Diagrammatic illustrations to show the hypothetical effects of compensatory changes in skull dimensions and brain shape when there is craniosynostosis or shortening of certain skull bones.

<p>These figures were created using Adobe Photoshop (<a href="http://www.adobe.com/products/photoshopfamily.html" target="_blank">http://www.adobe.com/products/photoshopfamily.html</a>) which enables manipulation of shapes with fixed points facilitating a simple representation of the distortion. a) Normal; the skull is represented by a black box and brain by a grey circle with reference points w, x, y and z. Asterisk – fixed reference point outside brain. b) Uniform rostrocaudal shortening (black arrows). There is a compensatory increase in height of the brain (white arrow). Lines xy, yz (yellow) and wy (blue) increase and angles wyz and xyz decrease c) Cranial base shortening (black arrow); asymmetrical shortening results in an axial tilting of the brain. There is also a compensatory increase in height (white arrow). Line xy and yz increases (yellow), wy shortens (blue) and angle wyx and xyz decrease. d) Caudal dorsoventral shortening (black arrow). There is a compensatory lengthening of the brain and rostral increase in height (white arrow). Line wy increase (blue), xy and yz shorten (yellow), angle xyz decreases e) cranial base and caudal dorsoventral shortening. When the cranial base and the caudal part of the skull are shortened the circular model brain becomes increasing ellipsoid and there is greater axial tilt with an increase in height rostrally (white arrow). The ventorostral part (olfactory bulbs) is displaced ventrally, the dorsocaudal part (occipital lobes) is displaced caudally and the ventrocaudal part (hindbrain) is displaced rostrally. Line yz shortens and angle xyz decreases. However distance to the external reference point (asterisk) increases (red dotted line). This illustration is offered as an explanation for the increase in line AE and BC in this study and also for the change in brain shape with increasing CM affectedness.