[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Mylohyoid [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Mylohyoid The mylohyoid is a sheet of muscle that forms the floor of the mouth; it lifts the floor of the mouth and the tongue when swallowing. Official name: Mylohyoid muscle [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=mylohyoid&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A sheet of muscle forming the floor of the mouth. ## What it does Lifts the floor of the mouth and the tongue when swallowing. ## Key points - The muscular floor of the mouth: it separates the sublingual space above from the submandibular space below, which communicate around its free posterior border - The mylohyoid line slopes down toward the front: roots of the lower second and third molars lie below it, so their infections spread to the submandibular space; premolar infections spread above it - Ludwig angina: a fast-spreading cellulitis of the submandibular and sublingual spaces on both sides, usually from a lower molar; the [tongue](https://durgical.com/en/anatomy/tongue/) is pushed up and back and the airway is at risk ## Key facts **Origin** Mylohyoid line of the [mandible](https://durgical.com/en/anatomy/mandible/) **Insertion** Midline raphe and body of the hyoid **Action** Raises the floor of the mouth and the hyoid; depresses the mandible **Nerve** Nerve to mylohyoid (V3) **Blood supply** Submental artery, mylohyoid branch of the inferior alveolar artery ## Relations **Above** [Geniohyoid](https://durgical.com/en/anatomy/geniohyoid-muscle/), [genioglossus](https://durgical.com/en/anatomy/genioglossus-muscle/) and [hyoglossus](https://durgical.com/en/anatomy/hyoglossus-muscle/); the [sublingual gland](https://durgical.com/en/anatomy/sublingual-gland/), the submandibular duct, the [lingual nerve](https://durgical.com/en/anatomy/lingual-nerve/) and the [hypoglossal nerve](https://durgical.com/en/anatomy/hypoglossal-nerve/) lie on its oral surface **Below** Anterior belly of the [digastric](https://durgical.com/en/anatomy/anterior-belly-of-digastric-muscle/), the superficial part of the [submandibular gland](https://durgical.com/en/anatomy/submandibular-gland/), the [facial artery](https://durgical.com/en/anatomy/facial-artery/) and vein, and the submental lymph nodes **Behind** Free posterior border: the submandibular gland hooks round it, with its deep part and duct above the muscle, and the hypoglossal nerve passes deep to it into the floor of the mouth **Medial** Joins its partner at a midline raphe running from the chin to the [hyoid bone](https://durgical.com/en/anatomy/hyoid-bone/) ## How to find it It is not felt as a separate muscle: pressing up under the chin while the person swallows gives the firm floor of the mouth. In surgery it appears once the anterior belly of the digastric is retracted; pulling its posterior border forward exposes the lingual nerve, the submandibular duct and the hypoglossal nerve. ## Examination - Bimanual palpation of the floor of the mouth, one gloved finger inside and the other hand under the jaw, with the muscle between them: used to feel a stone in the submandibular duct, an enlarged gland or a mass in the sublingual or submandibular space ## On imaging Coronal CT or MRI shows it as a sling from the mylohyoid line of each side to the hyoid: the sublingual space lies above it, the submandibular space below. Contrast CT is chosen in Ludwig angina or a dental abscess to map spread around its free posterior border and to find gas or a drainable collection. A plunging ranula passes from the sublingual space through or behind it. ## Clinical notes - In Ludwig angina the swelling is woody and the floor of the mouth rises; airway control comes first, before draining the spaces - Gaps in the muscle let sublingual gland tissue or a ranula pass into the neck (plunging ranula) - In submandibular gland excision it is retracted forward to reach the deep part of the gland, the duct and the nerves above it ## Anatomical variants - Defects (hiatuses) in its front part are common; sublingual gland tissue or fat may bulge through them and mimic a mass under the jaw ## Development From the first pharyngeal arch, like the anterior belly of the digastric, which is why both receive the nerve to mylohyoid. ## Related conditions - [Deep neck infection and Ludwig angina](https://durgical.com/en/conditions/deep-neck-infection-and-ludwig-angina/) ## Test yourself Think of the answer, then tap the question to see it. ## Which two spaces does the mylohyoid separate, and where do they communicate? The sublingual space above from the submandibular space below; they communicate around its free posterior border. ## Why do infections of the lower second and third molars spread to the submandibular space? Their roots lie below the mylohyoid line, which slopes down toward the front; premolar infections spread above it. ## What is Ludwig angina and what is the first priority in its management? A fast-spreading cellulitis of both submandibular and sublingual spaces, usually from a lower molar; airway control comes first, before drainage. ## Which nerve supplies the mylohyoid? The nerve to mylohyoid (V3), as the muscle comes from the first pharyngeal arch, like the anterior belly of the digastric. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/mylohyoid-muscle/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** musculus mylohyoideus TA2 2165 **Official Spanish (DeCS)** Músculo milohioideo **English (TA2)** Mylohyoid muscle ## Related - [Submandibular gland](https://durgical.com/en/anatomy/submandibular-gland/) - [V3 mandibular](https://durgical.com/en/anatomy/anterior-division-of-mandibular-nerve/) Sources: Terminologia Anatomica (TA2); [Anatomy, Head and Neck, Mylohyoid Muscle](https://www.ncbi.nlm.nih.gov/books/NBK545293/); [Anatomy, Head and Neck: Suprahyoid Muscle](https://www.ncbi.nlm.nih.gov/books/NBK546710/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/mylohyoid-muscle/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/mylohyoid-muscle/