Organs - Larynx overview

Question 1

Where is located?

Functions?

Answer 1

Anterior neck - it is a component of the respiratory tract.

Between C3-C6.

Phonation, cough reflex and protection of the lower respiratory tract.

Question 2

Anatomical relations?

Clinical relevance?

Answer 2

Anteriorly - infrahyoids

Laterally - lobes of thyroid glands

Posteriorly - oesophagus

Clinical relevance - pressure can be placed on the cricoid cartilage during intubation to prevent regurgitation of gastric contents.

Question 3

Anatomical structure of the larynx?

Epithelium?

Answer 3

Can be divided into three sections:

1) Supraglottis - inferior surface of epiglottis to the false vocal cords (vestibular folds)
2) Glottis - contains vocal cords - opening of vocal cords is known as rima glottidis - size is altered by muscles
3) Subglottis - inferior border of glottis to the cricoid cartilage

Pseudostatified ciliated columnar epithelium - note that the true vocal cords are line with stratified squamous epithelium.

Question 4

Vasculature

Answer 4

1) Superior laryngeal artery - branch of the superior thyroid (derived from the ECA)
2) Inferior laryngeal artery - branch of the inferior thyroid (derived from the thyrocervical trunk) - follows the recurrent laryngeal nerve into the larynx

Venous drainage by superior and inferior laryngeal veins.

Superior laryngeal drains into the IJV via superior thyroid.

Inferior laryngeal drains into the left brachiocephalic via inferior thyroid.

Question 5

Innervation?

Answer 5

Motor and sensory innervation by branches of the vagus nerve.

1) Recurrent laryngeal nerve
- sensory innervation to the subglottis
- motor innervation to the internal muscles (except cricothyroid)
2) Superior laryngeal nerve
- internal branch - sensory innervation to the supraglottis
- external branch - motor innervation to the cricothyroid

Question 6

Clinical relevance - vocal cord paralysis

Answer 6

Vocal cords are responsible for production of speech.

Movement is controlled by intrinsic muscles - majority is innervated by the recurrent laryngeal nerve, except cricothyroid.

RLN palsy causes:

• Apical lung tumour
• Thyroid cancer
• Aortic aneurysm
• Cervical lymphadenopathy
• Iatrogenic

Unilateral RLN palsy - other vocal cord compensates - speech not much affected.

Bilateral RLN palsy - rima glottidis closes - breathing impaired, phonation reduced - medical emergency.