Freyette's Mechanisms Flashcards
Neutral Position of the spine
not a single point, a range in which weight of trunk is borne on the vertebral bodies and discs
facets are not engaged
Fryette’s principles
1) in neutral range, sidebending and rotation are coupled in opposite directions
2) In sufficient flexion or extension, sidebending and rotation are couple in same direction
3) Moving a vertebral segment in any plane of motion will affect movement in all other planes of motion
***1st and 2nd only apply to Thoracic and lumbar
Freyette’s 1st principle (Type I SD)
in neutral sidebending occurs first, then rotation, in opposite directions (think of an N for neutral)
–> like a car, you have to shift (sidebend) before you can rotate wheel
occur in groups, can compensate for type II at top or bottom of the group curve
can also occur alone
maintained by long paraspinals(chronic)
2nd principle (Type II SD)
NON NEUTRAL (Flexed or Extended) - rotation first, the sidebending : in the same direction
maintained by short paraspinals (acute)
tend to occur alone, two are possible
Type II Flexion SD
One facet stuck open when the spine tries to be extended –> acts as a piviot–> segment will rotate and sidebend toward the facet that closes
segment returns to symmetry in flexion
Type II extension SD
on facet is unable to open (stuck closed)–>acts as a piviot–>Rot and SB occur toward the facet that remains closed
returns to symmetry upon extension
Naming Type I SD
Side bending first (because it happens first)
NAMED FOR EASE OF MOTION
Ex: T7SrRL
Naming Type II SD
rotation is listed first
NAMED FOR EASE OF MOTION
Ex: if T7 is prefers flexion and is freer w/ R rotation and R sidebending
T7FrSr
Motion is restricted in…….
the opposite direction of the rotation
if TV5 is restricted in right rotation, then it is rotated left and the SD is Rl
TV1-3
SPs are at level of TPs
TV4-6
SPs are half step below TP
TV7-9
SPs are full step below TP
TV 10
full step below TP
T11
Half step below TP
T12
SP at level of TP
