An impacted mandibular third molar can be displaced into the submandibular space during its surgical removal when the

bone on the lingual surface is fenestrated inferior to the mylohyoid muscle.

buccal cortical bone in the mandibular third molar area is extremely thin.

roots of the mandibular third molar lie close to the buccal cortex.

attachment of the mylohyoid muscle is inferior to the level of the roots.