Vertebral Column I Flashcards
how many vertebrae and intervertebral discs are there?
24 mobile vertebrae, 23 intervertebral discs (no disc between C1+2 bc C1 has no intervertebral disc)
functions of the vertebral column? and how do these functions vary in different roles?
protection, weight-bearing/force transmission, mobility. different roles: cervical carries head so doesn’t have large weight bearing role compared to what’s required in the lumbar region, cervical is more moblie to move special sense organs around and to see environment, as you progress down the VC you have greater weight bearing role
describe the vertebral column motion segment
the superior vertebra moves on the inferior vertebrae
name the movements of the vertebral motion segments
3 rotations: coronal plane rotation L and R, sagittal plane tilt (rotates) anterior/posterior, vertical axis axial rotation
3 translations: coronal plane translation L and R, sagittal plane translation anterior/posterior, vertical axis translation extract/compress
describe features of a cervical vertebrae.
v body size? foramen? spinous process? articular facet? any other features?
small v body, lateral/unconvertebral lips on the body, large vertebral foramen, transverse foramen for vertebral artery, anterior and posterior tubercles, bifid spinous process, articular facets 45 degrees to the transverse plane
describe features of a thoracic vertebrae
v body size? foramen? spinous process? articular facet? any other features?
medium v body, wedge shape- anterior v body height < posterior, small round vertebral body, articular demifacets on body articulate w/ribs, articular facets on transverse process for ribs, long downward pointing spinous process, articular facet almost in coronal plane
describe features of a lumbar vertebrae
v body size? foramen? spinous process? articular facet? any other features?
large v body for weight bearing, flat superior/inferior vertebral body, small triangular vertebral body, thick blunt spinous process, mammillary processes, articular facets in the sagittal plane
why does the vertebral body have both horizontal and vertical struts
vertical struts are thicker for weight bearing but are supported by horizontal struts
what is nucleus pulposus?
up to 90% water (incompressible) but is thickened by proteoglycans and collagen
what is annulus fibrosus?
10-20 concentric layers, all fibres in 1 layer = same orientation and opposite to adjacent layer, collagen I fibres to resist tension and encircles NP around and up and over
describe the role of intervertebral disc in weight bearing
A. NP= incompressible, vertical compression of the NP decreases vertical height, expands radially and exerts pressure on the annulus fibres
B. annular fibres resist tension and exert pressure back onto NP
C. NP and AF share the pressure and the pressure is exerted onto the vertebral endplates
D. transmits load to inferior vertebrae
how could dysfunction in the intervertebral disc occur during weight bearing
dysfunction occurs when the NP dries out and has less volume OR stretching/tearing of the AF occurs
describe the role of the intervertebral disc in facilitating movement
by separating the 2 surfaces by an intervertebral disc it maintains the ideal flat weight bearing component and distributing the force to decrease stress and so that the superior vertebrae can undergo angular rocking tilt before impacting the inferior vertebrae (the greater amount of seperation = greater amount of movement)
what are the posterior elements and what are their functions
lamina, articular processes, spinous process, transverse processes. functions: muscle and ligament attachments, provide stability, guide movement
what is the role of the zygapophyseal joints in resisting movement
inferior articular processes hook onto the superior articular processes of the vertebrae 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 vertebrae
in relation to the zygapophyseal joint, what do the superior articular facets aligned in the coronal plane resist?
resists anterior translation of the superior vertebrae even more so the more vertical they are (block flexion)
in relation to the zygapophyseal joint, what do the superior articular facets aligned in the sagittal plane resist?
resists axial rotation of the superior vertebrae (allows F-E, block rotation)
in the cervical region, what movements does the zygapophyseal joint allow?
all movements
in the thoracic region, what movements does the zygapophyseal joint allow?
allows axial rotation and lateral flexion
in the lumbar region, what movements does the zygapophyseal joint allow?
flexion - extension
why are the posterior elements not good at weight bearing and what is the possible injury
activities (e.g. gymnastics, ballet) where you land in extension combined with rotation (particularly load one side) instead of transferring force through your anterior elements (that are already efficient at it), you are transferring force from your inferior articular process down into your lamina between the superior and inferior articular process = par interarticularis
cause a par interarticularis fracture
what region is most exposed to pars interarticularis and why?
LUMBAR bc you are already in lordosis (partly extended in some degree) and posterior tilt (L4 and L5 main area of pars interarticularis
what is the role of the intervertebral disc in resisting movement?
collagen fibres in the annulus fibrosus resist tension
what is the anterior longitudinal ligament connected to?
connected to anterior vertebral bodies and anterior intervertebral discs
what is the posterior longitudinal ligament connected to?
connected to posterior vertebral bodies and intervertebral discs (on the anterior aspects of the vertebral canal)
where is the ligamentum flavum located?
between adjacent lamina & forms the posterior wall of the vertebral canal and anterior capsule of z joints
where is the interspinous ligament located?
between adjacent spinous process
where is the supraspinous ligament located?
attaches posterior aspects of spinous processes
what ligaments provide resistance to flexion?
PLL, LF, ISL, SSL
what ligaments provide resistance to extension?
ALL (anterior longitudal ligament)
