What is a key feature of a skeletal posterior crossbite?

A key feature of a skeletal posterior crossbite is the presence of a high palatal vault. This anatomical characteristic indicates that the maxillary arch is relatively narrow and elevated, which can contribute to the relationship between the mandible and maxilla being skewed. When the palatal vault is high, it can predispose the occlusal surfaces of the molars to align in a way that causes the maxillary molars to be positioned more lingually, resulting in a crossbite.

In skeletal posterior crossbites, this skeletal relationship is typically due to underlying issues in growth or development, rather than simply a dental alignment issue that might be seen in a dental crossbite. Therefore, the high palatal vault is a crucial feature that distinguishes skeletal posterior crossbites from other types of crossbites, emphasizing the skeletal dimension over just dental positioning.

Understanding the rationale for this feature is essential since treatment approaches may vary significantly based on the underlying skeletal versus dental causes. For example, addressing a high palatal vault may involve orthopedic appliances to widen the arch and correct the crossbite, while other conditions may require different orthodontic strategies.