The mylohyoid line is a prominent anatomic feature that can be found on the inner surface of the mandible (lower jaw bone). It is a bony ridge that runs horizontally along the lower border of the mandible, and it serves as a point of attachment for several important muscles and structures in the head and neck region.
Structure
The mylohyoid line is a linear ridge that is formed by the mylohyoid muscle. This muscle is a thin, sheet-like muscle that is located on the inner surface of the mandible. It originates from the mylohyoid line and inserts into the hyoid bone, which is a U-shaped bone located in the neck that serves as a point of attachment for several muscles of the tongue, larynx, and pharynx.
It is divided into two parts: the superior part and the inferior part. The superior part of the mylohyoid muscle is located above the mylohyoid line and is called the tensor veli palatini. The inferior part of the mylohyoid muscle is located below the mylohyoid line and is called the mylohyoid proper. Both parts of the mylohyoid muscle are innervated by the mylohyoid nerve, which is a branch of the mandibular division of the trigeminal nerve (CN V3).
Location
The mylohyoid line is located on the inner surface of the mandible, and it runs horizontally along the lower border of the mandible from the mental foramen (a small hole in the mandible that allows the mental nerve and vessels to pass through) to the posterior border of the mandible. The mylohyoid line is located just above the alveolar process, which is the bony ridge that supports the teeth.
Function
The mylohyoid line serves as a point of attachment for several important muscles and structures in the head and neck region. These include:
- The mylohyoid muscle: As mentioned above, the mylohyoid muscle is attached to the mylohyoid line, and it plays a crucial role in the movement of the hyoid bone and the larynx. The mylohyoid muscle elevates the hyoid bone and larynx during swallowing and speaking, and it helps to prevent food and liquids from entering the airway.
- The genioglossus muscle: The genioglossus muscle is a thin, flat muscle that is located on the underside of the tongue. It originates from the genial tubercle (a small bump on the inner surface of the mandible) and inserts into the hyoid bone. The genioglossus muscle helps to move the tongue forward during swallowing and speaking.
- The mentalis muscle: The mentalis muscle is a small, triangular muscle that is located on the chin. It originates from the mental protuberance (a small bump on the outer surface of the mandible) and inserts into the skin and subcutaneous tissue of the chin. The mentalis muscle is responsible for elevating the skin and subcutaneous tissue of the chin, which allows for the wrinkling of the skin and the movement of the lower lip.
