2 - regional variation in the vertebral column Flashcards
only mammals have
lumbar vertebrae
lumbar spine facilitates
flexion and extension
thoracic spine facilitates
rotation
the motion segment
the functional unit of the spine
2 vertebrae plus the joints in between
have anterior and posterior components
anterior components of the motion segment
passive, load bearing
- adjacent vertebral bodies
- anterior and posterior longitudinal ligaments
- intervertebral disks - symphysis joints
posterior componetns
dynamic, control of motion, levers for muscles
most of these bony features are derived from the neural arch element
the intervertebral disks joint
type of symphysis joint
function of the intervertebral disk
primarily transmits loads, but also allows/limits movements
4 components of the intervertebral disk
nucelus contained within an envelope
- annulus fibrosus
- nucleus polposus
- cartilage end plate
- annular apophysis
apophysis is called epiphysis until
it has finished gorwing
annulus fibrosus
many lamellae (layers) of fibrocartilage - outer layers attach directly to annular apophysis inner layers attach into cartilage end plate and encircle nucleus polposus
mechanism of the intervertebral disks
pressure in the nucelus polposus is contained by tensile strength of the envelope, which keeps vertebrae apart and able to move
problems with the intervertebral disks
weakness in the envelope may allow the nucleus polposus to escape or cause bulging og the annulus fibrosis that presses on other sturctures
nucleus polposus contains
collagen fibrils, proteoglycans and hyaluronic acid
- mix is very hydrophillic
- water is retained - forms a gel that is 80% water
water in the IVD during load bearing activity
water gets squeezzed out during load bearing activities
- nuclear water content replenished during horizontal rest periods via diffuson from end plate cartilage
height in the morning vs evening
taller in the morning
with aging, the nucleus is gradually replaced with
fibrous tissue
- notochord cells start degenerating at 6 months gestation
zygapophysial joints
control direction of spinal motion
disc-facet angle
orientation of the disk and the orientation of the facet
interfacet angles
orientation of z joints in one motion segment
facet set on the arc of a circle
tangential, allows rotation
if there are facets for ribs
thoracic
if there are transverse foramina
cervical
sacral are
fused
which regions have a primary curve
thoracic and sacral
which regions have a kyphosis curve
thoracic and sacral
which regions have secondary curve
cervical and lumbar
which regions have lordosis
cervical and lumbar
