Cervical Spine Anatomy/Biomechanics Flashcards
What comprises the Upper C-Spine?
Occiput, C1 (atlas), and C2 (axis)
Gimme some facts about C1 vertebrae
Mobility for flexion and extension
Biconvex facet shape
Occipital condyles sit in the superior articular facets
And some facts about C2?
Major upper cervical stabilizer
Uncovertebral joint
The dens sits infront of the brainstem, which can be bad news bears if the ligaments get damaged
What positions can compromise the vertebral artery?
End range c-spine rotation, especially combined with extension and sidebend
Transverse Ligament. GO!
C2 to occiput, covers the dens
“Cruciate”
Maintains integrity of dens to the anterior arch of C1
If it tears/becomes lax, then the dens may press into the brainstem/spinal cord
Alar Ligament
Helps stabilize occiput on C2.
Limits rotation of median atlanto-axial joint
Name the Special Tests for the Transverse and Alar Ligaments
Transverse: Sharp-Pursar (seated), transverse (supine)
Alar: Alar Ligament Stress Test (check rotation AND sidebending)
Describe the biomechanics that occur during flexion and extension
Anterior translation during extension greater at O-C1 than C1-C2
Translational movement in sagittal plane
C1 translates inferiorly relative to C2 and inferiorly relative to occiput. Greatest at C1-2
Occiput slides anterior and medial on C1 in extension
Flexion: posterior and lateral
Rotation Biomechanics
Greater amount of rotation at C1-2 than O-C1.
Rotational movement in a transverse plane
Lateral Flexion Biomechanics
Rotational movement in frontal plane
Both joints exhibit ipsilateral axial rotation
Greater at C1-2
Occiput slides anterior and medial on atlas
Coupling of C1-2 axial rotation and O-C1 lateral flexion
Axial rotation of the head to the LEFT results in a lateral flexion to the RIGHT
Caused by tightening of the alar ligaments
Coupling between O-C1 lateral flexion and axial rotation C1-2
Lateral flexion of the head to the RIGHT DOES NOT result in axial rotation to the LEFT
Coupling between axial rotation C1-2 and lateral translation O-C1-C2
Axial rotation of head to the LEFT results in translation of O-C1 to the LEFT and translation of C1-2 to the LEFT
Caused by ligamentous tension
Coupling between flexion/extension and posterior/anterior translation between O-C1
From flexion to extension in the O-C1 joint, the occipital condyles translate anteriorly in relation to the atlas
Flexing O-C1 will bring C1-2 posteriorly
Coupling between axial rotation C1-2 and longitudinal translation O-C1-C2
Axial rotation of the head from neutral causes the atlas to drop vertically in relation to the axis
Caused by morphology of the facet joints
Where do the occipital condyles go during flexion and extension?
Flexion: Condyles move posterior and lateral
Extension: Condyles move anterior and medial
When doing the Sharp-Purser Test, do you push the head anteriorly or posteriorly?
Don’t push that shit anteriorly! We don’t want to push the brainstem on the dens now do we?
Describe the facets in the lower cervical spine
More medial to lateral
At a 45 degree angle
Role in flexion, extension, sidebend, rotation
Uncovertebral Joints
Uncinate processes grow upwards from the superior aspect to each lateral vertebral margin towards the vertebral body above
Counters motion into sidebending
Facet joints are behind the uncovertebral joints
Do not have synovial fluid, but do have interstitial fluid
Highly vascularized and bleed extensively during trauma (whiplash)
C-Spine Disc Lesions
Less common in the cervical than lumbar
Fissuring- upper C spine loses nucleus
Common source of local pain, referred pain into shoulder and scapula, and headaches
Trauma (whiplash): crush and traction injuries
Cloward areas
What happens in hyperflexion injuries?
Annular fibers are pulled apart and often rupture off the bone (avulsion)
What are the referral patterns of the following:
C2
C3,4,5,6
C5, C6, C7
C2: Only disc that refers pain superiorly into the head, commonly causes headaches
C3,4,5,6: Cloward areas, refer to the thoracic spine between the scapulas
C5,6,7: Lower motion segments, refer into the UE and usually proximal to the elbow.
Describe the curvature in the lower cervical spine
Large lordotic curve in the lower c-spine, reversal of this in the upper c-spine
Full upper cervical flexion is not possible without lower c-spine extension
Lower C-spine biomechanics
In extension, superior vertebra in a motion segment tilts and slides back, reverse occurs in flexion
Superior segment moves on the interior segment
Posterior and inferior glide into extension
Anterior and superior glide into flexion
Patterns of cervical spine movements
Lateral flexion results in coupled ipsilateral rotation at each of the cervical motion segments
Rotation and sidebending are coupled together
Swimmer asymmetries
If a swimmer only breathes to one side, they may have asymmetries in sidebend and rotation
