LARYNX

Khaleel Alyahya, PhD, MedKing Saud University@khaleelya

“The larynx is an organ in the neck of humans that involved in breathing, sound

production, and protection of trachea against food aspiration” (Wikipedia)

Definition

Introduction

Specialized organ at the inlet of airpassage.

Superiorly, attached to hyoid bone.

Inferiorly, continues with trachea.

Functions:

Protective sphincter at the air passage.

Phonation.

Regulates passage of air in inspiration andexpiration.

Opens & closes during swallowing,coughing & sneezing.

Cartilage of Larynx

Unpaired (Single) Cartilages

Epiglottis

Thyroid cartilage

Cricoid

Paired Cartilages

Arytenoid

Corniculate

Cuneiform

All cartilages are hyaline

except the epiglottis

elastic cartilage

The framework of the larynx is made up of cartilages.

These cartilages are connected by joints, membranes & ligaments.

Moved by muscles.

Lined by mucous membranes.

Framework of Larynx

Thyroid Cartilage

It is the largest of the laryngeal cartilages.

Formed of two laminae, each has superior &inferior horns.

The angle between two laminae is 90 in male& 120 in female.

It has two notches superior & inferior at themeeting of its two laminae.

Connection of Thyroid Cartilage

Superior: To hyoid bone by thyrohyoid membrane.

Inferior: To cricoid cartilage by the cricothyroid joint & cricothyroid membrane

Epiglottis

Leaf-shaped elastic cartilage.

Lies behind the root of the tongue.

Connected by its stalk to the back of thethyroid cartilage.

Its sides are connected to the arytenoidcartilage by aryepiglottic fold.

Its upper end is free. But its mucous membrane is connected to the back

of tongue by 3 glossoepiglottic folds .. one median& two lateral.

Epiglottis

Cricoid Cartilage Hyaline cartilage.

Ring shaped, having a narrow anterior arch and wide posterior lamina.

Connected superiorly to thyroid cartilage by cricothyroid joint and cricothyroidmembrane.

Arytenoid Cartilage

Paired hyaline cartilage.

Shaped like a 3-sided pyramid.

Its base sits on the superior surface of thecricoid lamina.

Apex: directed superiorly, supports thecorniculate cartilage.

Muscular process directed laterally, givesattachment to three muscles: Posterior & lateral cricoarytenoid.

Thyroarytenoid.

Vocal process: directed forward and givesattachment to the vocal ligament.

Muscles of Larynx Two Major Groups

Extrinsic Muscles – movement of the whole larynx

Elevators: Digastric, stylohyoid, mylohyoid, geniohyoid, stylopharyngeus, salpingopharyngeus & palatopharyngeus.

Depressors: Sternothyroid, sternohyoid & omohyoid.

Intrinsic Muscles - movement within larynx

Control of laryngeal inlet

Control of rima glottidis

Control of length & tension of vocal cords

All intrinsic muscles lie inside the larynx cricothyroid

Cricothyroid Muscle

Origin: Anterior part of arch of cricoid

Insertion: Inferior border & inferior horn of thyroid

Causes flexion at cricothyroid joint

Lengthens & tightens the vocal ligament

Nerve supply: External laryngeal nerve of superiorlaryngeal of vagus.

Muscles Acting on Arytenoids

Posterior cricoarytenoids

Lateral cricoarytenoid

Interarytenoid muscles:

Transverse muscle

Oblique muscle

Thyroarytenoid muscle

Aryepiglottic muscle

Thyroarytenoid & Vocalis Muscles

Action of Intrinsic Muscles

Innervations of Larynx

MOTOR

All muscles of the larynx are supplied by recurrent laryngeal nerve Except Cricothyroid

Supplied by external laryngeal branch of superior laryngeal nerve

SENSORY & SECRETOMOTOR

Above Vocal Cords: Internal laryngeal

Below Vocal Cords: Recurrent laryngeal

Interior of Larynx

It is divided into three parts:

Vestibule: between laryngeal inlet & vestibular fold.

Ventricle: a depression extending laterally between vestibular & vocal folds.

Infraglottic cavity: lies between the vocal fold & lower border of cricoid cartilage.

It is continuous with the trachea inferiorly.

Blood Supply of Larynx

Superior laryngeal artery

branch of superior thyroid artery

Inferior laryngeal artery

branch of inferior thyroid artery

Veins accompany the arteries

Review

Which of the following is not TRUE?

Arytenoid is considered paired cartilage.

All cartilages of larynx are hyaline except cuneiform which is elastic.

Thyroid cartilage is the largest of the laryngeal cartilages.

Most muscles of the larynx are supplied by recurrent laryngeal nerve.

Inferior laryngeal artery is a branch of external carotid artery.

QUESTION?