Unfavourable Fracture Mechanics — NDEB AFK MCQ
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Correct answer: A — Horizontally unfavourable fracture
A fracture line running from the inferior border superiorly and posteriorly is horizontally unfavourable because the pull of the elevator muscles (masseter, medial pterygoid, temporalis) on the posterior fragment tends to displace it superiorly, pulling the fragments apart. A horizontally favourable fracture runs from inferior-anterior to superior-posterior, where the muscle forces push the fragments together (resisting displacement). Understanding favourable vs unfavourable fracture mechanics helps determine whether closed or open reduction is needed.
Reference: Hupp – Contemporary Oral and Maxillofacial Surgery, 7th ed., 2019