movements Flashcards
occiput-atlas x-axis rotation range?
14-35 degrees
occiput-atlas y-axis rotation range?
axial- 4-8 degrees each side
occiput-atlas z-axis rotation range?
cadavers- 4-11 degrees
atlas-axis x-axis rotation range?
biconvexity combined= 20 degrees
C1-C2 y axis rotation range?
43 +/- 5 degrees; lots of Y rotation at C2
where does over 50% of the rotation of the neck happen?
C1-C2 y-axis rotation
what structure is displaced with y-axis rotation?
intraarticular meniscoids
what is the range of C1-C2 z-axis lat bend?
limited to 5 degrees- alar ligaments
what is couple with C1-C2 y-axis rotation?
y-translation
what is the C1-C2 z translation?
very little; C1 ring around dens
what is the C1-C2 x translation?
CONTROVERSIAL; only apparent; Panjabi/White
what are the coupled motions involved with C1-C2? (not natural)
axial- longitudinal
lateral- sagittal
+x rot. coupled with?
+ z translation
- x rot. coupled with?
- z translation
+ z rot. is coupled with?
- y rot.
- z rot. is coupled with?
+ y rot.
where are the steepest cervical arches?
C6-7
more translation in cervicals takes place where?
upper cervicals
uncinate processes guide what coupled motion?
lateral flexion with axial rotation
with compressive load, which structure is first to fail?
vertebral end plate
what is the degree of y-axis rotation of the thoracic spine?
20 degrees
what is the thoracic facet orientation from the horizontal plane?
60 degrees
primary movement of thoracics?
lat bending coupled with axial rotation
thoracic flex/ext is combined with?
+/- z translation
what increases y axis stability in the thoracics?
rib cage
L1-L4 facets limit?
axial/y axis rotation
L5-S1 facets limit?
z translation
axial rotation in lumbar is limited due to?
sagittal facet orientation
