Normal mandibular protrusion is greater than how many millimeters?

• A. 0-2 mm
• B. >4 mm (6-9 mm)
• C. 2-4 mm
• D. 8-12 mm

Answer: (B)

Maximal forward movement of the mandible is used to assess TMJ function, and a normal protrusive range is set above a small threshold. The standard cutoff is greater than 4 millimeters, with the typical actual range often around 6–9 millimeters. This means that if a patient can protrude more than 4 mm, their protrusive ROM is considered normal; measurements well below that (0–2 mm or 2–4 mm) indicate reduced ROM and potential dysfunction. While 8–12 mm can occur in some individuals, the defining normal threshold is simply being greater than 4 mm, and the commonly observed range supports 6–9 mm as the typical norm.