Fascial Space Infections — MFDS Part 1 MCQ

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ModerateAnatomy (Head & Neck)Fascial Space InfectionsMFDS Part 1

A periapical infection arising from a mandibular third molar perforates the lingual cortical plate below the attachment of the mylohyoid muscle. Which fascial space is most likely to be involved initially?

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Correct answer: D — Submandibular space

The correct answer is D, the submandibular space. The mylohyoid muscle separates the sublingual space above from the submandibular space below. An infection that perforates the lingual mandibular cortex below the mylohyoid attachment therefore enters the submandibular space. Perforation above the mylohyoid line would instead favour the sublingual space. Buccal-space infection follows spread through the buccal cortex. Direct spread to the submental space is uncommon from a third-molar focus and more often occurs secondarily from adjacent spaces. The parapharyngeal space may become involved in advanced deep-neck spread but is not the expected initial space in the anatomical situation described.

Reference: Hoerter JE, Malkin BD. Odontogenic Orofacial Space Infections, section on mandibular odontogenic spread relative to the mylohyoid line, 2023. https://pubmed.ncbi.nlm.nih.gov/36943966/