ByDr. Musaed Al Fayez

Specialized organ at the inlet of air passage.

Function: 1- Protective

sphincter at the air passage.

2- Phonation. 3- Regulates passage

of air in inspiration and expiration.

4- Opens & closes during swallowing, coughing & sneezing.

Unpaired cartilages Epiglottis Thyroid cartilage Cricoid

Paired cartilages Arytenoid Corniculate Cuneiform All cartilages are

hyaline except the epiglottis (elastic)

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.

The Laryngeal cartilage are Nine

3 single & 3 Paired

Single: Thyroid Cricoid Epiglottis.

Paired: Arytenoids Corniculate Cuneiform.

Thyroid Cartilage

It is the largest of the laryngeal cartilage.

Formed of 2 laminae, each has superior & inferior horn.

The angle between 2 laminae is 90 in male & 120 in female.

It has 2 notches superior & inferior at the meeting of its 2 laminae.

Connection of the 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 the thyroid cartilage.

Its sides are connected to the arytenoid cartilage 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 & 2 lateral.

Cricoid cartilage: Hyaline. Ring shaped, having a narrow anterior arch and wide

posterior lamina. Connected superiorly to thyroid cartilage by cricothyroid

joint and cricothyroid membrane.

Arytenoid cartilage: Paired hyaline cartilage. Shaped like a 3- sided

pyramid. Its base sits on the superior

surface of the cricoid lamina. Apex: directed superiorly,

supports the corniculate

cartilage. Muscular process directed

laterally, gives attachment to 3 muscles:

Posterior & lateral cricoarytenoid.

And Thyroarytenoid. Vocal process: directed

forward and gives attachment to the vocal ligament.

2 Major groups Extrinsic Muscles: ( move 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 All intrinsic muscles lie inside the larynx cricothyroid

Origin: Anterior part of arch of cricoid Insertion: Inferior border & inf. Horn of thyroid Causes flexion at cricothyroid joint Lengthens & tightens the vocal ligament Nerve supply: External laryngeal nerve of

superior laryngeal of vagus.

Posterior cricoarytenoid is the only abductor of the vocal cords.

Posterior cricoarytenoids

Lateral cricoarytenoid

Interarytenoid muscles: Transverse & Oblique

Thyroarytenoid muscle

Aryepiglottic muscles

MOTORAll muscles of the larynx are supplied the

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

The interior of the larynx

It is divided into 3 parts:

1- vestibule: between laryngeal inlet & vestibular fold.

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

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

It is continuous with the trachea inferiorly.

Superior laryngeal artery – branch of superior thyroid artery

Inferior laryngeal artery – branch of inferior thyroid artery

Veins accompany the arteries