Cervical Spine Biomechanics Flashcards
Which joint compose the upper C/S?
AO (C1-occiput) and AA (C1-C2).
Which joint in the spine does not have an IVD?
AA (C1-C2).
Describe the pain referral pattern of vertebral artery insufficiency.
Posterior cervical spine region, one sided (ipsilateral), lateral to spinous processes.
Describe the pain referral pattern of internal carotid artery dissection.
Posterolateral cervical spine region and temple (ipsilateral).
Where does the dens fit into C1?
Anterior tubercle region of vertebral canal, stabilized by transverse ligament.
What type of joint is AO and what are the DOF?
Modified ovoid, bicondylar.
i) flex/ext.
ii) side flexion w/ conjunct contralateral rotation.
Describe the congruency of the AO joint.
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.
Describe the osteokinematics an arthrokinematics of AO flexion.
i) Anterior rotation (5-10’)
ii) Posterior translation
i) anterior roll, posterior glide of occiput.
Describe the osteokinematics and arthrokinematics of AO extension.
i) Posterior rotation (10-20’)
ii) anterior translation
i) posterior roll, anterior glide of occiput.
Describe the osteokinematics and arthrokinematics of AO right side flexion.
i) R side tilt
ii) L rotation
i) R articular facet slides anteromedially
ii) L articular facet slides posterolaterally.
What type of joint is AA and what are the degrees of freedom?
i) sellar
i) flex/ext
ii) rotation with conjunct contralateral side flexion (75% of total rotation.
What is the axis of rotation about the AA joint?
Dens.
Describe the congruency of the AA joint.
Generally flat and in line with horizontal plane.
Describe the osteokinematics and arthrokinematics of flexion at the AA joint.
i) anterior rotation (15’), atlas tilts anteriorly
ii) inferior slide of atlas on dens.
Describe the osteokinematics and arthrokinematics of extension at the AA joint.
i) posterior rotation
ii) superior slides of atlas on dens
Describe the osteokinematics of side flexion at the AA joint.
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.
Describe the arthrokinematics of side flexion at the AA joint.
i) Central joint: horizontal twist about dens
ii) Ipsilateral Lateral joint: posterior slide.
iii) Contralateral lateral joint: anterior slide.
What structures limit AA rotation?
i) Alar ligament (contralateral aspect)
ii) AA joint capsule
What are the functions of the uncinate processes?
i) limit side flexion
ii) limit posterior slides
Describe the process of aging uncovertebral joints.
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.
Describe the orientation of facet joints from C2-C7.
Sloped on a 45’ angle from moving inferiorly and posteriorly from an anterior origin. This allows for movement in all three planes.
What is the resting position of the C/S facet joint?
Slight flexion.
What is the close packed position of the C/S facet joint?
Full extension.
What is the capsular pattern of the C/S facets?
SF = rot’n > extension.
What are the components of a lower C/S joint?
i) 2 facet joints
ii) 2 uncovertebral joints
iii) 1 central IVD
Describe the osteo and arthro kinematics of flexion in the lower C/S?
i) anterior rotation (35’), anterior translation (upper segment)
ii) anterior and superior glide (upper segment)
Describe the osteo and arthro kinematics of extension in the lower C/S.
i) posterior rotation (55-60’), posterior translation
ii) posterior and inferior glide
Describe the osteo and arthro kinematics of side flexion in the lower C/S.
i) Rotates ipsilateral direction (35’)
ii) Ipsi facet: inferior, medial, posterior (IMP)
iii) Contra facet: superior, anterior, lateral (SAL)
Describe the osteo and arthro kinematics of rotation in the lower C/S.
i) rotation (45’), contralateral translation, ipsilateral side flexion.
ii) Ipsilateral facet: IMP
iii) Contralateral facet: SAL