Topics

Topic

design image
Mylohyoid muscle

The mylohyoid muscle is a thin, flat, triangular muscle forming the floor of the oral cavity. Positioned deep to the mandible and superficial to the geniohyoid muscle, it plays a crucial role in elevating the floor of the mouth and the hyoid bone during swallowing and speaking. Its bilateral arrangement allows the muscles from both sides to meet at the midline, creating the muscular floor of the mouth, essential for oral and pharyngeal functions.

Synonyms

  • Mylohyoideus muscle

  • Floor of mouth muscle (contextual)

Function

  • Elevates the floor of the mouth during the initial phase of swallowing

  • Raises the hyoid bone

  • Assists in depressing the mandible (opening the mouth)

  • Supports the tongue and oral cavity contents

Origin

  • Mylohyoid line of the mandible (internal surface of the body of mandible)

Insertion

  • Median raphe (mylohyoid raphe), a fibrous band extending from the mandible to the hyoid bone

  • Body of the hyoid bone

Nerve Supply

  • Mylohyoid nerve (branch of the inferior alveolar nerve, itself a branch of the mandibular nerve [CN V3], the third division of the trigeminal nerve)

Artery Supply

  • Mylohyoid branch of the inferior alveolar artery (branch of the maxillary artery)

  • Submental branch of the facial artery

Vein Supply

  • Veins correspond to the arteries, mainly draining into the submental vein and the inferior alveolar vein

MRI Appearance

  • T1-weighted images: The mylohyoid muscle appears as an intermediate (isointense) signal structure relative to other muscles.

  • T2-weighted images: Normal muscle demonstrates relatively low signal intensity, but increased signal may indicate edema or pathology. 

  • STIR (Short Tau Inversion Recovery): Shows high signal intensity in cases of edema, infection, or inflammation; otherwise, it appears similar to other muscle tissue.

CT Appearance

  • Appears as a thin, flat, soft tissue band forming the floor of the mouth, distinguishable from adjacent fat and glandular structures by its relatively higher attenuation.

MRI images

Mylohyoid muscle mri axial image