Introduction to the relation between thoracic mechanisms and lumbar spine pain.

These different mechanisms are far more important and hard to handle and at stake in the lumbar spine issues.


The diaphragm is not working as a car piston; this is the cylinder that opens up. We may target the key points of the spine mechanisms by studying his relation to the vertical position.


The vertical position is an abstract line that needs to be defined precisely from the ground. And it will be very important to consider her as a reference basis that can be modulated along with his interactions with the body balance.


The diaphragm is a membrane that is not an ordinary muscle, but attached to the ribs that interact with it, which is something you realize when you try to control this vertical line we just mentioned.


1 - The vertical line and the spine seen from the side.


From the front the vertical line goes from the ground and follow the axis of the ribs if the column is straight. From the side it is more complicated; normally the vertical line goes

From the side it’s more complicated, normally the vertical line goes from the ground to ahead of the tibiotarsal, then slightly backward the femur/pelvis articulation then at the centre between the sacrum and the 5th vertebra, then at the centre between the 1st and 12th lumbar, then at the centre of the 1st dorsal and the 7th cervical and the then finally by the head. It is very precise and easy to understand but what is less easy is the relationship between all these points that goes thought the vertical line.


Transition areas.


To understand the concept of this vertical line is very easy, just picture the branch of a tree, try to bend it with 4 hands, every time you change the direction of your bend you will put the branch under a new form related to the vertical line, if you break it you will create an articulation. If you don’t have a non-deformable area, the transition area will be replaced by a translation that you will the end articulate. It means that in order to handle the bends of your back you will need to handle the 2 other ones. To understand this keeps the pain to a real level.

How to handle the vertical line of the inferior elements of your body?


The sinusoids. They are composed by the dissociation the mono and poly articulations of the different muscles. These allow the control of the vertical line until the pelvis. The control of the vertical line at the tibiotarsal level and the coxal-femoral level is a key point.


The control of the vertical line can be easily pictured by using a chair. You place yourself (your knees) in front of it without touching it. If the chair is well positioned, you will play with the 2 sinusoids that share the vertical line from the tibiotarsal to the pelvis.


This double sinusoid doesn’t go from part to the other of the knees, if these elements are not correct you will get a “flexum” or a “récurvatum” of the knees.


If you use the chair properly, you may turn your pelvis in one or the other direction, and then the rachis will come along either you are closer or not from the chair. In order to know what’s going on above the coxal-femoral you will have to stop the ankles moving.


The way the sinoides works shows mechanisms linked to the knees articulation. The control of the vertical line will lead to control the rachis first and then the thorax linked to the ribs.

The central bend is linked to the thorax. She’s linked not only to the vertical position but also the thorax that also have a vertical line as well, linked to the previous one through the muscular pillars. The thorax is linked to the dorsal column, but by the diaphragm is also linked to the back column. That’s what I call the anatomic pillars of the diaphragm.

2_ The vertical line of the thorax seen from the side and the pillars. 


This line goes by the phrenic centre and by the centre of cervical bends to the scalene and anatomical pillars. The thorax is positioned between 2 transition areas at the vertebral level C7 D1 and D12 L1 backward to the sternum in a vertical and horizontal way. Therefore he takes a shape linked to the back bend and the position of the sternum.

By starting with the control of the thorax and the dorsal rachis you do not interfere with the cervical and dorsal.


The diaphragm/intercostals couple and the empty pleural.


In charge of the breathing in and out process through the empty pleural’s action, we do not know him less by his relationship with the skeleton vertical line than with his relationship with the pillars. I tried to show this many years ago with the scoliosis.


Before linking together all these elements, we need first to share them with the following images.


You may see, that you not only have a thoracic space but also an abdomen one and a third one that I call; the inside space of the diaphragm. In this space there is the pulleys axis that allow the diaphragm to contract him without moving. Every contraction goes by the phrenic centre’s bisector and the centre of the anatomical pillars. (Different colours by plans)



3_The vertical line of the hemithorax (front and pillars)


Muscles that goes thought the centre of the membrane by connecting the 2 hemithorax compose the diaphragm. But nothing stops them to contract themselves without going through the center. They do it very often in front (not very often with the scoliosis by reaching a level that any compensatory movement can fix).


The pillars are complementary to every crossed digitation. But they are positioned under the diaphragm and linked to the intercostals of the 6 and 7th ribs. You may see it by looking at the following drawing.

5_The pelvis.


You have to compare the pelvis to a vertebra with a strange shape. The pelvis helps to position the diaphragm’s pillars by the mean of a rotation linked to the back bend from the transition area D12 L1. He is part of the column of the back but also he pulled away by the tibia/femur angles, which makes him work as a biele. At the rachis level everything is done so there no articulation possible.


The dorsal bend and the thorax

One-piece stick together. The costal bow is complex element. The best way to understand it is to position him with the vertical line. Before being positioned with the vertical line he has to be rejected backward first, to be articulated with the transverse apophysis.


The bow then stands to the posterior face before being attached to the sternum. Every time the angle is going backward the thorax become flat. If he goes forward he becomes thick. The vertebras gathered from top to bottom lead to form the posterior face of the thorax. The sternum goes sideway from the side linked to the rise of the diameter of the thorax, but this decrease or increase whether the angle is pulled away forward or backward. From the posterior face the bows are bending forward and downward by make a succession of angles that lead to the side faces of the thorax. Once bended a second time to be attached to the sternum the bow is taking the shape of a face cut half, the other face making a costo-abdominal face.


The dorsal/rachis mobility.


Gap of the transition area D12 toward the vertical line. This I call a “phagocytosis” of the lumbar column done by the means of the dorsal column when this area goes downward. Very common when the 12th dorsal goes toward the axis of the 1st then to the 2d then 3rd and 4th smashing progressively all the discs and changing the shape of the body.


The importance of finding the transition areas is the key.


The drawing on the right shows the consequences of the transfer of the area D12 L1 to L4 L5 on the anatomical pillar’s orientation. Here I kept the transition area C7D1 and the orientation of the scalene, but most of the time this transition area will move and the scalene orientation will change as well. There is always a link intercostals/diaphragm, but a non-uniform function that will make a thorax with a peculiar shape.

 The thoracic morphology and the diaphragm/intercostals couple.


The flat thorax.


He is the easiest element to study because he may have 4 different faces.


Breathing in and out of a flat thorax.


Once the thorax is opened, you get breathing out that with the help of the intercostals bring back the costal grill to his primary position. Breathing in and breathing out together in the same inversed function. If it starts from somewhere in the bonchitique centres it will come back to the same point from the edge to the centre.

This is the same if all the digastric muscles work simultaneously in the orientations that match the 3 dimensions of the space. Which is something that cannot be the case for a flat thorax. A flat thorax is opened by the digitations contractions with a front orientation.


This allows the sterno-costal angles to rise by moving the bisectors outside, which stretches the frontal part and reduce her vertical part. If at the breathing out the bisectors stayed at a different place these angles will not be able to come back to their primary value.


The costal angles are complementary to each other, if you move the bisectors in the front space then the sagittal plan will move as well when breathing out toward the phrenic centre, which will reduce the horizontal part and rise vertical part. This is in this peculiar situation that the diaphragm digitations work when breathing in and out.


The position of the bisectors determines the shape of the thorax. If you change the positions of the anterior and posterior sagittal parts and turn the sagittal angles by putting them closer to each other you will get a kind of “sagittal sandwich”, impossible to open but that will close himself up.


But with this kind of morpho-type you can have an asymmetric close up towards one of the pillars, one of the plan used as a fixed plan for the other, then the phrenic centre will move along. Then you will get a different orientation compared to the diaphragm ‘s pillars and it will change the position of the vertical line.


My motto is very simple, I can tell an orthopedist surgeon, here is a thorax without all his interns organs, he has, let’s say 6 digitations for the hemi-thorax (flat thorax), 4 anterior one, 4 posteriors ones, four on the side. So 4 anterior one, 4 posteriors opposed horizontally in the sideway orientation of the intercostals. Two are on the side of the hemi-thorax and 2 on the side of the other one, not really opposed to each other by their rising parts because they are shorter, but essentially in the 3rd dimension. When breathing out you get the sternum going closer to the posterior plan. In case you would like to change his shape what would you do ?


The scoliosis and the different pressure of the different surfaces.


By going through the pillars, the digitations have problem to keep the bisectors steady. We have to consider the fact that each hemitorax has dysfunctions linked to different type of pressure. Each digitation behaves like she is alone from his bisectors. The actions of the digitations is shared on the horizontal part of the diaphragm just like a on a clock screen. With the flat thorax we gave each digitations the same way on the 2 hemithorax: 2 digitations, so 3 spaces on each side. Just like the thorax and the column are linked, the thorax rotation will be balanced by the rachis, and you will be blind. You will be in a scoliosis situation.

Thick thorax.

A thick thorax is even more complicated because you don’t have any of the previous mentioned plans. Not only you don’t have plans, but also if the sternum rises in the sagittal plan he turns himself down.

 Diaphragm :intercostals exhaust.


We have seen that the digastric muscles of the diaphragm take are opposed to their thorax contraction from the bisectors in the opposed contraction of the thorax by going through the anatomical pillars. Under these conditions the muscles open up the thorax in the 3 dimensions. But we have also seen with the flat thorax that he cannot open up himself


But we know that a flat thorax cannot be opened sideway, the digitations anterior posterior with the lag of their bisectors when breathing out are straightened without moving at their angles when breathing in. These digitations are used as a line useful to the front and angle mobility. We know that she in charge of a lag of the bisectors outside. This is what I call a diaphragmatic way out.

This is the bisectors position between rising part and horizontal part that is in charge of a simultaneous contraction in all plans. The diaphragmatic contraction with the intercostals works as a couple. If you change the positions of the bisectors, you will change the orientations of the intercostals contraction. Here we get a diaphragm/intercostals breathing in.


We have seen that when breathing out if the bisectors of the front digitations do not come back to their normal position, they will be used as a reference point when intercostals will contract. They are going down from the side by moving the bisectors position. Here we get a diaphragm/intercostals breathing out.

Diaphragm/intercostals/abdominal exhaust.


The thorax is linked to the shape of the rachis, the diaphragm and the intercostals are linked together to the shape of the thorax, and the pelvis is a kind of weird vertebra therefore linked to the thorax. The muscle couple pelvis/thorax is an intercostals musculature of a wide dimension. She is working the same way. She follows the malfunction of the intercostals/diaphragm couple. It means this a dissociation of the obliques. Then we come back to the breathing in and breathing out way out, easily seen from the side. With a beat within the umbilicus (above and below)


The functional pillars.


With the diaphragmatic exhaust we have seen a thorax mobility with a facial orientation when breathing in and a front orientation when breathing out related to the phrenic centre (the diaphragm’s pillars) But I also said that the fixed point when the contraction is coming (flat thorax) could be positioned in the neighbourhood and in this case the pillars will move as well.


Obviously this is the inferior part of the pillars (attached to the lumbar spine) the superior extremity will move as well. If you compare the diaphragm to an umbrella you can open it vertically or horizontally, it doesn’t matter, the main stick of the umbrella tunes the sticks. Just like an umbrella the membrane works from her bisectors, but the sticks are attached related one to the other to the main stick.


The diaphragm has his horizontal part linked to the press IOP orientation (vertical), but his vertical part is linked to IOP orientation (horizontal). Unlike the umbrella with the diaphragm you cannot change the pillar’s orientation without changing the relation horizontal/vertical part.


With the diaphragm/intercostals/abdominal exhaust we have seen the different interactions that gathered these 3 elements. If you change the pillar’s orientation you will change as well:


The bisectors position.


The intercostals orientation.

The abdominal orientation.


I said it before; the diaphragm digitations need the pillars.


With an asymmetric sagittal way out, the diaphragm’s digitations must find a new combination that will help to contract them better. This is this new combination that I call a functional pillar. And this is at the abdominal level that you may see better the functional pillars. The following images are here to show the crossing over of the oblique and the transverse.


Unfortunately this is done not without changing the thorax/pelvis balance and therefore the transition areas of the rachis. If the pillar is ahead or after the vertical line you will get a anterior or posterior pillar with a potential inversion of the back bend.


But let’s see this from the front.


The pillars and the scoliosis

If there is an important dimension where is it particularly important to centre the anatomical pillars it’s the frontal plan.


The hémithoracic complementarity.


All the digitations are working together in the rising and horizontal part of an hemithorax.

But they have to be opposed to the opposed pillar. Same thing with the hemithorax


This is the thoracic complementarity

Because the centre phrénic doesn’t move. But we know he may move.


The thoracic/asymmetric complementarity.


The thoracic complementarity may damage the hemithoracic complementarity with the flat thorax link to a special breathing schedule.


But with the following image you can directly link the rising parts of the posterior digitations of an hemithorax with the rising anterior parts of the opposed hemithorax.In these conditions the phrenic centre and the pillars will go sideway  forward or backward.


The natural reaction of the rachis will be a side rotation to come back to the balance. The rachis is a powerful tool. But the thoracic muscles as well, much more powerful than the vertebral one.


If you look at the shape and position of the phrenic centre in his relationship to the thorax implantation and the pillars, you should be the signature of a not compensable scoliosis.

This study should lead to a different approach of this phenomenon by considering as a real tool the use of the vertical line to understand better the skeleton malfunction.

Le 21 09 2012.


La gamba.