Anatomy of the larynx and trachea

3,260views

00:00 / 00:00

Notes

Figure 1: Cartilaginous skeleton of the Larynx and Trachea A. anterior view and B. posterior view.
Figure 2: Cartilaginous skeleton of the Larynx and Trachea A. lateral view and B. with hemisected thyroid cartilage.
Figure 3: Neurovasculature of the Larynx and trachea A. Arteries and nerves and B. veins.
Figure 4: the Laryngeal cavity, mid-sagittal view.
Figure 5: Anatomy of the vocal Ligaments, superior view A. superficial and B. deep.

Muscle
Origin
Insertion
Innervation
Action
Cricothyroid muscle
  • anterolateral part of the cricoid cartilage
  • inferior margin and inferior horn of the thyroid cartilage.
  • Superior laryngeal nerve
  • External laryngeal nerve
  • tilts/pulls prominence of thyroid cartilage anteriorly and inferiorly
  • elongates and tightens vocal ligaments
  • raises the pitch of voice
Thyro-arytenoid muscle
  • lower half of the posterior aspect of the thyroid cartilage and cricothyroid ligament
  • anterolateral arytenoid surface
  • Recurrent laryngeal nerve via inferior laryngeal nerve
  • pulls the arytenoid cartilages anteriorly
  • lowers the pitch of the voice
Lateral cricoarytenoid muscle
  • arch of cricoid cartilage
  • vocal process of arytenoid cartilage
  • pulls the muscular processes of arytenoid cartilages anteriorly and rotates them to adduct the vocal folds
Transverse arytenoid
muscle
  • ipsilateral arytenoid cartilage
  • contralateral arytenoid cartilage
  • pulls the arytenoid cartilages together causing adduction of vocal folds
  • reflexive sphincter
Oblique arytenoid
muscle
Posterior cricoarytenoid
muscle
  • posterior surface of the cricoid cartilage lamina
  • vocal process of arytenoid cartilage
  • rotates the vocal processes of the arytenoid cartilages laterally to abduct the vocal folds 
  • widens the rima glottidis
Vocalis muscle
  • lateral surface of the vocal process of the arytenoid cartilage
  • ipsilateral vocal ligament
  • tenses and relaxes the vocal ligaments and folds
Trachealis muscle
  • Spans posterior gaps in tracheal ring
  • para-sympathetic ganglia
  • allows expansion of the esophagus during swallowing

Transcript

Watch video only

The cervical viscera are composed of three layers named after their primary function.

The most superficial layer is the endocrine layer which contains the thyroid and parathyroid glands, then there’s the respiratory layer which contains the larynx and trachea and finally, the deepest layer is the alimentary layer which contains the pharynx and esophagus.

Focusing on the respiratory layer of the cervical viscera, this contains the larynx and trachea that routes air to the lungs, and gives everyone their own unique voice and saying that just made me aware of my own voice on this video recording!

So, let’s start with the larynx which is responsible for voice production and maintaining a patent airway.

The larynx is located in the anterior neck at the level of the bodies of the C3 to C6 vertebrae and connects the inferior part of the pharynx with the trachea. It also contains the vocal cords, or vocal folds, so it’s responsible for voice production.

Now, the larynx has a skeleton which is hardly a skeleton; rather, it’s formed of nine cartilages: thyroid, cricoid and epiglottic cartilages which are single and arytenoid, corniculate and cuneiform cartilages which come in pairs of two.

The thyroid cartilage is the largest cartilage and its superior border lies opposite the C4 vertebra.

It’s formed by two plate-like laminae which unite in the middle to form the laryngeal prominence also known as the Adam’s apple, which is well marked in males and less visible in females.

Superior to this prominence, the laminae diverge to form a V-shaped notch called the superior thyroid notch, and in the middle of the inferior border of the cartilage, a shallow indentation can be found called the inferior thyroid notch.

Elsevier

Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.

RELX