GENERAL INFORMATION
The posterior cricoarytenoid is an essential muscle located in the larynx. It plays a crucial role in vocal cord abduction, which opens the airway for breathing. It is the only muscle that abducts (moves apart) the vocal cords, making it vital for respiration. Without proper function of the posterior cricoarytenoid, breathing would be impaired. This muscle also assists in controlling voice modulation by adjusting the position of the vocal cords during speech.
ORIGIN
This muscle originates from the posterior surface of the cricoid cartilage, which forms part of the laryngeal framework.
INSERTION POINT
It inserts into the muscular process of the arytenoid cartilage, allowing it to control the movement of the vocal cords.
MAJOR ARTERIES
- Superior Laryngeal Artery: This artery provides the main blood supply to the posterior cricoarytenoid muscle.
- Inferior Laryngeal Artery: Supplements of blood flow to the lower regions of the larynx, including this muscle.
NEURAL INNERVATION
- Recurrent Laryngeal Nerve: A branch of the vagus nerve that innervates the posterior cricoarytenoid muscle, providing the motor control necessary for opening the vocal cords.
TRIGGER POINT
Tension in the posterior cricoarytenoid muscle can result in difficulty breathing, vocal fatigue, or hoarseness. Overuse or misuse of the voice can cause strain, leading to discomfort in the laryngeal area.
CONCENTRIC FUNCTION
During concentric contraction, this muscle shortens and pulls the vocal cords apart (abduction). This action opens the airway, allowing air to pass freely into the lungs during inhalation.
ECCENTRIC FUNCTION
In eccentric contraction, the muscle lengthens while still controlling the movement of the vocal cords. This process aids in closing the vocal cords gently after inhalation, ensuring smooth transitions between breathing and speech.
ISOMETRIC FUNCTION
The posterior cricoarytenoid muscle holds the vocal cords in a stable position during sustained breathing, keeping the airway open without changing muscle length. This function is essential for maintaining clear airflow during activities that require steady breathing, such as talking or singing.
RELATED MUSCLES – SCIENTIFIC NAMES
- Lateral Cricoarytenoid Muscle: Responsible for adducting (closing) the vocal cords.
- Thyroarytenoid Muscle: Helps adjust vocal cord tension and contributes to sound modulation.
- Cricothyroid Muscle: Tenses the vocal cords for higher-pitched sounds.
- Vocalis Muscle: Works with the thyroarytenoid to fine-tune tension in the vocal cords.
ANTAGONIST
- Lateral Cricoarytenoid Muscle: Opposes the posterior cricoarytenoid by adducting the vocal cords, bringing them together during speech.
COMMON INJURIES
- Vocal Cord Paralysis: Injury or dysfunction of the recurrent laryngeal nerve can cause paralysis of the posterior cricoarytenoid, leading to difficulty breathing and a weakened voice.
- Laryngitis: Inflammation of the laryngeal muscles, including the posterior cricoarytenoid, results in hoarseness or temporary voice loss.
- Cricoarytenoid Arthritis: Joint inflammation can cause restricted movement of the posterior cricoarytenoid, leading to difficulty in breathing and voice modulation.
- Muscle Fatigue: Overuse of the posterior cricoarytenoid, particularly in those who speak or sing frequently, can lead to strain and reduced vocal endurance.
- Vocal Cord Dysfunction: Impaired movement of the vocal cords, caused by issues in the posterior cricoarytenoid, can cause breathing difficulties and vocal strain.
EXERCISES
- Deep Breathing Practice: Take slow, deep breaths while focusing on expanding the chest and abdomen. This exercise strengthens the posterior cricoarytenoid by encouraging better control over vocal cord abduction.
- Humming Exercise: Hum softly while exhaling. This exercise helps engage the posterior cricoarytenoid muscle without straining the vocal cords, improving its function during speech.
- Pitch Glides: Start at a low pitch and glide to a higher pitch, then return. This exercise engages the vocal cords, working the posterior cricoarytenoid by promoting smooth transitions.
- Sustained Vowel Sounds: Hold vowel sounds (such as “A” or “O”) for as long as possible, focusing on maintaining consistent airflow. This exercise strengthens the muscles and enhances breath control.
- Vocal Sirens: Mimic, the sound of a siren sliding through different pitches. This exercise stretches the posterior cricoarytenoid, improving its flexibility and range during vocalisation.
STRETCHES
- Neck Tilt Stretch: Slowly tilt your head towards one shoulder and hold for 20-30 seconds. This stretch releases tension in the neck and surrounding muscles, easing the strain on the posterior cricoarytenoid.
- Neck Rotation: Gently rotate your head in a full circle to loosen tight muscles around the larynx. This stretch helps relax the posterior cricoarytenoid and improves vocal control.
- Jaw Stretch: Open your mouth wide and hold for a few seconds, then relax. This stretch relieves tension in the jaw and throat, indirectly benefiting the posterior cricoarytenoid.
- Tongue Stretch: Extend your tongue out as far as possible and hold for 10 seconds. This stretch reduces tension in the base of the tongue, promoting better function of the vocal cords.
- Shoulder Rolls: Slowly roll your shoulders forward and backwards to release tension in the upper body, which can help relax the muscles around the larynx, including the posterior cricoarytenoid.
