The Vault

The Cranio-Sacral System

BY Hil Boode


This paper concerns the Cranio-Sacral System (C.S.S.). The ‘cranium’ is the skull, and ‘sacral’ means connected with the sacrum. The explanation of a system is, according to the Longman Dictionary, a group of related parts working together and in the case of our body: the body with its usual ways of working. Besides all the known systems of the body, there is also this C.S.S. To most people, even in the medical world, it is quite unknown.

There are three body structures directly involved in this system:

i . The liquor (central nervous fluid C.N.F.);

ii. The fascia, containing all the interconnected tissues around the nervous system;

iii. All the bones of our body.

The liquor is produced in four interconnected areas—‘the ventricles’—in the centre of the brain. This fluid leaves the fourth ventricle through three small openings and flows into the subarachnoidal space of the meninges and from there along the spinal cord.

The meninges as a part of the fascia consist of a three-layer ‘balloon like’ form of membranes, with a long tail. These meninges cover the brain and the foramen magnum, and from there those three layers continue to surround the spinal cord as far as the second segment of the sacrum. They blend together and are attached to the bone, forming the cauda equina.

All the bones of the body, as I have mentioned before, are influenced by the C.S.S. When we look at the skull, we will see sutures between the different bones. All the more than thirty bones which form the face and skull are hinged together by these sutures. The centre bone is the sphenoid. This bone looks like a bat and forms a big part of the sockets of the eyes. We can only feel a little section of this bone at our temples (from the outside). The sphenoid works together with the sacrum as a unit. This is possible because they are connected by this membrane system. The sphenoid has a cartilageous connection with the occiput and has the ability to make slight movements forward (flexion) and backward (extension). The sacrum has the same sort of ‘joints’ with both ilia, and also moves slightly forward and backward. This happens in the opposite direction from the movement of the sphenoid, having a similar effect as a mirror.

What happens in the C.S.S. is as follows. Liquor fills the meninges, and the head is widening (the body too), the sphenoid goes in flexion, the sacrum flexes too. Then there is a limit of tension in the membranes (meninges) and at that stage the liquor finds its way down along the spinal cord. The reaction of the bones of the head is as follows: they come closer together again. The head becomes longer and less wide. The sphenoid extends, making a motion more in the direction of lengthening of the whole body. This is the forward-and-up direction of the head in our Alexander Technique thinking.

In this situation the sacrum is also extending. From ‘head to tail’ lengthening is taking place. And the whole cycle starts again. This semi-closed hydraulic system of the connected tissues gives the possiblility for this continuing process of widening and lengthening of the body. It is like the ‘breathing’ of the whole body. In normal situations there are between 6 and 10 cycles per minute. The influence on the whole body is caused by the fact that all body fascia is interconnected.

The C.S.S. has amazing consequences, especially because the body is a flexible and moving entity.

Being Alexander teachers we can use the knowledge of this system, and work with it as a tool for understanding, and we can discover when the C.S.S. is partly blocked. In this way we will probably work more effectively, still in our wonderful undoing Alexander manner ‘listening’ to what is taking place. 


Hil Boode had been working as a physical education teacher for several years, when she started her Alexander Technique training at A.T.A. in London in 1980. Since 1983 she has had a practice in Haarlem, Holland. Since attending courses in Cranio-Sacral Therapy in 1986/1987 with Robert Norett MD (U.S.A.) in Holland, she has been integrating her knowledge of the C.S.S. more and more in her work as an Alexander teacher. At present she gives C.S.S. workshops in Haarlem and several other places all over Europe.

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