Intrinsic and Extrinsic Muscles of the Larynx

Intrinsic Muscles of the Larynx

Muscles primarily responsible for sound production and vocal fold control.

• They originate and insert on laryngeal cartilages, allowing for precise adjustments in vocal fold tension and position.

• These muscles are categorized based on their effects on the glottis shape and vocal fold vibratory behavior: adductors, abductors, tensors, and relaxers

Adductors

Muscles that bring the vocal folds together, essential for phonation.

Abductors

Muscles that separate the vocal folds, allowing for breathing.

Tensors

Muscles that stretch and tense the vocal folds, affecting pitch.

Relaxers

Muscles that reduce tension in the vocal folds, allowing for lower pitches.

Lateral Cricoarytenoid

Adducts the vocal folds by rotating the arytenoid cartilages medially.

Transverse Arytenoid

A single (unpaired) muscle that pulls the arytenoids together, aiding in adduction

Oblique Arytenoid

Paired muscle that works in conjunction with the transverse arytenoid to close the glottis (adducting) during phonation.

Posterior Cricoarytenoid (PCA)

The only muscle responsible for abducting the vocal folds, allowing for breathing.

*Please Come Apart*

Cricothyroid

The primary tensor of the vocal folds, adjusting pitch by elongating them.

• Comprised of two parts: Pars Recta and Pars Oblique.

• Pars Recta: Reduces the distance between the cricoid and thyroid cartilages, lengthening and tensing the vocal folds.

• Pars Oblique: Slides the thyroid cartilage forward, contributing to pitch modulation.

Thyrovocalis

Part of the thyroarytenoid muscle that tenses the vocal folds, contributing to pitch control.

Thyromuscularis

Acts as a relaxer, regulating tension and aiding in adduction when necessary.

Thyroarytenoid Muscle

Composed of 2 parts: thyrovocalis (medial) and thyromuscularis (lateral);

• The thyrovocalis is crucial for maintaining the mass of the vocal folds and tensing them during phonation.

• The thyromuscularis can relax the vocal folds when not opposed by other muscles, allowing for lower pitches.

Pars Recta

Part of the cricothyroid muscle that reduces the distance between cricoid and thyroid cartilages.

Pars Oblique

Slides the thyroid cartilage forward, contributing to pitch modulation.

Oblique Interarytenoids

Paired muscles that approximate the arytenoids, aiding in adduction.

Transverse Interarytenoid

Single muscle that approximates the arytenoids, facilitating glottal closure during phonation.

Intrinsic vs Extrinsic Muscles of the Larynx

Intrinsic muscles control the tension and position of the vocal folds, directly affecting voice quality and pitch.

• They work in pairs to achieve medial compression and longitudinal tension, essential for effective phonation.

• Extrinsic muscles support and position the larynx.

Control of Intrinsic Muscles

They control tension and position of vocal folds, affecting voice quality and pitch.

What are the 3 adductors of the larynx

lateral cricoarytenoid

transverse arytenoid

oblique arytenoid

What is the one abductor of the larynx

posterior cricoartynoid (PCA)

Aryepiglottic

Closes laryngeal vestibule

Interarytenoid

Closes posterior commissure of glottis

Extrinsic muscle that depresses the larynx

Omohyoid

Sternohyoid

Sternothyroid

SOS when you’re depressed when you lost your voice

Extrinsic Muscle that elevate the larynx

Digastric (anterior and posterior)

Mylohyoid

Stylohyoid

Thyrohyoid

Shut My Damn Mouth when you lost your voice and youre talking alot