Suggested Review
It will be helpful to review the section on Normal Neutral Mechanics and the section on Normal NonNeutral Mechanics. You should pay particular attention to how L5 responds to sacral torsion. Remember that in both sections, motion of L5 is characterized in the absense of dysfunction, meaning that both facets of L5 are free to fully open and close.

Overview
In this section, you are presented with examples in which the sacrum is always dysfunctional (sacral torsion has been diagnosed) and L5 is may be functional (adaptive) or L5 may be dysfunctional (nonadaptive).

Left on Right Posterior Sacral Torsion -- L5 Adaptive

A posterior or backward torsion of the sacrum to the left on the right oblique axis (LOR) results from an inability of the left sacral base to move into anterior nutation (sacral flexion) with extension of the lumbar spine. In the neutral position, the sacrum is side bent right and rotated left. When lumbar extension is introduced, asymmetry increases. When lumbar flexion is introduced, symmetry improves.

  • In the neutral position, when the sacrum is side bent right and rotated left, L5 is considered to be adaptive when it rotates to the right and sidebends to the left (Click here to see an image of left on right sacral torsion with the patient in the neutral position).
  • In the backward bent position, when the sacrum is more side bent right and rotated left, L5 is considered to be adaptive when it rotates to the left and sidebends to the left (Click here to see an image of left on right sacral torsion with the patient in the backward bent position).
  • Click here to visualize left on right sacral torsion with the patient moving from neutral to the backward bent position.

Left on Right Posterior Sacral Torsion -- L5 NonAdaptive (FRSright)

Non-neutral dysfunctions at L5 (FRSright) often accompany a left on right sacral torsion. An FRSright at L5 can be identified when the patient is backward bent and L5 appears rotated right when compared to a left rotated and right sidebent sacrum.

  • In the neutral position, when the sacrum is side bent right and rotated left, L5 is considered to be nonadaptive when it fails to rotate fully in the opposite direction of the rotated sacrum (i.e., to the right) (Click here to see an image of left on right sacral torsion with the patient in the neutral position).

  • In the backward bent position, when the sacrum is more side bent right and rotated left, L5 is considered to be nonadaptive when it fails to follow the sacral base position (i.e., rotate to the left) (Click here to see an image of left on right sacral torsion with the patient in the backward bent position).

  • Click here to visualize left on right sacral torsion with L5 adaptive and nonadaptive shown side-by-side. Remember that with an FRSright dysfunction, the left facet of L5 can not close, thus preventing left sidebending from occuring.

Right on Left Posterior Sacral Torsion -- L5 Adaptive

A posterior or backward torsion of the sacrum to the right on the left oblique axis (ROL) results from an inability of the right sacral base to move into anterior nutation (sacral flexion) with extension of the lumbar spine. In the neutral position, the sacrum is side bent left and rotated right. When lumbar extension is introduced, asymmetry increases. When lumbar flexion is introduced, symmetry improves.
  • In the neutral position, when the sacrum is side bent left and rotated right on the left oblique axis, L5 is considered to be adaptive (normal) when it rotates to the left and sidebends to the right relative to the sacrum (Click here to see an image of right on left sacral torsion with the patient in the neutral position).

  • In the backward bent position, when the sacrum is more side bent left and rotated right, L5 is considered to be adaptive (normal) when it rotates to the right and sidebends to the right (Click here to see an image of right on left sacral torsion with the patient in the backward bent position).
  • Click here to visualize right on left sacral torsion with the patient moving from neutral to the backward bent position.

Right on Left Posterior Sacral Torsion -- L5 NonAdaptive (FRSleft)

Non-neutral dysfunctions at L5 (FRSleft) often accompany a right on left sacral torsion. An FRSleft at L5 can be identified when the patient is backward bent and L5 appears rotated left when compared to a right rotated and left sidebent sacrum.

  • In the neutral position, when the sacrum is side bent left and rotated right, L5 is considered to be nonadaptive (dysfunctional) when it fails to rotate fully in the opposite direction of the rotated sacrum (i.e., to the left) (Click here to see an image of right on left sacral torsion with the patient in the neutral position).

  • In the backward bent position, when the sacrum is more side bent left and rotated right, L5 is considered to be nonadaptive (dysfunctional) when it fails to follow the sacral base position (i.e., rotate to the right) (Click here to see an image of right on left sacral torsion with the patient in the backward bent position).

  • Click here to visualize right on left sacral torsion with L5 adaptive and nonadaptive shown side-by-side. Remember that with an FRSleft dysfunction, the right facet of L5 can not close, thus preventing right sidebending from occuring.

Left on Left Anterior Sacral Torsion -- L5 Adaptive

A anterior or forward torsion of the sacrum to the left on the left oblique axis (LOL) results from an inability of the right sacral base to move into posterior nutation (sacral extension) with flexion of the lumbar spine. In the neutral position, the sacrum is side bent right and rotated left. When lumbar flexion is introduced, asymmetry increases. When lumbar extension is introduced, symmetry improves.
  • In the neutral position, when the sacrum is side bent right and rotated left, L5 is considered to be adaptive when it rotates in the opposite direction of the rotated sacrum (i.e., rotates to the right) (Click here to see an image of left on left sacral torsion with the patient in the neutral position).
  • In the forward bent position, when the sacrum is more side bent right and rotated left, L5 is considered to be adaptive when it follows the sacral base postion (i.e., rotates to the left) (Click here to see an image of left on left sacral torsion with the patient in the forward bent position).
  • Click here to visualize right on left sacral torsion with the patient moving from neutral to the backward bent position.

Left on Left Anterior Sacral Torsion -- L5 NonAdaptive (ERSright)

Non-neutral dysfunctions at L5 (ERSright) often accompany a left on left sacral torsion. An ERSright at L5 can be identified when the patient is forward bent and L5 appears rotated right when compared to a left rotated and right sidebent sacrum.
  • In the neutral position, when the sacrum is side bent right and rotated left, L5 is considered to be nonadaptive when it fails to rotate fully in the opposite direction of the rotated sacrum (i.e., to the right) (Click here to see an image of left on left sacral torsion with the patient in the neutral position).
  • In the forward bent position, when the sacrum is more side bent right and rotated left, L5 is considered to be nonadaptive when it fails to follow the sacral base position (i.e., rotates to the left) (Click here to see an image of left on left sacral torsion with the patient in the forward bent position).
  • Click here to visualize left on left sacral torsion with L5 adaptive and nonadaptive shown side-by-side. Remember that with an ERSright dysfunction, the right facet of L5 can not open, thus preventing left sidebending from occuring.