Routes of spread of odontogenic orofacial infections

Spread occurs along planes of least resistance.
Top panel: Coronal section in the region of the first molar teeth: (a) maxillary antrum; (b) nasal cavity; (c) palatal plate; (d) sublingual space (above the mylohyoid muscle); (e) submandibular space (below the mylohyoid muscle); (f) intraoral presentation with infection spreading through the buccal plates inside the attachment of the buccinator muscle; (g) extraoral presentation to buccal space with infection spreading through the buccal plates outside the attachment of the buccinator muscle.
Bottom panel: Lingual aspect of the mandible: (a) apices of the involved tooth above the myohyoid muscle, with spread of infection to the sublingual space; (b) apices of involved tooth below the mylohyoid muscle, with spread of infection into the submandibular space.