GENERAL INFORMATION
The sternothyroid muscle is a crucial component of the infrahyoid group of muscles located in the anterior neck region. It primarily functions to stabilise and depress the larynx, which is vital for phonation as well as swallowing. By controlling the position of the thyroid cartilage, the sternothyroid plays a crucial role in modulating vocal pitch, making it especially important for professional voice users such as singers and speakers.
ORIGIN
The sternothyroid originates from the posterior surface of the manubrium of the sternum. This location is strategically placed to provide optimal leverage for the muscle to perform its functions effectively.
INSERTION POINT
It inserts into the oblique line on the lamina of the thyroid cartilage of the thyroid gland. This insertion allows the muscle to exert direct influence over the positioning of the thyroid cartilage.
MAJOR ARTERIES
The sternothyroid’s primary blood supply comes from the superior thyroid artery, a branch of the external carotid artery. Moreover, This artery ensures that the muscle receives a consistent flow of oxygenated blood, which is necessary for its sustained activity and health.
NEURAL INNERVATION
Neural control of the sternothyroid is provided by the ansa cervicalis, a nerve loop from the cervical plexus, which supplies the motor fibres necessary for the muscle to contract.
TRIGGER POINT
Trigger points in the sternothyroid can lead to sensations of constriction and discomfort in the throat, often mimicking symptoms of an upper respiratory infection. These trigger points may also contribute to changes in voice quality due to the muscle’s influence on the larynx.
CONCENTRIC FUNCTION
When the sternothyroid contracts concentrically, it pulls the thyroid cartilage downward. This action is essential for lowering the pitch of the voice during speech and contributes to the swallowing mechanism by stabilising the larynx.
ECCENTRIC FUNCTION
The eccentric contraction of the sternothyroid allows for a smooth as well as controlled return of the thyroid cartilage to its resting position. This function is crucial after speaking or swallowing, helping to maintain a balanced as well as functional laryngeal posture.
ISOMETRIC FUNCTION
Isometric contraction occurs when the sternothyroid muscle maintains a constant length while exerting force. This function stabilises the thyroid cartilage during various neck movements and other activities that do not require active depression of the larynx but do require its positional stabilisation.
RELATED MUSCLE-SCIENTIFIC NAMES
- Sternohyoid: Another infrahyoid muscle that depresses the hyoid bone.
- Thyrohyoid: Shortens the distance between the thyroid gland and the hyoid bone, coordinating with the sternothyroid.
- Omohyoid: Assists in lowering the hyoid bone and stabilising the lower neck.
ANTAGONIST
- Cricothyroid: Tenses and elongates the vocal cords by tilting the thyroid cartilage forward.
- Thyrohyoid (In Some Movements): Elevates the thyroid cartilage slightly, opposing the sternothyroid.
- Digastric (Anterior And Posterior Belly): Elevates the hyoid bone, counteracting the depression caused by the sternothyroid.
COMMON INJURIES
- Muscle Strain: This is particularly common in professions that demand extensive voice use, where it manifests as pain and a potential decrease in vocal range or a change in voice quality.
- Chronic Tightness: Often seen in individuals with poor ergonomic practices, leading to persistent discomfort and limitation in neck mobility. Which can affect daily activities.
EXERCISES
- Gentle Neck Flexion: Slowly bend the head forward, helping to activate and strengthen the sternothyroid.
- Neck Extension: By gently tilting the head backwards, this stretch can help counteract the typical movements of the muscle, providing relief.
- Resisted Neck Flexion: Place a hand against the forehead, providing resistance as you attempt to flex the neck forward, strengthening the muscle.
- Yoga Shoulder Stands: An inverted position that extends the neck, engaging the sternothyroid muscle indirectly.
- Throat Massage: Applying gentle massage around the neck can help reduce muscle tightness and improve circulation.
STRETCHES
- Forward Head Tilt: Encourages a stretch in the sternothyroid by bringing the chin towards the chest.
- Lateral Neck Stretch: Stretch the neck muscles on one side by tilting your head and bringing your ear towards your shoulder.
- Diagonal Neck Stretch: Combining lateral tilt with rotation, this stretch targets different muscle fibres of the neck.
- Dynamic Neck Rotations: Rotate the head in a controlled circular motion to improve flexibility and circulation in the neck muscles.
- Towel-Assisted Neck Stretch: Use a towel to enhance the stretch by pulling the head gently forward and focusing on the front neck muscles.