (35'), anterior translation (upper segment) ii) anterior and superior glide (upper segment)

Question 27

Describe the osteo and arthro kinematics of extension in the lower C/S.

Answer 27

i) posterior rotation (55-60'), posterior translation | ii) posterior and inferior glide

Question 28

Describe the osteo and arthro kinematics of side flexion in the lower C/S.

Answer 28

i) Rotates ipsilateral direction (35') ii) Ipsi facet: inferior, medial, posterior (IMP) iii) Contra facet: superior, anterior, lateral (SAL)

Question 29

Describe the osteo and arthro kinematics of rotation in the lower C/S.

Answer 29

i) rotation (45'), contralateral translation, ipsilateral side flexion. ii) Ipsilateral facet: IMP iii) Contralateral facet: SAL