STERNOHYOID

GENERAL INFORMATION

The sternohyoid muscle, part of the infrahyoid group, lies in the anterior neck and primarily aids in swallowing and speech by stabilising and lowering the hyoid bone and larynx. This slender muscle is vital for neck movement coordination, contributing significantly to throat function mechanics. Understanding its role enhances insights into basic neck anatomy and its involvement in essential daily activities such as eating and talking.

ORIGIN

The sternohyoid originates from two specific sites: the posterior surface of the manubrium of the sternum and the medial end of the clavicle. This dual origin provides the muscle with a firm attachment that facilitates its actions on the hyoid bone.

INSERTION POINT

This muscle inserts along the lower margin of the hyoid bone. Its insertion gives it leverage to effectively pull the hyoid bone downwards, which is essential during the swallowing process.

MAJOR ARTERIES

The blood supply to the sternohyoid is secured through the superior thyroid artery, with smaller contributions from the infrahyoid artery. These arteries ensure that the muscle receives the necessary nutrients and oxygen to function.

NEURAL INNERVATION

Innervated by the ansa cervicalis, which is a loop of nerves derived from the cervical plexus, the sternohyoid receives the motor commands necessary for its contraction. This neural supply is critical for the coordinated movement of the hyoid bone.

TRIGGER POINT

The presence of trigger points in the sternohyoid muscle can lead to symptoms that mimic throat disorders, such as difficulty swallowing, a sensation of tightness, and even mild hoarseness. These symptoms often result from muscle tension or overuse.

CONCENTRIC FUNCTION

The sternohyoid contracts concentrically to depress the hyoid bone and larynx, an action crucial during the swallowing process. This contraction helps to regulate the opening of the oesophagus and ensures that food is directed towards the stomach.

ECCENTRIC FUNCTION

Eccentric contraction of the sternohyoid occurs as the hyoid bone and larynx return to their resting positions after being depressed. This controlled movement is essential for the smooth completion of swallowing and resetting of the voice box.

ISOMETRIC FUNCTION

During various head and neck movements that do not involve changing the position of the hyoid bone, the sternohyoid contracts isometrically to stabilise and maintain the position of the hyoid. This function is vital for activities that require vocalisation and precise neck movements.

RELATED MUSCLE-SCIENTIFIC NAMES

• Sternothyroid: Helps in the depression of the thyroid cartilage.
• Omohyoid: Assists in lowering the hyoid and stabilising the lower neck.
• Thyrohyoid: Adjusts the distance between the thyroid cartilage and hyoid bone.

ANTAGONIST

• Digastric: Raises the hyoid bone and assists in jaw opening.
• Mylohyoid: Elevates the floor of the mouth during the initial phase of swallowing.
• Geniohyoid: Pulls the hyoid bone forward during swallowing.
• Stylohyoid: Elevates and retracts the hyoid bone.

COMMON INJURIES

• Muscle strain: This injury may result from sudden forceful movements or overstretching during activities, causing immediate neck pain and restricted movement.
• Chronic neck tension: Prolonged poor posture, particularly in individuals who work for long hours at desks, can lead to chronic tension and pain in the sternohyoid and surrounding muscles.

EXERCISES

• Neck tilt against resistance: Using the palm against the forehead, actively push forward while resisting with the neck muscles to strengthen the sternohyoid.
• Chin tuck: Draw the chin directly backwards, which engages the sternohyoid and improves the postural alignment of the neck.
• Neck rotation resistance: While pressing the hand against the side of the face, try to rotate the head against this resistance to enhance muscle engagement.
• Isometric hold: Push the forehead into the palm without moving the head to increase muscle endurance.
• Forward neck stretch: By gently pressing the chin toward the chest, this movement stretches the sternohyoid, alleviating tightness and enhancing flexibility.

STRETCHES

• Gentle neck extension: Slowly arching the neck backwards can effectively stretch the sternohyoid, relieving tension in the anterior neck.
• Lateral neck stretch: Tilt the head to the shoulder to stretch the sternohyoid on the opposite side, which can help reduce stiffness.
• Towel neck pull: Wrap a towel around the back of the head and gently pull the head forward to intensify the stretch in the sternohyoid.
• Cross-body neck stretch: Look toward an armpit while tilting the head down to engage a deeper stretch in the muscle.
• Dynamic neck circles: Rotate the head slowly in a full circular motion to relax and stretch the neck muscles comprehensively.