Torsion

Like flexion and extension, torsion is a physiological movement. Herein, occiput and sphenoid rotate around an anteroposterior axis in the opposite direction. The movement is named according to the rotation of the sphenoidal bone (similar to the way in which the movement of the spinal column is named according to the rotation of the cranial vertebra).

Let us take a rightward rotation for an example. In this movement, the sphenoidal bone rotates to the right; the right greater wing moves upward. Because the joint face of the SBS lies not in a vertical but in a diagonal plane that stretches more or less through the vertex and gnathion, both joint partners make a movement in this diagonal plane (Fig. 4.7). As a result, in a torsion to the right (Fig. 4.8), the basilar part of the occiput moves forward and downward on the right, while the sphenoid body moves upward and backward, and in the opposite direction on the left side.

This has consequences for the occipitoatlantal (OA) joint. On the right side, the occiput moves forward; on the left side, it moves backward. Hence the occiput stands on top of the atlas in a leftward rotation and rightward sidebending.

Since the peripheral bones follow the movement of the central bones, we find the following in the case of a rightward rotation:

• Basilar part anterior and low on the right: right temporal in external rotation (= back right quadrant in external rotation)

• Basilar part posterior and high on the left: left temporal in internal rotation (= back left quadrant in internal rotation)

• Sphenoid body and right greater wing high: front right quadrant in external rotation

• Sphenoid body and left greater wing low: front left quadrant in internal rotation

Torsion Cranial
Outward rotation
Lower Back Wings Muscle

Fig. 4.7a, b a Cranial torsion, b cranial flexion.

Rightward rotation cranial = right I right torsion sacral

Posterior occiput

Greater wing low

Basilar part high

Right Right Sacral Torsion

Sacral position In rightward rotation = R/R

Anterior occiput

Fig. 4.8a-c a, b Rightward torsion and effect on the spinal column and sacrum, c rightward torsion.

Sacral position In rightward rotation = R/R

Rightward rotation cranial = right I right torsion sacral

Posterior occiput

Anterior occiput

Greater wing low

Basilar part high high Basilar part low

Fig. 4.8a-c a, b Rightward torsion and effect on the spinal column and sacrum, c rightward torsion.

Muscle Chain

Consequences for the Pelvis

In a rightward torsion of the skull, the basilar part of the occiput is in flexion on the right, that is, anterior and left posterior, that is, in extension from a craniosacral perspective. Because of this, the dura mater is pulled on the right and is relatively relaxed on the left side. This causes the base of the sacrum to drop on the left and rise on the right. This position corresponds to a rightward torsion around a right axis according to Mitchell's model.

Note: In Sutherland's times, dysfunctions of the sacrum were not named after Mitchell's model.I07- 156 The following terminology was used:

1. Sacrum in flexion

Basis anterior-inferolateral angle (ILA) posterior

2. Sacrum in extension

Basis posterior-ILA anterior

3. Torsion

Basis and ILA anterior or posterior on the same side

4. Sidebending rotation

Basis anterior and ILA posterior on one side, and the other way around on the other side. This corresponds to the sacrum anterior or posterior unilaterally.

The posterior basis of the sacrum provides for the rotation, the lower ILA for the sidebending.

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Responses

  • kristian
    Which muscles help to body right torsion?
    11 months ago

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