Extra-oral examination: skeletal pattern
Orthodontic examination should begin as soon as the patient enters the surgery. The general stage of development, of which statural height is a good indicator, should be noted. The presence of secondary sexual characteristics (Figure 2.1D) also provides a good indication of developmental stage. This chapter will focus on the assessment of skeletal pattern.
The relative position of the maxilla and mandible, termed the skeletal pattern, has a large influence on the relationship of the maxillary and mandibular dentitions. The skeletal pattern should be assessed in three dimensions:
- Anteroposterior (AP);
The aim is to relate the AP position of the mandible to the maxilla and the relationship of these bones to the cranial base. Assessment of the position of each jaw relative to the cranial base gives an indication of which jaw has contributed to any discrepancy. It is important to assess the patient in the natural head position, which is a standardised reproducible head orientation, as the tilt of the head can influence the interpretation of skeletal pattern (Figure 14.1A). To achieve this, the patient should be sitting/>