Unit 3-vertebral column Flashcards
shape of inferior facet of atlas and superior facet of axis
both are close to flat/convex, so allow gliding
lateral flexion of atlantoaxial joint is coupled with______
contralateral rotation
what ligaments are true stabilizers of the AC joint
coracoclavicular ligament complex: conoid and trapezoid
inferior facets of lower cervical vertebrae
face anteriorly and inferiorly
effect of prolonged forward head position
- increase anterior shear
- upper cervical extension
- suboccipital muscles adaptively shorten
limiting factors of VC flexion
posterior longitudinal ligament, posterior annulus fibers, facet joint capsule, extensors
abductors of the shoulder at the GH
deltoid, supraspinatus
upward rotators of the scapula
trapezius and serratus anterior
limiting factors of VC extension
spinous processes, anterior longitudinal ligament facet joint capsule, size of disc
thoracic vertebrae articulation with ribs
costovertebral: demi facet to vertebral body
costotransverse: oval facet to transverse process
dynamic stability of GH joint
- combination of muscle action and passive structures
- gravity
- joint reaction forces and friction
facet joint motion during flexion
up glide
facet joint motion during extension
down glide and posterior glide
facet joint motion during lateral flexion
ipsilateral: down and posterior glide
contralateral: up glide
alar ligaments
from axis (near dens) laterally and superiorly to medial side of occipital condyles and lateral mass of atlas
- stretched in neck flexion
- limits lateral flexion
- prevents distraction of c1 from c2
facets of lower cervical vertebrae
superior: superior and posterior
inferior: inferior and anterior
facet joints of lower cervical vertebrae
relatively lax, restrict lateral flexion and rotation
-oriented at about 45 degrees from frontal and horizontal plane
atlanto-occipital motion
primarily flexion/extension
-flexion: occiput rolls anterior, slides posterior
-extension: occiput rolls posterior, slides anterior
rotation/lateral flexion: limited by joint capsule
atlanto-axial motion
rotation (>50% of total rotation)
- about 45 degrees in each direction, limited by alar ligament
- lateral flexion: coupled with contralateral rotation
- flexion/extension
lower cervical coupled motions: flexion
anterior translation with anterior rotation
lower cervical coupled motions: extension
posterior translation with posterior rotation
lower cervical coupled motions: lateral flexion
coupled with ipsilateral rotation
lower cervical coupled motions: rotation
coupled with ipsilateral lateral flexion
flexion/extension in T1-T6
limited b/c of rib cage, facets in frontal plane, extension limited by ligaments and spinous processes
flexion/extension in T7-T12
facets closer to sagittal plane than in upper thoracic
coupled motion of thoracic vertebra
lateral flexion coupled with rotation
how thoracic rotation affects the ribs
causes distortion of the associated ribs because transverse processes articulate with posterior surface of rib and cartilage can move
–scoliosis
superior facets of lumbar vertebrae
medial and posterior
inferior facets of lumbar vertebrae
lateral and anterior
facet joint of sacral vertebrae
limited anterior shear in frontal plane because of shape
allows flexion/extension in saggital plane, resists rotation
lumbosacral articulation
line parallel to superior aspect of sacrum–increase angle= increase shear force
what causes axial compression of the column
gravity, muscles, ligaments
shear force on the vertebral column
caused by force along the midplane of the disc
primarily in facet joints
secondary: disc (annulus fibrosus)
sacroiliac motion
symmetrical and asymmetrical
symmetrical sacroiliac motion
innominates move together
- nutation: superior portion of sacrum moves anterior and inferior
- counter nutation: superior portion of sacrum moves posterior and inferior
- A/P pevic tilt
asymmetrical sacroiliac motion
innominates move opposite; closed chain
causes pelvic torsion: motion at SI and pubic symphysis
posterior muscles of the VC
capital extensors: suboccipital, spenius capitus and cervicis
levator scap
traps
role of levator scap in VC
compresses the spinal column and causes some posterior shear that can offset anterior shear
lateral muscles of VC
scalenes and SCM; control side to side head movement; low activation needed in normal upright sitting
anterior muscles of VC
longus capitis, longus colli, rectus capitis anterior, rectus capitis lateralis
effect of forward head posture
increased anterior shear, need more levator scap and semispinalis capitis
upper cervical extension, need more supoccipital muscles to pull
muscle synergies in the neck
anterior scalene and levator scap: stability in sagittal plane
longus capitus/colli & upper trap, elevation of scapula