So non-physiologic strain patterns include vertical
and lateral strains and also SBS compressions.
So vertical and lateral strains are non
physiologic as they move in a shearing fashion.
The vertical and lateral strains have the sphenoid
and occiput moving in the same direction.
And so when they move in the same direction, it's not
no longer that sort of gear-like fashion that occurs
It kinda is due to a trauma and it causes the
bones to kinda move against normal motion.
And so we have two parallel vertical
axis where the sphenoid and occiput
move in the same direction for lateral strains.
And lateral strain is named for how
the sphenoid moves
and what we're really
looking at is to be clear,
we name it for how the greater wing
of the sphenoid moves.
And so here we have a image,
the two blue pipe cleaners are the two
vertical axis with the sphenoid and occiput.
And again, if you try to rotate
2 bones in the same direction,
you'll see how it creates
a shearing effect there.
And so for a lateral strain with
the greater wing to the left,
you see that the sphenoid is displaced a little bit
more to the left while the occiput to the right.
And a lateral strain with the
greater wing to the right,
the sphenoid is going to shift
a little bit more to the right
and the greater wing is now more to the
right side and the occiput is to the left.
So what're you gonna feel in a
lateral strain with a vault hold
So if you start with neutral, if you imagine
the sphenoid shifting to the right,
your fingers on the greater wing, your
pointer fingers on the greater wing
are gonna just kinda shift to the right.
And what's gonna happen with the occiput
or the fingers on the occiput
is they're gonna shift to the left.
So what you kinda get is this parallelogram.
With parallelogram motion your
fingers are kinda shifting
with your pointer fingers kinda shifting to
the right, your pinkie fingers to the left.
So this would be a lateral strain
with the greater wing to the right.
If we take our hand and now just
kinda shift it to the left side,
our pointer fingers are now on the
greater wing shifting to the left
and our fingers on the occiput
are now shifting to the right.
So this would be a lateral strain
with the greater wing to the left
Vertical strain patterns are
non-physiologic cranial patterns.
What happens on vertical strain patterns
is that we're having motion in the same
direction about two transverse axes.
So these are the same axes as
normal flexion and extension,
however, you're having motion
in the same direction.
This causes a shearing effect at the
SBS and what you do is you name
the vertical strain pattern for how the
sphenoid is moving on the occiput.
So in a relative position
of the basisphenoid,
the base of the sphenoid as it is in relation
to the occiput where it meets at the SBS.
So in a superior shear, what you have is the
occiput is kind of rotating into extension and
the sphenoid is rotating
into relative flexion.
So what happens if my left hand is the
sphenoid and my right hand is the occiput.
Our sphenoid bone is going to rotate anteriorly and
our occiput is also going to rotate anteriorly.
And that causes a shearing effect at the SBS
and what you have here is a superior shear
because the base of the sphenoid is gonna
be higher than the base of the occiput.
The opposite occurs in inferior shear.
So our sphenoid is gonna
rotate into extension,
kinda rotating posteriorly and our occiput
is also gonna rotate posteriorly.
And so in inferior shear, the base of the sphenoid
is going to be inferior to the base of the occiput.
So what is this gonna feel like if you'll
have your contact with the vault hold
is that you're going to have your hands
almost like it's connected to an axle.
and then in a superior shear, because
everything is rotating inferiorly,
the fingers are gonna kind of
feel like it's all pointing down,
'cause the sphenoid's gonna
kinda rotate anteriorly,
the occiput's also gonna rotate anteriorly
so all your fingers are gonna kinda
almost like point down towards the floor.
So it's counter intuitive, all your
fingers are pointing inferiorly
but this is the actual motion of a
superior shear, cause remember again,
we're naming for what's going
on at the base of the sphenoid
not what's going on with the
position of the sphenoid itself.
So in a superior shear, our fingers are
all pointing down towards the feet.
And in a inferior shear, all the fingers
are pointing up towards the head.
So again, remember our fingers are on the sphenoid,
the sphenoid's gonna kinda rotate posteriorly
and the occiput is also gonna
kinda rotate posteriorly,
so that takes our fingers and kinda brings
everything up towards the ceiling
with the patient lying supine
and the sphenoid being on top
and the occiput being more
by our pinkies by the table.
So let's apply some of the things
that we learned to this question
So we have a 15 year old football player,
comes in with a history of headache
after being hit underneath the chin
during a football game 5 days ago.
You apply a vault hold and you
detect the freedom of motion
with your fingers rotating in a superior
motion towards the apex of the head.
What is the somatic dysfunction diagnosis?
and describe the motion of the sphenoid
and occiput in its axis.
So here, we have inferior shear
All our fingers are kinda pointing up
towards the apex of the head.
And so, what's happening here is that
we have the sphenoid and occiput
rotating in the same direction
about two transverse axes.
The sphenoid is going to rotate posteriorly and
the occiput is also gonna rotate posteriorly.
And so that causes all your fingers are gonna feel
like it kinda moves superiorly up towards the ceiling.
This is very common with specific
blows, blows underneath the chin, falls
and the opposite may occur if you fell
backwards and kinda hit the back of your head
or sometimes if you sit really hard down on your
tail bone, that could cause a pull of the occiput,
driving and creating a
inferior or superior shear.
So this shearing patterns are
usually secondary due to trauma.
So here we have a question
involving a 2-week old baby,
comes to the office brought in by her mom
complaining of a misshaped head or plagiocephaly
So you apply a frontal occipital
hold and you detect the freedom
of your hand on the occiput
favoring translation to the left
and your hand on the frontal bones
favoring translation to the right.
So what is your somatic
and also describe the movement of the
sphenoid and occiput on its axis
So here this is a little
bit more challenging.
We've been describing the
motion and the movement of the
cranial strain patterns
with a vault contact.
Here, we're looking at a contact of frontal-occipital
hold and we're describing the occiput
translating to the left and your
frontal bone translating to the right.
So what you would feel if you translate
that to a vault hold is your fingers kinda,
our pointer finger shifting to the right and
your pinkie finger shifting to the left.
So this is a lateral strain
with the greater wing to the right.
And so if we have a lateral strain
with the greater wing to the right,
our sphenoid and occiput are rotating in the
same direction about two transverse axes.
So it's important to not only understand what you're
gonna get a sense of in terms of the cranial bones
when you have a vault contact, but
also be able to translate that to
what's going on with the cranium if you
had a fronto-occipital hold also.
So SBS compression is the last
non-physiologic strain pattern
Compression at the sphenobasilar synchondrosis
pretty much will result in a lack of motion.
And so what you get a sense of is when
you place your hands on a vault hold,
is that there's really not a lot
of expansion, flexion-extension,
doesn't really, not a
really good palpable CRI.
A lot of times this is due
to a very severe trauma,
head going through a wind shield at fast
speeds usually a lot of force really directed
towards the midline causing that
compression of the spheoid and the occiput
resulting in a change in the tissue,
resulting in a decrease in motion.
What my teachers have told me is that it almost
feels like when you're palpating the head,
it feels like you're palpating a bowling ball.
It's just very dense, very heavy and really
not a lot of appreciable motion in the area.
So this concludes our review of
the cranial strain patterns
and hopefully you'll be able
to better apply your understanding
of the anatomy and physiology of the cranial
bones to what's going on with the cranium
and be able to diagnose these
strain patterns on your patients.