The present investigation was based on the cephalometric analysis of lateral teleroentgenographic pictures of 48 ten-year-old boys with complete unilateral clefts of the lip and palate. Using cluster and factor analysis, the author investigated the relationships among 75 craniofacial size, shape and position characteristics. Both multivariation methods proved useful in the search for associations between partial cranial structures. They supplemented each other well, and their combined use contributed to the definition of the following basic and specific principles of craniofacial relations and compensatory and adaptive mechanisms in patients with clefts. The maxilla consists of two mutually almost independent parts. The vertical parameters of the anterior upper face are interrelated with the slope of the palate plane; the dentoalveolar component of the upper jaw is formed independently. This fact can be aptly explained by the effect of orthodontic treatment, which contributes substantially to an improvement of the facial configuration. Rotation of the mandible has an impact on the vertical dimensions of the anterior lower, as well as the whole, face and is closely associated with the position of the mandibular body but not with the posi- tion of its branch nor with its length. The slope of the mandibular branch correlates with the mental angle, with the gonial angle and the slope of its dentoalveolar component, which is the result of adaptation to a shortening of the maxilla while preserving a positive overjet. Damage to the sagittal intermaxillary and interalveolar relations is pri- marily due to a reduction in the depth of the maxilla and is associated with the length of the mandibular body, while no relation with its rotation or length of the ramus was found. Solution of the given problem may help to find predictive models of facial development in patients with clefts.

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