Cervical Spine Biodynamics
The following animations were selected for use in the X-ray Analysis 314 course. They are intended to aid the student in understanding the subtle motions that occur at the joints of the cervical spine during normal bio-dynamics.
These animations were selected from a larger body of work done originally at Life College by Dr. Ed Owens. Those animations can now be found here: http://w3.palmer.edu/owens/ANIM/fliclist.html
Click on the Big or Small AVI or MOV link to display an animation in your browser's media viewer. AVI files work best with MS-Windows media player, while MOV files work with the Quick Player on Apple MacIntosh or MS-Windows Computers. Use the slide bar at the bottom of each animation to move the animation slowly through its range of motion. Viewing the animations in “minimized” form will help to decrease motion distortion during slow motion viewing.
|
|
Cardinal Global Motions
|
Files
|
|
|
Model overview: A view of the whole cervical spine model spinning. The mouth opens to permit viewing of the C1-C2 segment from the Anterior. |
|
|
|
Cervical Flexion/Extension: As the head and hard palate move into flexion (nose down toward the floor) notice how the atlas follows the head and moves into an inferior position. As the head and hard palate move into extension (nose up toward the ceiling) notice how the atlas follows the head and moves into a superior position. |
|
|
|
Cervical Rotation: As the head turns to the left, notice the left lateral mass rotate posterior (back toward you) and the right lateral mass rotates anterior (forward away from you). Notice the posterior tubercle of C1 rotate to the right, followed by the spinouses of C2 through C7 in a “Flag” effect with C7 staying on the visual midline of the neural canal. Also, notice how the vertebral bodies swing toward the side of head rotation as the spinouses swing to the side opposite head rotation. Observe the facets dropping slightly PI on the side of head rotation as the facets on the opposite side ride slightly AS. Notice the subtle concavity of the cervical spine on the side of head rotation and convexity on the opposite side. |
|
|
|
Cervical Lateral flexion: Lateral flexion is another term for head tilt. Notice that the same bio-dynamics occur with head tilt as occur with head rotation. As the head tilts to the left, you can see the atlas rotate slightly posterior on the side of head tilt and anterior on the side opposite head tilt. C1 posterior tubercle swings to the right, followed by the spinouses of C2-C7 in a “Stair Step” effect with C7 spinous staying on the visual midline. The facets on the left side drop PI as the facets on the right side ride AS. This causes an obvious concavity of the cervical spine on the left and convexity on the right. |
|
|
|
Cervical Curve Pattern (lateral view): Observe the x-ray animation of the cervical spine change from a slightly hyperlordotic curve, back through normal to hypolordotic to military to kyphotic. Notice that C2 through C7 must all move PI in order to straighten the cervical curve. This is normal bio-dymanics for a hypolordotic curve. If you were looking for individual vertebral misalignments, you would look to the segment or segments that stand out as being the most PI. |
|
|
Occipito-Atlantal Motion
|
Files
|
|
|
Lateral
Flexion: Observe the motion of occiput on atlas in “Pure
Motion”. Notice that the condyle on
the side of head tilt will rock medially on atlas. At the same time, atlas will rock laterally on the condyle
toward the side of head tilt. This
“shearing” motion of occiput and atlas lengthens the A/O joint on the side of
head tilt. (However, the lateral motion of atlas is not visible in this
animation clip.) |
|
|
Atlanto-Axial Joint
|
Files
|
|
|
C1-C2 Flexion/extension: Observe the criteria for atlas
superiority and inferiority as C1 changes position in this lateral view. Notice the changes that occur at the ADI
space. Observe the changes that occur
between the posterior tubercle of C1and the spinous of C2.
|
|
|
|
An x-ray
view of Flexion/Extension : Observe
the same criteria for atlas superiority and inferiority in an x-ray
view. |
|
|
|
C1-C2
Rotation (A
top view ): Observe the rotation of atlas
as seen on a Base Posterior or Vertex view.
|
|
|
|
C1-C2 Rotation (a posterior view): Observe the rotation of atlas as seen on an APOM or Nasium view. Notice the internal margin of the lateral mass become wider (more surface area visible) on the side of anterior atlas rotation. Also notice the lateral inferior tip of the lateral mass (showing beneath the posterior arch) become smaller (less visible) on the side of anterior atlas rotation. Review your notes for atlas rotation as seen on the APOM view as you view this animation clip. Identify as many of the criteria as you can. |
|
|
C2-C3 Motion Segment
|
Files
|
|
|
C2-C3
lateral flexion: Observe the normal
bio-dynamics of C2 as seen on an APOM or Nasium view. The vertebral body will swing
toward the side of head tilt, while the spinous swings to the opposite
side. Notice the inferior articular
process of C2 drop PI on the side of C2 body rotation, while the opposite
side rides AS. Remember that the
normal bio-dynamics of C2 and the lower cervical segments will be the same in
head rotation as in head tilt. |
