Cervical Spine Biomechanics Flashcards
How many DOF does AO have
3
how much flexion and extension does AO have
3.5 flexion, 21 extension
Biomechanics of OA flexion
CV occipital condyles roll anteriorly and glide posteriorly
Biomechanics of OA Extension
convex occipital condyles roll posteriorly and glide anteriorly
OA flexion is limited by
dens
OA extension is limited by
tectorial membrane and bony contact
OA flexion produced by
longus capitus and rectus capitus anterior
OA extension is produced by
RCP major and minor, semispinalis, splenius, and sup oblique
How much lateral flexion and rotation does AO joint have
6 lateral, 7 rotation
Biomechanics of OA lateral flexion
Why does lateral OA flexion cause CL rotation?
ipsilateral side: rolls ipsilaterally and glides contralaterally
produces contralateral rotation because tightens up contralateral alar ligament
biomechanics of OA rotation
ipsilateral side: posterior glide
CL side: anterior glide
how many degrees is considered hypermobility in the AO joint for rotation?
more than 8 degrees
what limits OA rotation??
Alar ligaments
How much flexion and extension does the AA joint have
11.5 flexion
11 extension
biomechanics of AA flexion
compression of anterior cartilage
Gap posterior
Atlas move inferior on dens
biomechanics of AA extension
compression of posterior cartilage
gap anteriorly
atlas moves superiorly on dens
what limits AA flexion
tectorial membrane
what limits AA extension
anterior arch on the dens
how much rotation does AA have
about 40 degrees or 50% of cervical rotation
biomechanics of AA rotation
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)
AA rotation is limited by
alar ligament
AA rotation is produced by which muscles?
inferior oblique, RCP major and minor
Osteokinematics of superior vertebral body C2-7 for flexion
anterior rock
anterior translation
what limits anterior rock/translation of superior vertebral body C2-7 during flexion?
ant rock- extensor mm, PLL, interspinous and ligamentum flavum
ant translation- nuchael lig and disc
Arthrokinematics of C2-7 inferior facets (flexion)
inferior facets of the superior vertebrae glide superiorly and anteriorly
Arthrokinematics of C2-7 U joint (flexion)
anterior spin
When is the volume of the spinal canal greatest?
full flexion
where does the greatest amount of cervical flexion occur?
C5-6 (spondylosis and hyperflexion injury related fractures common)
Describe osteokinematics C2-7 extension at the sup. vertebral body
and what limits these 2 things?
post rock- ant mm, ALL
post translartion- disc
Arthrokinematics of C2-7 extension
inferior facets of the superior VB glide inferiorly and posteriorly
what limits C2-7 extension
joint capsule
Arthrokinematics of C2-7 U joint
posterior spin
when is the volume of spinal canal least?
in extension
most cervical extension happens where?
C5-6
Osteokinematics of C2-7 lateral felxion, and # of degrees
ROM 35 degrees
sup, VB ipsilateral rock
CL translation
what is the ipsilateral rock and CL translation of sup vertebral body during C2-7 lateral flexion limited by?
ipsi rock- CL scalenes and intratransverse lig
contra translation- disc
Arthrokinematics of C2-7 lateral flexion
ipsi facet: glide inferior and posterior
contra facet: sup and anterior
Ipsi U joint: inferior medial glide
contra U joint: supero-lateral glide
what limits C2-7 lateral flexion
joint capsule
How much C2-7 rotation occurs
45 degrees
osteokinematics of C2-7 rotation
superior VB
axial rotation
coupled with ipsilateral side flexion
translation follows side flexion
arthrokinematics of C2-7 rotation
Ipsi facet: glides inferior and posterior
Contra facet: superior and anterior
ipsi U joint: inferior medial
contra U joint: superior lateral
