Pelvic torsion, anatomically correct

1
Pelvic torsion, anatomically correct
2
The Symphysis Pubis Anatomically Correct Pivot
Point
A pivot point at the symphysis pubis minimizes
stress at this joint. The iliac crest is lowered
as well, as expected. However, the traditional
explanation of the PI-related physiological short
leg is imperiled.
pivot point at symphysis
3
Sacral Gyroscopic Accomodation

• The sacrum copes with inter-innominate torsion by
  a complex series of rotations and/or linear
  translations. The rotations are
• nutation/counternutation about the X axis
• lateral flexions about the Z axis
• rotation about an oblique axis perpendicular to
  its base, some 350 off the Y axis
• This description is merely approximate.

4
Nutation, Kapandji
5
Nutation, Diane Lee
6
Nutation is a sacroiliac movement, not purely
sacral movement
As the ilium rotates posteriorly, the sacrum is
left relatively anterior. This is equivalent to
nutation, even though the sacrum as visualized in
this illustration is the fixed point.
7
Sacral rotation around the quasi-y axis and
lateral flexion around the z axis
8
Positional Changes in Pelvic Distortion (after
Cramer)
Sacral rotation is depicted around all 3 major
axes.
9
The paradox of the anterior and posterior sacral
base

• The left innominate subluxates posteriorly.
• The left sacral base travels with it, but
  incompletely.
• The sacrum is left anterior to the ipsilateral
  innominate, but simultaneously posterior to the
  contralateral sacral base.

left sacral base posterior to right sacral base
sacral base anterior to innominate
10
Posterior sacrum on ilium
Posterior sacrum on ilium wedges ilia apart.
Probably not the common SI subluxation.
11
The inferior sacrum Posterior or anterior to
ilium?
It is a Gonstead premise that the sacrum will
always rotate posteriorly on the inferiorly
tipped side. I have not been able to locate the
biomechanical explanation underlying this premise
within the Gonstead literature. No consideration
is given to the possibilities of an
anteriorinferior, posterior superior, or purely
inferior sacrum. It should be pointed out here
that much consideration has been given to the
anteriorinferior sacrum in the chiropractic
literature outside the Gonstead system. Logan
Basic Technic is based on the foundation of an
anterior-inferior sacrum. Janse, Illi, and other
chiropractic researchers consider sacral
misalignments other than posterior-inferior. This
author, your very own truly humble narrator, can
shed no new light on this issue. He can only
point out the discrepancies that exist within the
literature. Valid scientific research into spinal
and pelvic biomechanics is necessary to clear up
such basic controversies. LACC Technique
Instructor
12
Theories of pelvic distortion can actually get
more complicated!