The mylohyoid forms the muscular floor of the oral cavity, separating the sublingual space above from the submandibular space below. Its posterior free edge creates the communication between these two spaces — the route by which submandibular abscess can track into the sublingual space (and vice versa) to produce Ludwig's angina. The mylohyoid is dissected in floor-of-mouth surgery and mandibular reconstruction.
| Origin | Mylohyoid line of the mandible (the entire internal oblique ridge from the symphysis to the third molar) |
|---|---|
| Insertion | Fibrous median raphe (anterior two-thirds) and hyoid body (posterior third) |
| Nerve Supply | Mylohyoid nerve (branch of the inferior alveolar nerve, V3) |
| Blood Supply | Mylohyoid artery (branch of the inferior alveolar) and submental artery |
| Actions | Elevates the floor of the mouth and tongue during swallowing; Depresses the mandible when the hyoid is fixed; Elevates the hyoid bone during swallowing |
|---|
Ludwig's angina — bilateral submandibular and sublingual space cellulitis — tracks through the mylohyoid posterior free edge between the submandibular and sublingual spaces, producing the classic brawny induration of the floor of mouth and potential airway compromise. Emergency airway management and aggressive IV antibiotics are required — early awake fibreoptic intubation or surgical airway before swelling occludes the pharynx.
The mylohyoid is palpable as the muscular floor of the mouth by bimanual palpation (one finger intraoral, one extraoral in the submental region).
Mylohyoid space infection spreading between submandibular and sublingual spaces producing airway-threatening floor of mouth cellulitis managed with IV antibiotics and emergency airway.
