IRM - Basic Topography of the Upper Respiratory Tract (AP01)

upper respiratory tract innit

What are the functions of the nose?

• Respiration

• Olfaction

• Filtration of dust

• Humidification of inspired air

• Reception and elimination of secretions

• Warms inspired air

What is the basic shape of the nasal cavity?

Divided into two chambers (left and right) by the nasal septum, which is a medial wall.

What helps to slow the air down in the nasal cavity in order for it to get warmed and filtered?

Turbinates/conchae: Superior, middle and inferior conchae

What are the associated spaces underneath the conchae?

Superior, middle and inferior meatuses

What is the space at the top of the nasal cavity?

Spheno-ethmoidal recess

What is the opening at the front of the nasal cavity called?

Anterior nasal aperture

Where are the maxilla and nasal bones located?

Where are the perpendicular plate of ethmoid and vomer found?

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Where are the choanae located?

At the posterior nasal aperture.

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What are the divisions of the nasal cavity?

Where is the olfactory bulb/nerves, auditory tube and vestibule located in a cadaver?

What are the subdivisions of the pharynx? (from superior to inferior)

Nasopharynx, oropharynx and laryngopharynx

What is the location of the nasopharynx?

Posterior to nasal cavity

Superior to soft palate

What are the contents of the nasopharynx?

What is the function of the pharyngotymapnic tubes (eustachian tubes)?

• Connects the middle ear cavity to the nasopharynx.

• Responsible for equalising air pressure between atmosphere and middle ear.

• Tensor veli palatini muscles contract when swallowing or yawning, causing it to open and allow air to enter.

What is the location of the oropharynx?

Inferior to soft palate

Superior to base of tongue

Medial to palatoglossal and palatopharyngeal arches

Posterior to the oral cavity

What is Waldeyer’s ring?

The ring of lymphoid tissue in the pharynx.

What are the components of Waldeyer’s ring?

What are the functions of Waldeyer’s ring?

• Responsible for blocking and filtering air going through the ear, nose, etc.

• Part of the immune system

What is the location of the laryngopharynx?

Posterior to the larynx

From superior border of epiglottis to inferior border of cricoid cartilage

It narrows and becomes continuous with esophagus

How does air reach the airways in the laryngopharynx?

Via the laryngeal inlet

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What are the three constrictor muscles of the pharynx?

Superior, middle and inferior constrictors

Where are the pharyngeal tubercle and the pharyngeal raphe located?

What does the superior constrictor muscle attach to?

Superiorly: pharyngeal tubercle (occipital bone), base of skull via pharyngobasilar fascia

Posteriorly: pharyngeal raphe

Anteriorly: pterygoid hamulus, pterygomandibular raphe, mandible and side of tongue

What does the middle constrictor muscle attach to?

Posteriorly: pharyngeal raphe

Anteriorly: inferior end of stylohyoid ligament, greater and lesser horns of hyoid bone

What does the inferior constrictor muscle attach to?

Posteriorly: pharyngeal raphe

Encircles junction between pharynx and oesophagus

Anteriorly: oblique line of thyroid cartilage, cricoid cartilage

What is the motor innervation for constrictor muscles of the pharynx?

Innervation by the pharyngeal plexus, which is a combination of branches of mainly the vagus nerve (CN X) as well as the glossopharyngeal nerve (CN IX).

What are the longitudinal muscles of the pharynx?

Stylopharyngeus, salpingopharyngeus and palatopharyngeus

Where are the longitudinal muscles of the pharynx located?

How are the longitudinal muscles of the pharynx innervated?

Stylopharyngeus innervated by glossopharyngeal nerve (CN IX).

Salpingopharyngeus and palatopharyngeus are innervated by pharyngeal plexus, in particular the pharyngeal branch of the vagus nerve.

What is the stylopharyngeus associated with?

Runs from styloid process to thyroid cartilage

What is the salpingopharyngeus associated with?

Runs from the cartilage of pharyngotympanic tube and unites with palatopharyngeus

What is the palatopharyngeus associated with?

Runs from hard plate and palatine aponeurosis to the thyroid cartilage and oesophagus.

Where are nosebleeds likely to occur from?

Kiesselbach’s area, which contains anastomosing arteries.

What are the branches of the internal carotid artery?

Anterior and posterior ethmoidal arteries

What are the branches of the external carotid artery?

• Sphenopalatine artery

• Greater palatine artery

• Superior labial artery

• Maxillary artery

What are the sites of venous drainage from the nasal cavity?

Anteriorly to facial vein

Posteriorly to pterygoid venous plexus

Superiorly to cavernous sinus

What provides general sensation to the nasal cavity?

Trigeminal Nerve (CN V):

• Anterior and superior part of nasal cavity - sensation supplied by ophthalmic (V₁) division

• Posterior and inferior part of nasal cavity - sensation supplied by maxillary (V₂) division

What is the function of the sinuses in general at the nasal cavity?

To reduce the weightening of the skull

What are all the sinuses of the cavity lined with?

Mucosa

What are the three sinuses shown here?

Orange - frontal sinus

Green - ethmoidal sinus (air cells)

Blue - maxillary sinus

What does the spheno-ethmoidal recess do?

It drains posterior ethmoid cells and sphenoidal sinuses into superior meatus.

What does the middle meatus do?

It drains the middle ethmoidal cells, maxillary sinus and frontal sinus.

What does the inferior meatus do?

It drains the nasolacrimal duct, which drains tears from the ocular surface.

What bone(s) make up the floor of the nasal cavities?

Palatine process of the maxilla

What bone(s) make up the roof of the nasal cavities?

Ethmoid bone and sphenoid bone

What bone(s) make up the lateral and medial walls of the nasal cavities?

Medial - perpendicular plate of ethmoid, vomer

Lateral - lacrimal bone and frontal process of maxilla

What is the significance of the paranasal sinuses in relation to the respiratory system?

They are lined with mucosal cells which produce and secrete mucus.

They also drain air into the nasal cavities.

Why must microorganisms and particulates be removed from the inspired air and how is this achieved?

What fluid can leave the nose after trauma to the roof of the nasal cavity?

Cerebrospinal fluid (CSF)

What clinical signs might you find with a base of skull fracture?

• Infections

• Seizures

• Bleeding around the brain

What are some initial treatments that can reduce bleeding?

Pinching the nose

What leads to sinusitis?

Infection of the paranasal sinus epithelium and a subsequent build-up of infected material.

Which sinus is particularly susceptible to sinusitis and why?

Maxillary sinus as it is the only sinus that is located inferior to the nose.

What imaging technique has been used here?

X-ray

What imaging technique has been used here?

CT scan

What specific tonsillar tissues are located in the nasopharynx?

Adenoid tonsils and tubal tonsils.

What is an adenoidectomy? When might it be performed?

Surgical removal of adenoid tonsils.

Performed in cases of recurring sinusitis.