The Larynx

The Hypopharynx

The Oropharynx

To describe the laryngeal skeleton & membranes

To analyze the function of laryngeal parts in relation

to its anatomy.

To describe oro- & hypo-pharynx

Case scenario …

A 40 years old female teacher consulted

the ENT surgeon for change in her voice

which became hoarse over the last few

weeks, hoarseness was interrupted by

periods where she looses her voice

completely, there was also laryngeal

discomfort & attacks of dry cough.

Fibreoptic laryngoscopy showed a big

polyp in her left cord.

Decision for excision of this polyp was

made by direct laryngoscopy.

The larynx:

-A cartilaginous structure that serves as a

passageway for air between the pharynx and

the trachea

-Lies in the anterior midline (C4-C6)

-Upper part is triangular in section

-Lower part is rounded in section

Ph

Relations:

*Anterolaterally; Thyroid gland & strap muscles

*Laterally; Carotid sheath

*Posteriorly; Pharynx

Functions:

1- Valve action; during

swallowing.

2- Phonation.

3- Building intra-abdominal

pressure.

4- Respiration.

1 2

3 4

Single Pair

1 Thyroid 4 Arytenoid

2 Cricoid 5 Corniculate

3 Epiglottis 6 Cuneiform

1

1

1

2 2

2

3

3

3

4 4

Laryngeal cartilages:

The thyroid cartilage:

•Two quadrilateral laminae meet in the midline

•The meeting angle is 90O in male & 120O in female (Adam’s apple)

•The cartilage articulates by its inferior horns with the cricoid cartilage

Parts of the thyroid cartilage:

The cricoid cartilage:

•It is the lowest part of larynx (C6 level)

•Ring-like with anterior arch & posterior broad

lamina

•It provides two pairs of synovial joints:

1- For the inferior horns of thyroid cartilage;

on each side.

2- For the arytenoids; on the lamina.

arch

lamina

2

1

Joints (synovial):

1- Cricothyroid; permits rocking movement

of thyroid on cricoid (forward & backward

bending).

2- Cricoarytenoid; permits sliding &

rotation of the arytenoid on cricoid lamina.

1

2

The arytenoid cartilage:

•Three sided pyramid

•The base sits on the cricoid shoulder &

carries three processes, two are

important:

1- The anterior (vocal) process: for vocal

cord

2- The lateral (muscular) process: for

muscles

1 2

1 2

The epiglottis:

•Elastic, leaf-like cartilage

•Attached by its base to the back of the thyroid

cartilage in the midline

•Its upper part stands behind the posterior third

of the tongue

•Attached by its sides to the arytenoids by the

quadrate membrane

The quadrate membrane:

Has four borders:

1- Anterior; to the epiglottis

2- Posterior; to the arytenoids

3- Upper; free, called ary-epiglottic fold

4- Lower; free, called vestibular fold (false cord)

3

4

Laryngeal membranes:

The thyro-hyoid membrane:

-From upper border of thyroid cartilage to

the hyoid bone

-Forms the lateral boundary of the

pyriform recess

The pyriform recess:

-Lies between the thyrohyoid membrane

laterally & quadrate membrane medially.

-It is outside the laryngeal cavity

-It is common site for fishbones & foreign

bodies lodgement

The conus elasticus:

-Is ½ a cylinder

-Lower attachment to cricoid arch

-The ends of the free upper border are attached to the vocal processes of the

arytenoid forming the vocal cord

-Anterior attachment to the thyroid cartilage

-Movement of arytenoids on the cricoid cartilage will move the vocal cords

Laryngeal inlet:

Is an inverted vertical triangle:

•Base; epiglottis

•Sides; ary-epiglottic folds

The cavity of the Larynx

The vestibule:

-The distance from inlet to vocal cords

-Lies between the two quadrate membranes

-Features:

1- The vestibular folds

2- The laryngeal ventricle; mucosal hernia

between the true & false cords

1

2

The vocal folds:

-The anterior 3/5 (conus)

-Posterior 2/5 (vocal process)

-Vocalis; muscle fibers in the vocal cord,

increases the apposed surface area

-Rima glottidis; openings between the cords

-Glottis ; laryngeal diameter at the level of the

vocal cords

The rima glottidis:

-Is 23 mm long in male & 17 mm in female

Movements:

1- Phonation; cords are just touching each other.

2- Quite respiration; V shape opening, by sliding of the arytenoids on the

cricoid lamina.

3- Forced respiration; diamond shape opening, by rotation of the arytenoids on

the cricoid lamina.

1 2 3

Act on vocal cords Act on inlet

Tension Sphincteric Sphincteric

Shorten Lengthen Open Close Open Close

Thyroarytenoi

d (6)

Cricothyroid

(5)

Posterior

crico-arytenoid

(4)

Transverse

arytenoid (2) Elastic

recoil

Aryepiglottic

(1) Lateral crico-

arytenoid (3)

1

2

3 4

6 5

Laryngeal muscles

Arteries of the larynx:

1- Superior laryngeal artery;

-From the superior thyroid artery

-Pierces the thyrohyoid membrane to lie in the

floor of the pyriform recess

-Supplies the supraglottic part

2- Inferior laryngeal artery;

-From the inferior thyroid artery

-Enters the larynx deep to the inferior

pharyngeal constrictor

-Supplies the glottic & infraglottic parts

Veins accompany arteries

Nerves of the larynx:

Motor:

All muscles of the larynx are supplied by the

recurrent laryngeal nerve except cricothyroid

(external laryngeal nerve)

Sensory:

•Supraglottic part: internal laryngeal nerve

•Infraglottic & glottic parts: recurrent laryngeal

nerve

The laryngopharynx:

•The part of the pharynx opposite to

laryngeal inlet

•It is characterized by:

1- One median glosso-epiglottic fold

2- Two lateral glosso-epiglottic folds

3- The valleculae; on each side of the

median glosso-epiglottic fold

4- The pyriform recess

2 2

4 4

2

4

2

1

4

3 3

The oropharynx:

•The part of the pharynx behind the oral

cavity

•Limited anteriorly by the palatoglossal

fold

•Supplied by pharyngeal branch of IX

•Structures in this part are:

1- Faucial pillars (palatoglossal &

palatopharyngeal folds)

2- Lingual tonsils

3- Palatine tonsils

2

1 3

1

The palatine tonsils:

•Lie between the 2 pillars (tonsillar fossa)

•The part above it is called supratonsillar

recess

•Characterized by surface crypts

•Surrounded by tonsillar capsule

•Supplied by branches from facial, palatine

& pharyngeal arteries

chronic acute

Tonsillitis