vertebral column 1 - part 2 Flashcards
Posterior elements:
- Articular processes
- Spinous process
- Transverse processes
Posterior elements:
Articular processes
Inferior articular processes hook onto the superior articular processes of the
vertebra below:
Depending on - the orientation of the articular facets
Or - the height of the superior articular processes they may resist forward sliding and/or rotation of the upper vertebra
* alignment is diff. in diff. regions
The role of the zygapophysial joints in resisting movements:
Superior articular facets aligned in the coronal plane resist anterior translation of the superior vertebra - in coronal plane resist flx/ext
even more so the more vertical they are.
* Superior articular facets aligned in the sagittal plane resist axial rotation of the superior vertebra
- superior articular processes blocks flx
The role of the zygapophysial joints in resisting movements: cervical c3-7
almost coronal orientation 45˚ to transverse
allows all mvmt
The role of the zygapophysial joints in resisting movements: thoracic
almost coronal orientation
‘tall’ superior articular process
60-800 to transverse (more vertical than Cx)
allows axial rotation and lateral flx
The role of the zygapophysial joints in resisting movements: lumbar
Sagittal plane orientation
vertical
allows flx and ext.
cervical
most mobile in all 3 mvmrs:
flx/ext, lateral flx and axial rotation
cause of alignment of zyg. points, height of vertebrae and disc
thoracic
better for axial rotation
as low vertebral disc height and rib cage
longer spinous processes than lumbar
lumbar
more mid lumbar
The lumbar facet joints allow for significant flexion and extension movement but limits rotation.
Posterior elements:
- Articular processes
Under compression +/- extension weight can be transferred through inferior articular processes to the lamina below
Pars interarticularis
lamina between articular processes
vertebrae dog
Ear = superior articular process Nose = transverse process
Front leg = inferior articular process Neck = pars interarticularis
Body = spinous process
Pars interarticularis fracture:
Inferior articular process impacts lamina below = force transfer through posterior elements Extension!
Muscles attach to the spinous and transverse processes:
Create bending & shearing forces
Fan-shaped trabeculae spanning between the vertebral body and the posterior elements.
* muscles pull on them to move vertebrae so need strong pedicles for force transfer and don’t get breakdown
pedicle
Increased density of compact bone near the base of the pedicles
vertebral ligaments during movement
limit movement - end range mvmt
* posterior 2 COR - when it lengthens = collagen tightens and resist end range flx
sensory feedback
supraspinous lig
- most effective in limitting flx. because has longest MA
- furtherest from axis and vertical collagen alignment
vertebral ligaments
anterior longitudinal ligament posterior longitudinal ligament ligamentum flavum interspinous ligament supraspinous ligament
LIGAMENTUM FLAVUM
paired, thick, segmental, elastic ligaments
Form the:
• posterior wall of the vertebral canal &
• anterior capsule of zygapophyseal joints
longitudinal lig. during mvmt - flx
anterior long. lig = compressed
post. long. lig = stretched
longitudinal lig. during mvmt - ext
post long. lig = slack
anterior. long. lig = stretched
Interspinous ligaments: direction of fibres & shear forces
oblique fibre orientation anterior / inferior
* different layers
from 1 spinous process > nxt spinous processes
resist posterior shear of superior vertebrae
Interspinous ligaments: during flx
combine anterior rotation with anterior translation
- keeps z joints in contact
resist posterior shear of superior vertebra
* during flx, spinous process moves upwards which tightens interspinous fibres and then translate superior vertebrae anteriorly which keeps z joints in contact.
