5 minutes on…the Larynx

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Written By Tamra Nathan

The Larynx. A total nightmare to learn about. Still, where would we be without her? Yapping a lot less, that’s for sure.

Gross Overview

  • The larynx is located in the anterior neck

  • Spans the vertebral levels of C3 to C6

  • People often confuse the pharynx and larynx

  • The pharynx leads to the oesophagus, whereas the larynx leads to the trachea

  • So whilst both air and food passes through the pharynx, only air must pass through the larynx, otherwise food would enter your lungs

Function of the Larynx

  • Phonation - voice production

  • Airway protection - prevention of food being aspirated

  • Breathing - allows air to pass to the lungs

The Laryngeal Cartilages

When covering regions of the body, we often cover bones, or osteology, first. However, the larynx has a cartilaginous skeleton - so let’s cover that in 5 minutes instead. Once you have an understanding of the cartilages it will be much easier to build in the knowledge about the ligaments, muscles, nerves and their locations.

The cartilages can be divided into unpaired and paired cartilages.

Unpaired

  • Epiglottic cartilage

  • Thyroid cartilage

  • Cricoid cartilage

Paired

  • Arytenoid cartilages

  • Corniculate cartilages

  • Cuneiform cartilages

laryngeal cartilages depicted together in a hand illustration

Here they all are together as a unit (with the hyoid bone also featured, which is of course, not a cartilage).

cartilages of the larynx, or laryngeal cartilages shown separated in a hand illustrated diagram

And here they are apart.

There are 2 different types of cartilage referenced below in relation to the larynx:

  • Hyaline cartilage - primarily type 2 collagen & proteoglycan, glassy, firm and flexible but less elastic, provides a smooth surface for joint movement

  • Elastic cartilage - contains more elastic fibres, yellowish, flexible, gives structural support whilst also bending

Unpaired Cartilages

depiction of the laryngeal cartilages, with the unpaired cartilages (the epiglottic, thyroid and cricoid)shaded in a rose pink colour

The Epiglottic Cartilage

a diagram of the laryngeal cartilages, with the epiglottic cartilage shaded in pink

  • Elastic cartilage

  • Leaf shaped

  • Attaches to the hyoid bone via the hyoepiglottic ligament, and attaches to the thyroid cartilage via the thyroepiglottic ligament

  • Closes the laryngeal inlet during swallowing - this directs food towards the oesophagus rather than the trachea, and protects you from aspirating

The Thryoid Cartilage

a diagram of the laryngeal cartilages, with the thyroid cartilage shaded in pink

  • Hyaline cartilage

  • Consists of two laminae that meet anteriorly at the laryngeal prominence

  • The posterior borders form the superior and inferior horns (cornua)

  • The inferior horns articulate with the cricoid cartilage to form cricothyroid joints

The Cricoid Cartilage

a diagram of the laryngeal cartilages, with the cricoid cartilage shaded in pink

  • Hyaline cartilage

  • Shaped like a signet ring

  • Forms a complete ring of cartilage around the airway

  • Articulates with the thyroid and arytenoid cartilages

Clinical Relevance - Cricoid Pressure

  • Intubation = tube inserted down the trachea to assist in breathing

  • ‘Cricoid pressure’ may be applied during intubation in patient groups where there is a risk of regurgitated contents coming out of the oesophagus and slipping into the trachea

  • As the cricoid forms a complete ring, putting to pressure on it will push all the way through and compress the oesophagus

Paired Cartilages

a diagram of the laryngeal cartilages, with the paired cartilages (arytenoid cartilage, corniculate cartilage, cuneiform cartilage) shaded in yellow

Arytenoid Cartilages

a diagram of the laryngeal cartilages, with the arytenoid cartilage shaded in yellow

  • Hyaline cartilage, but contain elastic cartilage at the vocal processes

  • Pyramidal shape, with a concave base and articular facet superiorly for the corniculate cartilage

  • It articulates with both the cricoid & corniculate cartilages

  • They have a muscular process for the attachment of the lateral and posterior cricoarytenoid muscles

  • And a vocal process for the vocalis muscle, important for the movement of the vocal cords

Corniculate Cartilages

a diagram of the laryngeal cartilages, with the corniculate cartilage shaded in yellow

  • Elastic cartilage

  • Articulate with the arytenoid cartilage to prolong them posteriorly and medially

Cuneiform Cartilages

a diagram of the laryngeal cartilages, with the cuneiform cartilage shaded in yellow

  • Elastic cartilage

  • Lie within the aryepiglottic folds

a diagram of the laryngeal cartilages, depicting both the unpaired and paired cartilages, the cuneiform cartilage within the epiglottic fold and the hyoid bone in green

Oop - that’s 5 minutes up!

a diagram of the laryngeal cartilages, hand illustrated and labelled

For your next 5 minute session, we suggest…

  • Laryngeal Muscles

  • Laryngeal Ligaments & Folds

  • Laryngeal Vasculature & Innervation

All available in Tamra’s Notes! See you next time x

All original illustrations featured in this blog post are the exclusive intellectual property of the author/creator, Dr Tamra Ariane Nathan. They are protected by copyright laws and must not be copied, reproduced, distributed, altered, or used in any form without the express written permission of the author. Unauthorised use of these illustrations may constitute a violation of intellectual property rights and could result in legal action. If you wish to request permission for usage, please contact the author directly.

Tamra Nathan
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Muscles of Facial Expression, with Terry Jefford.