Which statement about MACROGNATHIA is INCORRECT?

Correct answer: B. Affected patients typically have a short mandibular ramus

• A. TRUE. The condylar cartilage is the principal growth site of the mandible. Excessive or prolonged condylar growth — as in ACROMEGALY from a growth hormone-secreting pituitary adenoma, or in condylar hyperplasia — produces mandibular prognathism with a Class III skeletal pattern and anterior crossbite.
• B. CORRECT — this is the FALSE statement. Mandibular macrognathia is characterised by an ELONGATED, not shortened, ramus and body. A SHORT ramus is a feature of MICROGNATHIA and of hypodivergent or condylar-deficient patterns (as in juvenile idiopathic arthritis or hemifacial microsomia). The macrognathic mandible is large in all dimensions.
• C. TRUE. A prominent, protrusive chin button with a concave profile and Class III molar and skeletal relationship is the clinical hallmark.
• D. TRUE. PAGET DISEASE of bone causes disorganised, excessive bone turnover. When it involves the jaws it affects the MAXILLA more often than the mandible, but jaw enlargement, denture no longer fitting, spacing of teeth and hypercementosis are recognised features.

Note: The three big systemic causes of jaw enlargement to keep separate: ACROMEGALY (GH excess after epiphyseal closure — mandibular prognathism, spacing, macroglossia), PAGET DISEASE (older adults, maxilla > mandible, raised alkaline phosphatase, cotton-wool radiopacities), and FIBROUS DYSPLASIA (unilateral, ground-glass, young patients).