GENERAL INFORMATION
The thyrohyoid muscle is a crucial component of the infrahyoid group, positioned in the neck between the thyroid cartilage and the hyoid bone. This muscle is involved in essential functions such as speech and swallowing, as it adjusts the position of the larynx to facilitate these processes. Its activity is particularly important in tasks that require modulation of voice pitch and protection of the airway during swallowing.
ORIGIN
The thyrohyoid muscle is ideally placed to exert influence over the larynx. Originating from the oblique line on the lamina of the thyroid cartilage.
INSERTION POINT
It inserts at the greater horn and the adjacent part of the body of the hyoid bone. This strategic insertion provides leverage that is vital for the elevation of the larynx.
MAJOR ARTERIES
The superior thyroid artery predominantly provides blood supply to the thyrohyoid. This artery plays a crucial role in delivering the necessary nutrients and oxygen required for muscle function and endurance.
NEURAL INNERVATION
The thyrohyoid muscle is uniquely innervated by fibres from the hypoglossal nerve (CN XII), unlike other infrahyoid muscles. This hypoglossal nerve primarily controls tongue movement but also receives contributions from the cervical plexus for muscle innervation. Such specific innervation enables the thyrohyoid muscle to achieve the precise control required for its essential functions.
TRIGGER POINT
Trigger points in the thyrohyoid muscle may lead to discomfort and a sensation of tightness in the anterior neck area, particularly affecting activities like swallowing and speaking. These symptoms are often exacerbated by stress or excessive muscle tension.
CONCENTRIC FUNCTION
In its concentric phase, the thyrohyoid contracts to reduce the space between the thyroid cartilage and the hyoid bone, elevating the larynx. This elevation is crucial during swallowing to prevent aspiration and during speech to adjust voice pitch.
ECCENTRIC FUNCTION
Eccentrically, the muscle controls the downward movement of the larynx after it has been elevated, ensuring a smooth and coordinated return to the resting position. Which is critical for comfortable breathing and readiness for the next speech or swallowing action.
ISOMETRIC FUNCTION
The thyrohyoid also performs isometric contractions, where it stabilises the position of the hyoid and thyroid cartilage during head movements that do not directly involve swallowing or speaking, thus maintaining a steady posture of the larynx.
RELATED MUSCLE-SCIENTIFIC NAMES
- Sternothyroid: Depresses the thyroid cartilage.
- Sternohyoid: Further depresses the hyoid bone.
- Omohyoid: Lowers and stabilises the hyoid bone, complementing the actions of the thyrohyoid.
ANTAGONIST
- Sternothyroid (In Certain Movements): Works in opposition during specific neck movements.
- Stylohyoid: Elevates the hyoid bone, opposing the thyrohyoid’s depression.
- Mylohyoid: Raises the floor of the mouth and hyoid, counteracting thyrohyoid’s depression.
- Geniohyoid: Pulls the hyoid bone forward, contrasting the backward motion facilitated by the thyrohyoid.
COMMON INJURIES
- Muscle Strain: This common injury can occur from overuse, such as extensive speaking or swallowing. Which can lead to pain that affects the quality of voice and ease of swallowing.
- Chronic Tightness: Frequently observed in individuals who experience stress or maintain poor posture for extended periods. Which leads to persistent neck discomfort and functional limitations.
EXERCISES
- Laryngeal Massage: Gently massaging the throat area can help release tension in the thyrohyoid and surrounding muscles, improving flexibility and comfort.
- Gentle Neck Tilts: Tilting the head forward slightly can engage and strengthen the thyrohyoid, supporting better neck and throat health.
- Resisted Neck Flexion: Using the palm to create resistance as the head flexes forward strengthens this muscle, enhancing its function.
- Swallowing Exercises: Practicing controlled swallowing helps to tone and maintain the health of the thyrohyoid. Which is crucial for efficient throat function.
- Vocal Exercises: Engaging in vocal range exercises not only helps train the voice but also strengthens the thyrohyoid muscle, supporting healthy larynx function.
STRETCHES
- Head Lift And Tilt: From a prone position, lifting the head off the ground and gently tilting it forward can effectively stretch the thyrohyoid.
- Neck Rotation: Slowly rotating the head to each side helps stretch and relieve tension in the thyrohyoid and adjacent neck muscles.
- Yoga Neck Extension: Gentle yoga poses that extend the neck can relax and stretch the neck muscles, improving overall flexibility and reducing stress.
- Towel Neck Pull: Using a towel to enhance the forward pull on the head can deepen the stretch in the thyrohyoid, aiding in flexibility and muscle relaxation.
- Controlled Neck Circles: Performing slow and controlled neck circles helps to loosen the entire neck area, promoting blood flow and reducing muscle tightness.