MYLOHYOID

GENERAL INFORMATION

The mylohyoid is a flat, triangular muscle located beneath the jaw. It forms the floor of the mouth and plays an essential role in supporting the tongue, elevating the hyoid bone, and assisting with swallowing and speaking. This muscle is part of the suprahyoid group of muscles, which help stabilise the hyoid bone and control movements of the jaw and tongue. The proper function of this muscle is crucial for efficient swallowing, speech, and maintenance of oral posture.

ORIGIN

This muscle originates from the mylohyoid line of the mandible, which is located along the inside surface of the lower jawbone.

INSERTION POINT

It inserts into the body of the hyoid bone and the midline raphe (a fibrous seam) that runs between the two mylohyoid muscles, providing support to the floor of the mouth.

MAJOR ARTERIES

• Lingual Artery: Provides the primary blood supply to the mylohyoid muscle.

• Submental Artery: This also contributes to blood flow to the mylohyoid and surrounding areas of the jaw and neck.

NEURAL INNERVATION

• Mylohyoid Nerve: A branch of the inferior alveolar nerve (from the mandibular division of the trigeminal nerve, cranial nerve V) provides innervation to the mylohyoid muscle.

TRIGGER POINT

Trigger points in this muscle can cause pain in the lower jaw, tongue, and throat. This trigger point may result in difficulty swallowing, tightness under the chin, or discomfort during speech. Trigger points can also contribute to referred pain in the ear or headaches in the temple region.

CONCENTRIC FUNCTION

During concentric contraction, this muscle shortens to elevate the hyoid bone and the floor of the mouth. This action is essential for initiating the swallowing process by lifting the tongue and pushing food toward the back of the throat.

ECCENTRIC FUNCTION

In eccentric contraction, the mylohyoid muscle lengthens as it controls the lowering of the hyoid bone and the mouth floor after swallowing or speaking. This controlled release helps smooth the transition between swallowing phases and jaw movements.

ISOMETRIC FUNCTION

The mylohyoid muscle maintains tension in a fixed position during isometric contraction, providing stability to the floor of the mouth and the hyoid bone during sustained activities like speaking, swallowing, or holding the jaw in position.

RELATED MUSCLES – SCIENTIFIC NAMES

• Digastric Muscle: Elevates the hyoid bone and assists in opening the mouth.

• Geniohyoid Muscle: Works with the mylohyoid to elevate the hyoid and depress the mandible.

• Stylohyoid Muscle: Elevates and retracts the hyoid bone, aiding in swallowing.

• Hyoglossus Muscle: Depresses the tongue, assisting with speech and swallowing.

ANTAGONIST

• Infrahyoid Muscles: Oppose the action of the mylohyoid by depressing the hyoid bone and controlling its position during swallowing and speech.

COMMON INJURIES

• Mylohyoid Muscle Strain: Overuse of the mylohyoid muscle due to excessive speaking, chewing, or swallowing can lead to strain and discomfort in the lower jaw and neck.

• Temporomandibular Joint (Tmj) Dysfunction: Dysfunction in the TMJ can cause overcompensation by the mylohyoid, leading to tension and jaw pain.

• Difficulty Swallowing (Dysphagia): Strain or dysfunction in the mylohyoid can result in discomfort or difficulty during the swallowing process, impacting food movement down the throat.

• Jaw Pain: Tightness or trigger points in the mylohyoid can lead to pain in the jaw, making it difficult to open or close the mouth.

• Muscle Fatigue: Overuse of the mylohyoid, particularly in individuals who speak or sing for extended periods, can cause muscle fatigue and tightness in the floor of the mouth.

EXERCISES

• Tongue Press Exercise: Press your tongue firmly against the roof of your mouth and hold for 5-10 seconds. This exercise strengthens the mylohyoid muscle, improving swallowing and speech control.

• Jaw Opening Resistance: Place your hand under your chin and press lightly as you try to open your mouth. This exercise engages the mylohyoid and strengthens jaw control.

• Mouth Opening Exercise: Open your mouth as wide as possible, then close it slowly. This exercise works the mylohyoid muscle, promoting better jaw flexibility and strength.

• Neck Flexion Exercise: Lie on your back and gently lift your head towards your chest while engaging the mylohyoid. This exercise strengthens the neck and floor of the mouth.

• Isometric Jaw Hold: Open your mouth halfway and hold the position for several seconds. This isometric exercise strengthens the mylohyoid muscle, improving endurance and stability.

STRETCHES

• Mylohyoid Stretch: Tilt your head back gently while opening your mouth wide. This movement stretches the mylohyoid muscle and releases tension in the floor of the mouth.

• Neck Side Stretch: Tilt your head towards one shoulder and hold for 20-30 seconds. This stretch releases tightness in the mylohyoid and other neck muscles.

• Jaw Stretch: Open your mouth as wide as possible and hold for a few seconds. This stretch helps release tightness in the mylohyoid muscle and surrounding jaw muscles.

• Chin-To-Chest Stretch: Tuck your chin towards your chest and hold for 10-15 seconds. This stretch lengthens the back of the neck and releases tension in the mylohyoid.

• Upper Trapezius Stretch: Gently tilt your head towards one shoulder while pulling the opposite shoulder down. This stretch relieves tension in the upper neck and jaw area, benefiting the mylohyoid muscle.