Nasal cavity to larynx

Question 1

What are functions of nose and nasal cavity?

Answer 1

Form a box of bone and cartilage that hold the cavity open against inspiratory pressure. Functions to warm, humidify and filter inhaled air, sense of smell - olfaction

Question 2

What do lateral walls possess and what is it’s function?

Describe mucous membrane

Answer 2

Have conchae (turbinates) and meati 
Airway that creates turbulence to assist functions

The mucous membrane is highly vascular and lined with respiratory epithelium i.e. pseudo-stratified ciliated columnar interspersed with goblet cells that secrete mucus

Question 3

What are bones of lateral wall and roof of nasal cavity?

Answer 3

Roof - nasal, frontal, ethmoid, sphenoid bones

Lateral wall - nasal, maxilla, lacrimal, ethmoid, palatine, medial pterygoid plate of sphenoid

Question 4

What is in midline septum, medial wall? Where does air pass through in it?

Answer 4

3 skeletal elements - vomer, septal cartilage, perpendicular plate of ethmoid

Air passes through the posterior choanae (vomer, medial pterygoid plate of spehnoid) into the nasopharynx

Question 5

Where does paranasal sinus enter nasal cavity and where do tears drain?

Answer 5

Paranasal air sinuses enter the middle meatus, inferior/lateral to the middle concha

The nasolacrimal duct drains tears from conjuctival sac of eye to the inferior meatus

Question 6

a) Which structures are excavated into air spaces in early childhood to adolescence
b) Which structures extend into sinuses?

Answer 6

a) Frontal, sphenoid, ethmoid, maxilla

b) Nasal mucous membrane, respiratory epithelium

Question 7

How may clearance of mucous from maxillary sinus be compromised?

Answer 7

Clearance dependent on cilary action which may be compromised by infection, possibly leading to sinusitis. A deviated septum may also predispose to sinusitis.

Question 8

Discuss nerve supply

Answer 8

The Trigeminal nerve – Cranial V is sensory and has ophthalmic (running in the adjacent orbit) and maxillary divisions
The Facial nerve – Cranial VII - somatic motor but also carries parasymp fibres that jump onto and then hitchhike ophthalmic (v1) and maxillary (V2) branches of trigeminal

Therefore divisions of trigeminal are distributing both sensory and parasymp (secretomotor) fibres

Question 9

Where is site of emergency access to airway?

Answer 9

Median cricothyroid ligament

Question 10

What/where is cricoid?

Answer 10

Signet ring with the lamina posteriorly

Articulates with the arytenoids and the thyroid

Question 11

Arytenoid - describe shape and location

Answer 11

Pyramidal shape, 3 sides and a base which articulates with the sloping shoulders of the cricoid lamina
Topped by the corniculate and cuneiform cartilages
Vocal process anteriorly for attachment of vocal ligament or fold

Question 12

What are the two intrinsic membranes or ligaments?

Answer 12

Quadrangular from arytenoid to thyroid and epiglottis
Cricoval (or cricothyroid) from cricoid and arytenoid to the thyroid - forms the conus elasticus

It’s anterior thickeneing - the median cricothyroid ligament is the site of emergency access of airway

Question 13

What is the function of the vocal folds?

Answer 13

Control laryngeal diameter for speech, coughing, sneezing and raising the intra-abdominal pressure, which is vital in parturition, micturition, defecation and lifting heavy objects

Muscles within and adjacent to the vocal folds narrow or widen the opening between them (rima glottis or glottidis), or alter their tension

Question 14

Consider muscles that:

• Open/close inlet
• Open/close rima glottidis (and rima vestibuli)
• Lengthen/shorten the vocal folds - rocking at cricothyroid joints

Answer 14

• Open/close inlet - aryepiglottic folds
• Open/close rima glottidis - arytenoid gliding and rotation
• Lengthen/shorten the vocal folds - rocking at cricothroid joints