Axial Skeleton Flashcards
When does the cervical spine curve develop
2-3 months
When does the lumbar spine curve develop
6 months
Purpose of the curves
Weight distribution
Handle compressive forces
Disc is thicker anterior in
Cervical and lumbar spines
Disc is thicker posteriorly in
T spine
Sharpeys fibers attach anulus to
Vertebral body
Annulus keeps nucleus
Under pressure (hydraulic)
Annulus innervated by the
Sinuvertebral nerve
Proteoglycans are
Hydrophilic
Nucleus is a matrix of
Glycosaminoglycans (chondrotin and keratin sulfate) linked to proteins to form PGs
Endplate portion adjacent to IVD is primarily
Fibrocartilage and strongly bound to nuclear and annular regions
End plate portion adjacent to vertebral body is primarily
Hyaline cartilage, weakly attached to vertebral bodies
End plate contributes to pressure on nucleus and barrier to prevent loss of
PGs and water from disc
Consequences of the changes in IVD as we age
Compression fractures of vertebral body
Less space in inter body joints
Osteophyte formation/bone spurs
Ligamentum flavum attaches to
Lamina
During degeneration of IVD, there is a reduction in
Elastin and PGs
During degeneration of the IVD, there is an increase in
Collagen content (more type 1)
Motion of the spine depends on
Size of disks
Orientation of the facets of the Z joints
Spinal posture
Extensibility of muscles ligaments and capsules (flexibility)
In lateral flexion the superior vertebrae
Laterally tilts, rotates and translates over the inferior vertebra in frontal plane
Axial pressure on the spine: pressure falls on the
Nucleus, then annulus, then end plate, then vertebral body
In axial pressure, the _______ is the first to fail
End plates
Stable functional unit
Articulations
Ligaments and joint capsules
Muscles
Bending snd torsion forced on the spine more likely to cause damage than
Compression forces
Torsion stress occurs from twisting or rotating the spine, causing ____ and _____ stresses on the annulus
Tensile and shear
Water diffuses out of the IVD during
Loading
Water diffuses into IVD during
Unloading
Asymmetrical compression force will cause
Radial bulging of the disc
In compression, forces transmitted to
End plates and vertebral bodies
Compression increases internal pressure of the disc and stretches the
Annulus fibers
Creep results in
Loss of disc height
Increased Bulging of disc
Constant load on the disc may eventually lead to
Buckling or prolapse of anulus
In creep, the load shifts gradually from the nucleus to place more load anulus, especially
Posteriorly
