Nose, nasopharynx & larynx

What forms the nasal cavity?

> Nasal cartilage & bone

> Cribriform plate of ethmoid

> Hard palate

> Sphenoid

> Alar cartilages

What forms the nasal septum?

> Septal cartilage

> Vertical plate of ethmoid

> Vomer

Four major functions of nasal cavity?

> Humidify and warm inhaled air

> Trap particles from inhaled air

> Olfaction

> Drainage of lacrimal ducts & paranasal sinuses

Where are the conchae?

Lateral walls of nasal cavity

Conchae are also known as...

Turbinate bones

What bones do the nasal conchae come from?

Superior & middle: ethmoid

Inferior: its own bone

Function of conchae?

Increase surface area & create tunnels to slow down air for humidification and warming

Where does the sphenoid sinus drain?

Sphenoethmoidal recess, superiorly to the superior concha

What drains into the superior meatus?

Posterior ethmoidal sinus

What drains into the middle meatus?

Frontal, maxillary & anterior ethmoidal sinuses

What drains into the inferior meatus?

Nasolacrimal duct & Eustachian tube (though latter is a bit posterior)

General sensation of the nasal cavity?

Ophthalmic and maxillary - trigeminal V

Nasal mucous and lacrimal glands are supplied by...?

Parasympathetic branches of facial nerve. Pterygopalatine ganglion.

Where might sinusitis arise from?

> Extension of *upper respiratory tract infection*

> *Blockage* of sinus drainage eg. allergic inlammation

> *Maxillary posterior teeth*, which extend into maxillary sinus

How might sinusitis present?

Toothache, as maxillary nerve innervates both maxillary teeth and sinus

Where is arterial supply of the nasal mucosa from?

Internal carotid: ethmoidal branches from ophthalmic

External carotid: sphenopalatine and greater palatine from facial

What is different about the anterior part of the nose wrt arterial supply?

Particularly well developed anastomoses (Little's area).

Common site for nosebleeds (90%) particularly in younger people.

Another name for nosebleeds?

Epistaxis

Spinal level of larynx?

C3-6

What cartilage forms the Adam's apple?

Thyroid

Where is the cricoid cartilage found?

Below the thyroid cartilage, at the top of the trachea

Shape of the crichoid cartilage?

Complete ring, larger at back. 'Signet ring'.

Where are the arytenoid cartilages found?

On top of the crichoid, in the posterior wall of the larynx.

Where is the epiglottis found?

At the top of the larynx

What cartilage is found at the apices of the arytenoid cartilages?

Corniculate cartilages

What shape are the arytenoid cartilages?

Pyramid-shaped

What cartilage is found at the laryngeal entrance?

Cuneiform - strengthens aryepiglottic folds

Name the cartilages of the larynx.

> Epiglottis

> Thyroid cartilage

> Cricoid cartilage

> Arytenoid cartilages

> Corniculate cartilages

> Cuneiform cartilages

Three major regions of the larynx?

Supraglottis (vestibule)

Glottis

Subglottis

Describe the supraglottis?

From inferior surface of epiglottis to vestibular folds

The false vocal cords is another name for...?

Vestibular folds

What is the role of the vestibular folds?

They are fixed, and protect the larynx & underlying vocal folds

Describe the glottis?

Middle region of larynx containing vocal folds

Describe the subglottis?

From the base of the glottis to the inferior border of the cricoid cartilage

What forms the vocal folds?

Vocal ligaments and vocalis muscle

What must happen for the vocal folds to make noise when air is forced across them?

Free margins must b closely apposed

Where do the vocal ligaments run between?

Anteriorly: junction of thyroid cartilage lamellae

Posteriorly: vocal processes of arytenoid cartilages

What is the aperture of the vocal folds known as?

Rima glottis

Innervation of intrinsic laryngeal muscles?

All recurrent laryngeal except cricothyroid, which is external laryngeal (branch of superior laryngeal)

Major function of cricothyroid muscle?

Pitch control

Function of extrinsic laryngeal muscles?

Move larynx as a whole (superiorly/inferiorly) during swallowing

Sensory innervation of larynx?

Internal laryngeal (branch of superior laryngeal)

VOCAL FOLDS

Recurrent laryngeal

What is an abnormal connection between the lumens of oesophagus & trachea known as?

Tracheoesophageal fistula

What is congenital tracheoesophageal fistula caused by?

Abnormal formation of tracheoesophageal septum, separating developing trachea from foregut.

What is congenital tracheoesophageal fistula associated with?

Other congenital malformations particularly cardiac defects.

Congenital abnormality where oesophagus is blind-ending?

Oesophageal atresia

How might oesophageal atresia be detected antenatally?

> Polyhydramnios

> Absence of fetal stomach bubble

Symptoms of oesophageal atresia?

Breathing difficulties, choking, eeding difficulties

How might the larynx be affected in cardiothoracic surgery?

Left recurrent laryngeal nerve may be damaged as it loops around the ligamentum arteriosum.

Ipsilateral paresis, voice hoarseness.

How can you improve voice damage caused by nerve damage?

Damage is usually permanent, but voice weakness can be improved by surgical medialisation of vocal cords to improve their apposition.

What are the aryepiglottic folds?

Triangular folds of mucous membrane in the supraglottal larynx extending from epiglottal borders to arytenoids

Where are the piriform fossae?

Posterolaterally to either side of laryngeal opening

What joins the hyoid and the thyroid cartilage?

Thyrohyoid membrane

Cricovocal membrane is another word for...

Cricothyroid ligament

Function of intrinsic muscles of larynx

> Cricothyroid: pitch control

> Posterior cricoarytenoids: abduct (open) glottis

All other adduct (close) glottis.

What are the strap muscles of the neck?

Infrahyoid muscles, found anteriorly in neck

Innervation of infrahyoid muscles?

C1-3

Sites of incision for laryngotomy vs tracheostomy?

Laryngotomy - cricothyroid membrane

Tracheostomy - trachea, between 2nd and 3rd cartilage rings