Intervertebral Disc Flashcards
What is the number of true intervertebral discs identified in the adult?
twenty-three
In the adult, which vertebral levels will demonstrate a true intervertebral disc?
those between C2 and S1 inclusive
What is the intervertebral disc histologically composed of?
cells, collagen fibers, and a hydrated proteoglycan gel
What is the cervical nucleus pulposus composed of?
fibrocartilage
What is the water concentration in the lumbar nucleus pulposus at birth and after thirty?
birth…88%; thirty…70%
What is the consequence of non-aggregated glycosaminoglycans in the lumbar nucleus pulposus?
the nucleus pulposus will lose water under deformation conditions
What cell is associated with the nucleus pulposus until about age eleven?
notochord cells
What cells are associated with the mature nucleus pulposus?
reticulocyte-fibroblast and chondroblast
Which type of collagen is dominant in the nucleus pulposus?
collagen type II
What general tissue location is described as having an abundance of collagen type II fibers?
cartilage
What is the role of collagen type II fibers based on locations where it is dominant?
it appears to be related to tissues having a deformation-reformation ability
What is the appearance of the cervical annulus fibrosus?
a horse-shoe with the anterior margin thick and the lateral margins tapering to the uncinate process; the posterior margin is tin
What compensates for the thinness of the posterior part of the cervical annulus fibrosus?
posterior longitudinal ligament
What is the organization of the lumbar annulus fibrosus?
it has the 12-14 concentric cylindrical lamellae
What is the water concentration in the lumbar annulus fibrosus at birth and after thirty?
birth…78%; thirty…70%
What is the organizational pattern for glycosaminoglycans in the lumbar annulus fibrosus?
they typically have a binding site for hyaluronic acid and are thus aggregated
Which type of collagen is dominant in the annulus fibrosus?
collagen type I
What is the organizational pattern for collagen fibers in the annulus fibrosus?
they are parallel with one another in a single lamellus and angled
What is the organization of collagen fibers between lamellae?
collagen fibers will be angled in the opposite direction such that a spiral - counterspiral organization is observed
What is the average angle of collagen fibers within the annulus fibrosus?
they average 50 to 60 degrees
What is the origin for the cells of the annulus fibrosus?
sclerotomites
What part of the vertebral body will the cartilage end plate cover?
the cancellous bone at the top or bottom of the vertebral body
What is the principal type of collagen fiber within the cartilage end plate?
the type II collagen fiber
What is the direction of collagen fibers within the cartilage end plate?
collagen fibers are aligned anterior to posterior
What is the earliest indicator of intervertebral disc pathology or degeneration?
changes in the histology of the cartilage end plate
What is the area of maximum metabolic activity in the intervertebral disc?
the transition zone
What part of the intervertebral disc is innervated?
the outer lamellae of the annulus fibrosus
What part of the cervical intervertebral disc is highly innervated?
the middle third of the annulus fibrosus
What are the types of receptor endings in the intervertebral disc?
nociceptors and proprioceptors
What is the relationship between size of the intervertebral disc and receptor endings?
The larger the disc, the greater the variety of receptor endings
The recurrent meningeal/sinu-vertebral/sinus vertebral nerve has typically been shown to originate from what source?
the gray ramus communicans
What part of the intervertebral disc is innervated by the recurrent meningeal/sinu-vertebral/sinus vertebral nerve?
the outer lamella of the annulus fibrosus at the posterior part of the intervertebral disc
What forms the anterior neural plexus of the vertebral column?
fibers from the ventral primary ramus
What forms the lateral neural plexus of the vertebral column?
fibers from the ventral primary ramus, fibers from the white ramus communicans, fibers from the paradiscal ramus communicans, fibers from the grey ramus communicans
What is the name given to the white ramus communicans which becomes embedded within the annulus fibrosus of the intervertebral disc?
the paradiscal ramus communicans
What part of the intervertebral disc is innervated by fibers from the paradiscal ramus communicans?
the outer lamellae of the annulus fibrosus at the lateral part of the intervertebral disc
What is formed withing the perichordal blastema between the sclerotomites?
the intrasclerotomal fissure of fissure of von Ebner
What does the intrasclerotomal fissure of fissure of von Ebner become?
the perichordal disc
What will the dense sclerotomite become?
the upper part of the vertebral segment forming below
