C2/C7 (Quiz 2/Test 2) Flashcards
Why is C2 atypical?
-no pre-zygopophyses
-no uncinate processes
-superior epiphysis is buried under the dens
-odontoid process is a unique feature of C2
things that are normal tho:
-has a body
-inferior epiphysis
-shows prominent anterior lipping
-concave AP, slightly posterior lipping
-forms uncovertebral joint with C2 uncinate processes
What are the features of the anterior surface of C2?
-midline ridge up to the dens
-2 lateral weight-bearing concavities (C2 receives weight on L/R superior articular surfaces)
-the weight is “translated” onto the inferior epiphysis and L/R inferior articular surfaces
-the weight also thickens the pedicles per Wolf’s law
-C2 anterior surface also has a transverse ridge that is buried within the superior epiphysis
What is the odontoid process/dens of C2? What are its features?
-“tooth like”
-thick, strong bony process
-covers almost the entire superior epiphysis
-wide, deeply embedded “base”
-narrow, constricted “neck”
-has an anatomical neck between base and head
-has a surgical neck (this is the most common fracture site)
Where does the odontoid process/dens of C2 project?
superiorly and slightly posteriorly
What are the features of the posterior groove of C2?
-its a transverse depression that may show articular facet (produced by transverse ligament pressure)
-has a bulbous “head”
-has an anterior articular facet
-smooth tall oval surface
-covers the entire anterior surface
-slightly convex along both axes
What direction does the posterior groove of C2 face?
test q
anteriorly (this is ironic)
What does the posterior groove of C2 articulate with?
fovea dentalis
The apex of C2 is flat and has a small spikule, which is an attachment for what ligament?
apical ligament
The apex of C2 has a L/R posterolateral hollow surface, which are attachment sites for what ligament?
alar ligament
What does the posterior surface of the apex of C2 show?
basi-vertebral foramen
What are the features of the pedicles of C2?
-thick, strong horizontal cylinders
-has a wide shallow superior pedicle notch
-has a deep inferior pedicle notch that contributes to the 3rd IVF
Where do the pedicles of C2 project?
-posterolaterally and curve posterior
-projects from top half of body
What are the features of C2 superior articular surfaces?
-round or oval, smooth, clear margins
-flat L/R
-convex AP
-thick cartilage
Where do the superior articular surfaces of C2 face?
test q
superolaterally
What do the superior articular surfaces of C2 articulate with?
C1 inferior articular surfaces
What are the superior articular surfaces of C2 supported by?
-mostly the pedicles
-body (medially 1/3 of superior articular surfaces)
-anterior TPs (anterior margin of superior articular surface)
Where do the post-zygopophyses of C2 project?
inferiorly from the pedicles
Where are post-zygopophyses of C2 found and what are their features?
-posterior to the inferior pedicle notch
-supports the inferior articular surfaces
-smooth, round, or oval, and flat
-covers the anteroinferior surface
Where does the post-zygopophyses of C2 face?
anteroinferiorly, slightly laterally
What are the features of the laminae of C2?
-thick, strong vertical bony plates
-thin top edges, thicker bottom edges
-meet and fuse (line of interlaminar fusion) to form the base of the spinous
Where do the laminae of C2 project?
posteromedially from the pedicles
Where does the SP of C2 project?
posteriorly, slightly superior
What are the features of C2 SP?
-prominent bifid tip (palpate below EOP)
-forms strong lever arm for flexion and extension
The anterior false costo TPs of C2 are thin horizontal cylinders of bone that support what?
anterior margins of the superior articular surfaces
Where do the anterior false costo TPs of C2 project?
postero-infero-laterally from the body
Posterior true TPs of C2 are thin horizontal cylinders of bone. Where do the posterior true TPs project?
antero-infero-laterally from the pedicles
The anterior and posterior TPs of C2 meet/fuse and form what?
small sharp distal transverse tubercle
What do the foramina transversaria do in C2?
-the smallest ones contain the vertebral arteries
-they tilt downward (direct the vertebral arteries superolaterally)
-they stabilize the vertebral arteries during C1/C2 rotation
