Table 1 Classification of hemifacial microsomia by Pruzansky (1969)

I

All the elements of the mandible exist

Various degree of hypoplasia of mandible

Decrease of cartilage and articular cavity size of the temporomandibular joint

Normal hinge movement with mouth opening limitation

All masseteric muscles are in low volume but in normal range

IIA

Abnormal shape of articular structure

The head of the condyle is cone shape and anterior than normal position

The coronoid process and gonial angle are normal

Temporomandibular joint is able to move in hinge axis but translation is impossible

All masseteric muscles exist but are in hypotrophy

II B

No articulation exists between the condyle and temporal bone

Various sizes of coronoid process

Possible abnormal position of the condyle

Various defects of pterygoid and masseter muscles

No adhesion of lateral pterygoid muscles to the mandible

III

Deficiency of the mandibular ramus

Significant hypotrophy of masseteric muscles

No adhesion of lateral pterygoid and temporalis muscles to the mandible