GENERAL INFORMATION
The suprahyoid muscles are a group of four small muscles located above the hyoid bone in the neck. These muscles play a crucial role in elevating the hyoid bone, assisting with swallowing, speech, and tongue movement. The suprahyoid group includes the digastric, mylohyoid, geniohyoid, and stylohyoid muscles. Together, they work to stabilise the hyoid bone and assist in lowering the mandible, playing an essential role in oral functions and maintaining neck posture.
ORIGIN
- Digastric muscle: The anterior belly originates from the digastric fossa of the mandible, and the posterior belly originates from the mastoid notch of the temporal bone.
- Mylohyoid muscle: Originates from the mylohyoid line of the mandible.
- Geniohyoid muscle: Originates from the inferior mental spine of the mandible.
- Stylohyoid muscle: Originates from the styloid process of the temporal bone.
INSERTION POINT OF SUPRAHYOID
- Digastric muscle: Inserts into the hyoid bone via an intermediate tendon.
- Mylohyoid muscle: Inserts into the hyoid bone and midline raphe (a fibrous seam in the middle of the muscle).
- Geniohyoid muscle: Inserts into the body of the hyoid bone.
- Stylohyoid muscle: Inserts into the hyoid bone of its body.
MAJOR ARTERIES
- Lingual artery: Supplies blood to the mylohyoid, geniohyoid, and stylohyoid muscles.
- Facial artery: Provides blood to the digastric and stylohyoid muscles.
- Submental artery: Contributes blood flow to the mylohyoid and geniohyoid muscles.
NEURAL INNERVATION
- Digastric muscle: The anterior belly is innervated by the mylohyoid nerve (a branch of the mandibular nerve), and the facial nerve innervates the posterior belly.
- Mylohyoid muscle: Innervated by the mylohyoid nerve.
- Geniohyoid muscle: Innervated by the hypoglossal nerve (cranial nerve XII).
- Stylohyoid muscle: Innervated by the facial nerve (cranial nerve VII).
TRIGGER POINT
Trigger points in the suprahyoid muscles can lead to jaw pain, difficulty swallowing, or a sensation of tightness in the throat. These trigger points may also contribute to temporomandibular joint (TMJ) dysfunction, causing discomfort during chewing or speaking.
CONCENTRIC FUNCTION
In concentric contraction, the suprahyoid muscles shorten, elevating the hyoid bone and the floor of the mouth. This action assists in swallowing by creating space for food to pass through the throat and facilitates tongue movement during speech.
ECCENTRIC FUNCTION
During an eccentric contraction, the suprahyoid muscles lengthen as they control the lowering of the hyoid bone and jaw, helping maintain smooth, controlled movements when speaking or opening the mouth.
ISOMETRIC FUNCTION
The suprahyoid muscles stabilise the hyoid bone in a fixed position during activities such as prolonged speaking, chewing, or swallowing, ensuring proper alignment and function of the surrounding structures.
RELATED MUSCLES – SCIENTIFIC NAMES
- Infrahyoid muscles: Work with the suprahyoid muscles to stabilise the hyoid bone.
- Masseter muscle: Assists in closing the jaw during chewing.
- Temporalis muscle: Elevates and retracts the jaw.
- Hyoglossus muscle: Controls tongue movement, aiding speech and swallowing.
ANTAGONIST
- Infrahyoid muscles: Oppose the suprahyoid muscles by depressing the hyoid bone and controlling its position during speech and swallowing.
COMMON INJURIES
- TMJ Dysfunction: Dysfunction in the temporomandibular joint can overwork the suprahyoid muscles, leading to tension and discomfort during chewing or speaking.
- Swallowing Difficulties: Injury or strain to the suprahyoid muscles can affect swallowing, causing discomfort or a feeling of tightness in the throat.
- Muscle Tightness: Stress or poor posture may cause the suprahyoid muscles to tighten, leading to neck stiffness and jaw pain.
- Neck Strain: Sudden movements or excessive strain on the suprahyoid muscles can lead to discomfort and restricted neck and jaw movement.
- Tension Headaches: Tightness in the suprahyoid muscles can contribute to tension headaches, particularly when jaw and neck muscles are overused.
EXERCISES
- Tongue Press Exercise: Press your tongue firmly against the roof of your mouth and hold for 5-10 seconds. This exercise strengthens the suprahyoid muscles, improving swallowing and speech control.
- Jaw Resistance Exercise: Place your hand under your chin and lightly press upward while trying to open your mouth. This exercise strengthens the suprahyoid muscles by activating them during jaw movement.
- Neck Flexion Exercise: Lie on your back and lift your head slightly off the ground, engaging the suprahyoid muscles to stabilise the hyoid bone while flexing the neck.
- Isometric Chin Tuck: Sit with a straight back and tuck your chin towards your chest, holding for a few seconds. This exercise targets the suprahyoid muscles while strengthening the neck muscles.
- Mouth Opening Resistance: Place your thumb under your chin and gently apply resistance as you slowly open your mouth. This exercise engages the suprahyoid muscles and improves their strength.
STRETCHES
- Suprahyoid Stretch: Sit or stand with a straight back and open your mouth wide while extending your chin upwards. This movement stretches the suprahyoid muscles and releases tension in the neck and jaw.
- Neck Side Stretch: Tilt your head gently to one side and hold for 20-30 seconds. This stretch releases tightness in the suprahyoid and adjacent neck muscles.
- Chin Tuck Stretch: Tuck your chin towards your chest and hold for 10-15 seconds to stretch the back of the neck, releasing tension in the suprahyoid area.
- Jaw Stretch: Open your mouth as wide as possible, hold for a few seconds, then slowly close. This stretch helps release tension in the suprahyoid and jaw muscles, improving flexibility.
- Neck Extension Stretch: Tilt your head backwards and look upwards, holding the position for 15-20 seconds. This movement stretches the front of the neck, including the suprahyoid muscles.