So different strain patterns exist at the SBS.
So what we're looking at here are physiologic
and non physiologic strain patterns.
So physiologic strain patterns are strain patterns
that usually exist and is not due to trauma.
So, flexion and extension is
normal motion at the SBS.
Your sphenoid and your occiput
will undergo flexion and extension
because they move in about two
transverse axis in a gear like fashion.
And when you move in opposite
directions in the gear like fashion,
that tends to be more physiologic.
Torsions also are considered physiologic and side
bending rotation are physiologic strain patterns.
Your non-physiologic strain patterns
tend to be more due to trauma.
These strain patterns no longer move
in a gear-like fashion.
Vertical shears cause a shearing.
All these vertical and lateral shears both
create a shearing pattern along the SBS
where the occiput and sphenoid are
moving in the same direction and thus
no longer in a gear-like fashion
and SBS compression as it sounds
is really the sphenoid and occiput
really being pushed together
and having a loss of normal
motion in the region.
So cranial flexion and extension
occurs about two transverse axes.
The sphenoid and occiput rotate in
So in cranial flexion or
also called inhalation,
the sphenoid's gonna rotate anteriorly and
the occiput's gonna rotate posteriorly.
This is going to cause the head to
have a increased transverse diameter
and decreased AP and vertical diameter.
What happens is, with the midline
bones when you have flexion,
the paired bones like the temporal
bones will externally rotate.
In cranial extension or exhalation phase,
the sphenoid's gonna rotate posteriorly
and the occiput is also
gonna rotate anteriorly.
This is gonna cause the head to kinda
decrease it's transverse size diameter and
kinda increase it's anterior-posterior
and vertical diameter.
Here also the paired bones are
going to internally rotate.
A good way to picture flexion
and extension head is to use
our Sesame street characters
that we might be familiar with.
And so here we have Ernie,
Ernie displays more of a flexion head.
His head is a little bit more oval, shaped
with a little bit more wider and shorter head.
And so, again in inhalation phase or flexion
phase, the sphenoid and occiput are in flexion.
The paired bones will externally rotate.
And so, this is gonna cause more
of a broaden transverse diameter,
a little bit more narrow
anterior-posterior and vertical diameter,
similar to what you see with Ernie here.
Bert displays more of an extension head.
So Bert's head is a little bit more
oval but more in a vertical direction,
a little bit more taller,
a little bit more narrow.
So the exhalation phase
is more of a Bert head.
So you have extension of the sphenoid and occiput
and then internal rotation of the paired bones
causing that narrow, increase in AP or
anterior-posterior and vertical diameter.
So again, flexion and extension occur
at the sphenoid and occiput.
If you have an exaggeration of flexion
or exaggeration of extension,
then that is the name of that cranial dysfunction.
Here is an image of what's occuring
at the sphenoid and occiput.
So again, the middle is neutral
wherein our starting point
and then flexion you could see about
two transverse axes,
sphenoid and occiput rotate
in opposite directions
and then in extension the sphenoid and
occiput rotate in opposite directions
with the sphenoid kind of rotating posteriorly
and the occiput rotating anteriorly.
So we utilize the vault hold in order to
diagnose what's going on with the cranial base.
Remember that the orientation
changes here a little bit.
You're gonna have the sphenoid more superior to the
occiput with the patient lying supine on the table.
And so, with our vault hold, our pointer finger's
really gonna contact the sphenoid by the greater wing
and our pinkie finger is gonna contact the occiput with
our 3rd and 4th fingers over the parietals and temporals.
And so if we understand the potential change in
shape of the cranium, we could kind of anticipate
what we're gonna get a sense of when we're
palpating the head in the vault hold.
And so, this image is of cranial neutral,
we have our hands on the vault hold,
comfortably resting and sensing
what's going on with the head.
Now with cranial flexion, remember that
the transverse diameter is gonna increase.
So if my fingers are on the sphenoid and the
occiput and I have increase in AP diameter,
my fingers are gonna spread out a little bit.
And then because the vertical diameter is
gonna decrease, I'm gonna feel my fingers
kinda shift a little bit more inferiorly
towards the feet of the patient.
So what you're gonna feel in cranial
flexion from a vault hold perspective
is your fingers' gonna spread out a little bit maybe
expand a little bit to get a little bit wider
and move a little bit more
down towards the feet.
The opposite's gonna occur in cranial extension.
So remember in cranial extension, our transverse
diameter is gonna decrease so our fingers
are gonna kinda come closer together and then
our vertical diameter is gonna increase.
So our fingers are gonna kinda move superiorly
up towards the top of the head a little bit.
So remember what would you kind of
feel if you had flexion and extension
is you're gonna get a sense
of a Bert and Ernie head.
So you're gonna feel your flexion
phase and then your extension phase.
This is greatly exaggerating what's going on
at the cranium
but for you to visualize what you
might feel in the vault hold,
our fingers are gonna spread out
and move out laterally for flexion
and then our fingers are gonna come
close together, move superiorly up
towards the apex of the head in extension.
Another strain pattern that you could feel
is the sidebending rotation strain pattern.
Again this is a physiologic strain pattern, our motion
here is occuring about two vertical axes and one AP axis.
So first, the sphenoid and occiput are going to
rotate on opposite directions on two vertical axes.
That's gonna cause a side bending
of the sphenoid on the occiput.
So one side is gonna be more concave and
one side is gonna be more convex or wide.
The side of the convexity
is going to be the side
that the sphenoid and occiput is gonna
rotate about a AP axis.
So what we're going to get is a
side bending on two vertical axes
and then a rotation about the AP axis.
So the sphenoid and occiput are still
rotating in opposite directions
on the vertical axis but in the same
direction in the AP axis.
We're gonna name the side bending rotation on the
side of that convexity or the side of that wide side,
the side that the rotation is
occuring towards on that AP axis.
When you have a side bending
you're going to actually see some
asymmetries that may occur in the face.
And so, here are some different landmarks
on the face that you could get a sense of
where you might see asymmetry based on the
side of convexity and the side of concavity.
So here is an image demonstrating
the motion and movement.
We have two vertical axes and so you have the side
bending that occurs at the cranial base at the SBS.
In the middle you have neutral and on the right here
you have the rotation occuring about the AP axis.
So, this is a right side bending rotation
where more convex on the right side
and then we rotate both the
sphenoid and occiput to the right.
So here is a image of what you're
gonna feel with your hands.
So remember, if we are side bending and we
have a side that is a little bit more convex,
what we're gonna get a sense of is our fingers are
gonna spread apart a little bit more on that side.
So let's take right side
bending rotation for example.
So if I have a right side bending rotation and I have
my sphenoid and occiput rotate on two vertical axes,
that's gonna create a gapping
where my sphenoid and occiput
is going to spread a little
bit more on the right side.
So my fingers are gonna
spread out on the right side,
whereas my fingers on the left hand are
gonna come a little bit closer together.
So that's gonna account
for the side bending.
Now we're gonna have a
rotation on the AP axis.
So remember again the
orientation in a vault hold
is that the sphenoid is on top,
the occiput's on the bottom.
So if I have a rotation to the right,
that's gonna bring my entire hand down towards
the feet of the patient on the right side.
Whereas on the left side, my hands
are gonna come closer together
and then up towards the vertex of the head.
So in a right sidebening rotation,
our fingers are gonna spread on the right
side and go down towards the feet.
Where on the left side, my fingers are gonna
come close together and up towards the head.
The opposite's gonna occur in a
left sidebending rotation.
So in the left side bending rotation
on the vault hold,
our fingers on the left side are gonna
spread out and rotate towards the feet
and our fingers on the right side are gonna come
closer together and come up towards the head.
Based on what's going on with the SBS and
how the vault is accommodating for that.
Cranial strain patterns include torsions.
So torsions are a physiologic strain pattern.
The sphenoid and occiput are rotating
in opposite directions about a AP axis.
So there is one axis, one single AP axis,
kinda from the nasion from to opisthion
And what happens is you're going to have
the torsion of the sphenoid and occiput
and what you do is you name the torsion for
the side of the greater wing of the sphenoid.
So what you're gonna see is one side of the
sphenoid is gonna be higher than the other.
And so, if you are rotating
the sphenoid clockwise,
what you're going to get is a left higher wing
and so that will be a left torsion.
If you rotate the sphenoid counter-clockwise,
that's going to be a right greater wing that's higher
and that's going to be a right torsion.
Here's a image of that a little bit more.
You could see the pipe cleaner
there, it's the AP axis.
And so you have rotation of the sphenoid
clockwise creating a left torsion
and the rotation of the sphenoid
counterclockwise creating a right torsion.
So looking at what we're
gonna get a sense of,
if we have a torsion and we're using
the vault hold to palpate the cranium.
So again, if we're palpating the cranium and we're
getting a sense of a torsion, what you're gonna feel
is that the greater wing of the
sphenoid is going to rotate
and the hands are gonna rotate
in opposite directions.
And so, our right hand is gonna kinda
rotate superiorly in a right torsion
and the left hand is gonna
kind of rotate inferiorly
and the opposite's gonna
occur in the left torsion.
Our left hand is gonna rotate superiorly whereas
the right hand is gonna kinda rotate inferiorly.
The contact on the greater wing is gonna
feel like it moves more superiorly
and the rest of the fingers
are also gonna follow.
So let's do some practice question applying
the knowledge that we just reviewed.
We have a 20 year old female with a history of migraine,
comes in with a headache for the past 4 hours.
When you're applying a vault hold, you note
increased fullness on the right side of her head.
You note that your fingers on the right
hand favor inferior motion towards the feet
and the fingers on your left hand favors
superior motion towards the apex of her head.
What is the cranial
somatic dysfunction here?
and describe the motion of the
sphenoid and occiput on it's axis.
So, it's important based on your findings of
the vault hold to be able to make a diagnosis.
But also, once you make the
diagnosis to be able to explain
what is actually happening biomechanically
at the sphenoid and the occiput.
So here, the vault hold is describing
a right side bending rotation.
You have that extra fullness on the right side,
your fingers are spreading out
and kinda moving more inferior
towards the feet on the right
and the fingers on the left are coming more together
and coming up towards the apex of the head.
So we have a right sidebending rotation which
is a rotation of the sphenoid and occiput
in opposite direction on two vertical
axes and then a rotation on the AP axis.
In this case, because it's a right side bending
rotation, it's gonna rotate inferiorly to the right.