Airway

Question 1

Describe the basic structure of the upper airways?

Answer 1

Upper airway comprises of all structures from the nasal cavity to the end of the larynx. Some key structures include the nasal cavity, the pharyn, and the larynx.

Question 2

What are the 3 broad divisions of the pharynx?

Answer 2

NasoPharynx, OroPharynx, Laryngopharynx

Question 3

What anatomical landmarks demarcate the the start and end of the Pharynx?

Answer 3

From the nose (above C1) to C6

Question 4

What anatomical landmarks demarcate the start and end of the upper airways?

Answer 4

Nose to the sternal notch

Question 5

Broadly what is structure of the pharynx?

Answer 5

The pharynx can be broken down into the layers, the musculature, the vasculature and the nerve supply

Question 6

What is the mucsoa of the pharynx?

Answer 6

Mucosa - squamous and columnar epithelium

Question 7

What are the muscles of the pharynx?

Answer 7

Muscles - Superior, middle and inferior pharyngeal constrictors

Question 8

What vessels supply the pharynx?

Answer 8

Fed by the external carotid artery by specific vessels including the superior laryngeal, lingual, ascending palatine, tonsillar, greater palatine

Question 9

What are the cranial nerves

Answer 9

1 - Olfactory
2 - Optic nerve
3 - Occularmoter
4 - Trochlear
5 - Trigeminal
6 - Abducens
7 - Facial
8 - Vestibulocochlear
9 - Glossopharyngeal
10 - Vagus 
11- Accessory
12 - Hypoglossal

Question 10

Nerve supply of pharynx

Answer 10

All arise from the pharyngeal plexus (cranial nerve 9 and 10)

Question 11

Nerve supply of the larynx

Answer 11

Recurrent laryngeal nerve primarily

Question 12

Broadly describe the structure of the larynx

Answer 12

Extends from the hyoid bone to the sternal notch and encompasses the thyroid structures and the epiglottis/ glottis

Question 13

Vertebral levels of the larynx

Answer 13

From C3 (hyoid bone) and extends to T2/3 (sternal notch)

Question 14

What cartilages make up the larynx

Answer 14

Thyroid cartilage - is shield shaped, with two laminae the meet at the midline enveloping the thyroid notch
Cricoid cartilage - signet ring shaped
Arytenoid cartilage - pyramid shaped
Epiglottis - leaf shaped structure attached anteriorly to the thyroid cartilage and the base of the tongue

Question 15

Ligaments of the larynx

Answer 15

Extrinsic including the thyrohyoid, cricotracheal, cricothyroid and hypoepiglottic

Question 16

Muscles of the larynx and briefly function

Answer 16

Extrinsic group - Sternothyroid, Thyrohoid and inferior constrictor (from the pharynx)
Intrinsic - (responsible for cord opening) Post. Cricoarytenoid (true abductors), Lat. cricoarytenoid, transverse arytenoids (close the cords), Aryepiglottic (close laryngeal outlet when swallowing), Thyroepiglottic (assist in sphincter closure at laryngeal inlet) Cricothyroid muscles (stretches the vocal cords) Thyroarytenoids (draws the arytenoid in and relaxes the cords) Vocalis (adjusts the cord tension)

Question 17

Key differences in paediatric and adult patients in upper airway anatomy

Answer 17

• Larynx is positioned higher
• Shortened neck
• Tongue is larger relative to the mouth
• Head and occiput are relatively larger compressing the front the neck when supine
• Narrowest point is the cricoid ring
• Stiffer and larger epiglottis