Spinal Mechanics

for Structural Bodyworkers

R.Schleip, 4th edition, July 2002

Basic Biomechanics

In sidebending of three and more vertebrae their anterior aspects will tend to rotate towards the side of the convexity. And vice versa: if several vertebrae rotate to one side, they will tend to sidebend with their convex side towards the direction of their rotation.

(This is for two reasons: first because the disks in front will tend to slide partially out of their compression by turning with their ventral sides towards the convexity. Second the stretched ligaments between the TPs (transverse processes) on the convex side will tend limit this motion, and so rotate the vertebrae backwards.)

 Please note that anatomical directions are always relating to the front/top aspect of the described element. I.e. if a vertebra is sidebent to the right, its left TP goes higher, and in a rightward rotation of a vertebra its SP (spinous process) goes to the left.

Osteopathic Assumptions(after H.Freyette and P.Greenman) 

  • Lumbar & thoracic vertebra rotate usually (i.e. in "neutral position") to the opposite side of their sidebending. This is in tune with the above biomechanical principle and is called Type 1 motion in osteopathy. (Note: apparently rotation is described in this rule in relation to the frontal plane of the whole body, whereas sidebending of a vertebra is described in relation to the vertebra below).
  • Sometimes - when this part of the spine is either in hyperflexion or in hyperextension - a lumbar or thoracic vertebra rotates to the same side of its sidebending. This is called a Type 2 fixation.
  • Type 2 fixations are further classified as "flexion fixations" (that flex but don't extend well) or "extension fixations" (which are stuck in extension).
  • Flexion fixations are also called "open fixations", and extension fixations "closed fixations".
  • In flexion fixations it is assumed that the facet joint on the side of the anterior TP is fixated; and extension fixated vertebrae would be fixed on the side of the posterior TP.

           This is tested by comparing forward bending (FB) and backward bending (BB). If a bigger lump (= posterior TP) disappears in FB, then it is a flexion fixation; whereas if the lump disappears in BB, it is an extension fixation.

           The following mnemonic slogan from some osteopaths might be helpful:

 Forward bent and lump is nixed: Far facet is open fixed.

Backward bent and bump away: Bump facet is closed today..

Which means: If the lump disappears in FB, then the facet joint on the opposite side as the lump is in flexion fixation.

Whereas if the lump disappears in BB, then the facet joint on the same side as the lump is in extension fixation.

  • Normal motion of C2-7 is Type 2.
  • Normal movement of occiput on atlas is Type 1; but first 5 degrees of all occiput movements should be free without any atlas participation.
  • For cervicals the ability to sidebend to right and left are compared (translation test):
    • Flexion fixated cervicals don't sidebend very well to the side of their fixation in BB. The flexion fixed facet is on opposite side to the rotation of the vertebra.
    • Extension fixated cervicals don't sidebend well to the opposite side of their fixation in FB. The extension fixated facet is on same side to which the vertebra is rotated.

The mechanics about Type 1 are currently generally accepted in medical science worldwide. There is also considerable agreement in regards to Type 2 mechanics for C2-7. Yet there is still considerable discussion among researchers and practitioners of different schools as to the above described assumptions about Type 2 fixations for the lumbar and thoracic spine. See my brief article ‚Questioning Freyette’. 


 Illustrations

 spinalmech1

 For clarification this graphic symbol represents the posterior aspect of a vertebra with its two TPs (but no SP shown).


Type 2: Flexion Fixation

 Flexion (open) fixated facet joint

 Spinalmech2

SB to left restricted, specially in BB

(i.e.: more bump in BB, less bump in FB)


Type 2: Extension Fixation

 Spinalmech3

 extension (closed) fixated facet joint

SB to left restricted, specially in FB

(i.e.: more bump in FB, less bump in BB)


Osteopathic Techniques for Type 2 Fixations

 Lumbars & Thoracics

            If flexion (open) fixed, put client in BB over your fulcrum to close the facets.

            Then derotate to the opposite side of the lump.

            If extension (closed) fixed, ask client to push vertebra towards you in FB.

Cervicals

            Flexion fixed cervicals are treated in BB, extension fixed ones in FB.

            Direct technique: Move head & neck to increase the sidebend & rotation of the vertebrae. Wait and then ask client to sidebend and rotate head back to center against your resistance for 3-4 seconds. Release and test if it now sidebends and rotates better to the restricted side. Then do same thing to other side.

            Indirect technique: Move head & neck to take vertebra into the direction it is rotated and sidebent. Wait for vertebra to go into its pattern first and then to unwind. Follow the vertebra's unwinding back, but don't push it further.

  

Additional Rolfing Guidelines (from J.Maitland, M.Salveson, J.Sultan)

            General strategy:

            - First make sure body is prepared (spec. both ends of spine and acetabulum) to

            sustain deeper spinal work.

            - Then address any restrictions in cranium, atlanto-occipital junction, pelvis,

            sacrum and lumbo-sacral junction.

            - Then diagnose all Type 1 & 2 fixations.

            - Then treat all Type 2 fixations.

            - Then all Type 1's.

            - Finally treat all rib dysfunctions.

If a vertebra is restricted in flexion & extension, treat the most restricted facet first.

            If you are only doing cervicals, treat C2-7 first before treating atlas & axis.

With Type 1 fixated lumbars or thoracics: work erectors on convex side in the spinal groove in a lateral direction, and work on the erectors on the other side from their lateral borders towards the spine.

Information for this handout is derived from publications by

J.Maitland, M.Salveson, J.Sultan, P.Greenman, J.Basmajian


Easy Review

FLEXION-Fixation

(= open fixation)

EXTENTION-Fixation

(closed fixation)

  • Flexes, but does not extend
  • Facet on anterior TP is fixated
  • Bigger lump (= post. TP) appears in BB 
  • "FB the bump is nixed,

far facet is open fixed"

  • SB restricted to the side of fixation

in BB

  • Vertebra rotated to opposite side of fixation
  • Extends, but does not flex
  • Facet on posterior TP is fixated
  • Bigger lump appears in FB
  • "BB the bump away,

near facet is closed today"

  • SB restricted to opposite side of fixation in FB
  • Vertebra rotated to side of fixation

 Three Step Protocol

For Lumbars & Thoracics

1) Find out

in sitting or SL if one TP is more posterior.

(E.g.if the more posterior TP is on R side, then it is SB to R, and R-rotated)

2) Check

if the lump gets more obvious in FB or BB

3) Treat

If more in FB

(then it is extension fixed on that side):

Treat in FB,

have them push this TP towards you

If more in BB

(= flexion fixed on opposite side):

Treat in BB over fulcrum,

rotated to opposite side of the lump


Check Questions:

Based on the above described osteopathic approach, always answer the following 3 questions for each person:

  1. What is your diagnosisof the vertebra position
  2. Using the same simple graphic symbol for a vertebra used in this article, make a sketch illustration of the described vertebra position and side of fixation
  3. How would you treat this fixation?

Before starting here is an examplewith the correct answers for oriention:

"John shows a lump (posterior TP) on the right side of L2. This becomes more obvious in BB"

  1. Diagnosis: L2 is flexion fixated on the left.
  2. Illustration:

Spinalmech4

 c) Treatment: Put client in BB over fulcrum. Then derotate vertebra to the left.


Ready to start? Here we go:

  1. Jenny has a lump on the right side of T10, which seems to disappear in BB.
  1. Diagnosis:
  2. Illustration:
  3. Treatment:
  1. Peter has a lump on the left side of L4, which becomes more obvious in FB.
  1. Diagnosis:
  2. Illustration:
  3. Treatment:
  1. Susan has a lump on right side of T4, which becomes less prominent in BB.
  1. Diagnosis:
  2. Illustration:
  3. Treatment:

4) Bill has a lump left of T7. It becomes more prominent in BB.

  1. Diagnosis:
  2. Illustration:
  3. Treatment:

5) Sarah's C5 shifts easily to the left, but less free to the right. This becomes more obvious in FB.

  1. Diagnosis:
  2. Illustration:
  3. Treatment:
  1. Tom's C2 does not translate well to the left, specially in BB.
  2. Bob's C7 does not translate well to the left, specially in FB.
  3. A lump on the right side of L4, becomes more prominent in BB
  4. A lump on the left side of T4, disappears in BB.
  5. C3 does not translate well to the left. Less obvious in FB.
  6. Lump on left side of T1 disappears in BB.
  7. C5 translates better to right than to left. More obvious in BB.
  8. Lump on left side of L3, more obvious in BB.
  9. Lump on right side of T10, less prominent in FB.
  10. Lump left of T,1, specially in FB.
  11. C4 does not translate well to left. Less obvious in BB.
  12. C12 translates well towards lump on nose. Less obvious when blind J

Note: If you are not that familiar with this, it will take you several minutes for each person. Yet as you keep practicing you will become quicker and more fluent. In order to apply this without much hesitation in a daily practice, you will need to be able to answer the 3 questions all together in less than half a minute per described person.