Abstract
The mylohyoid ridges or lines are pairs of anatomical bony structures located on the internal or lingual surface of mandible. They are the origin for the mylohyoid muscle. These bony structures are distinct in the mandibular molar region, well protected and gradually become undiscernible towards anterior mandible. Bilateral, isolated fracture of the mylohyoid ridges without concomitant mandibular fracture is rare and, to the best of the authors knowledge, was never previously described. This case report describes an isolated bilateral mylohyoid groove fracture, where one side of a necrotic bone fragment at the fracture site progress to became a nidus of infection, which later caused submandibular space abscess requiring emergency surgical intervention. Diagnosis, possible theory to explain the occurrence of isolated mylohyoid groove fracture and management of these condition are explained in this report.