Anatomy of the head and neck 1

Question 1

What is the function of the internal nasal septum?

Answer 1

The internal nasal septum separates the nasal cavity into two nostrils

Question 2

What are the bones of the nasal septum divided into?

Answer 2

The bones that contribute to the nasal septum can be divided into:

Paired bones: Nasal, maxillary and palatine bones

Unpaired bones: Ethmoid and vomer bones.

Question 3

What forms the anterior and posterior parts of the nasal cavity

Answer 3

The anterior and posterior parts are formed by the septal cartilage and vomer bone respectively.

Question 4

What separates the oral cavity from the nasal cavity?

Answer 4

The floor of the nasal cavity is formed by the hard palate, separating izt from the oral cavity.

Question 5

What does the hard palate consist of?

What forms the roof of the nasal cavity?

Answer 5

The hard palate consists of the palatine bone posteriorly, and the palatine process of the maxilla anteriorly. The cribriform plate of the ethmoid bone forms the roof of the nasal cavity.

Question 6

What are the 4 functions of the nasal cavity

Answer 6

• Warms and humidifies the inspired air.
• Removes and traps pathogens and particulate matter from the inspired air.
• Responsible for sense of smell.
• Drains and clears the paranasal sinuses and lacrimal ducts.

Question 7

Label the internal nasal cavity

Answer 7

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Question 8

What are the 3 divisions of the nasal cavity?

Answer 8

• Vestibule – the area surrounding the anterior external opening to the nasal cavity.
• Respiratory region – lined by a ciliated psudeostratified epithelium, interspersed with mucus-secreting goblet cells.
• Olfactory region – located at the apex of the nasal cavity. It is lined by olfactory cells with olfactory receptors.

Question 9

What bones project outside the walls of the nasal cavity?

Answer 9

Projecting out of the lateral walls of the nasal cavity are curved shelves of bone. They are called conchae (or turbinates). The are three conchae – inferior, middle and superior.

Question 10

What do the conchae create?

Answer 10

They project into the nasal cavity, creating four pathways for the air to flow. These pathways are called meatuses:
• Inferior meatus – between the inferior concha and floor of the nasal cavity.
• Middle meatus – between the inferior and middle concha.
• Superior meatus – between the middle and superior concha.
• Spheno-ethmoidal recess – superiorly and posteriorly to the superior concha.

Question 11

What is the function of the conchae?

Answer 11

The function of the conchae is to increase the surface area of the nasal cavity – this increases the amount of inspired air that can come into contact with the cavity walls. They also disrupt the fast, laminar flow of the air, making it slow and turbulent. The air spends longer in the nasal cavity, so that it can be humidified.

Question 12

Label the nasal cavity

Answer 12

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Question 13

Label the nasal turbinate’s

Answer 13

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Question 14

What are the paranasal sinuses, how many are they and what are they called?

Answer 14

The paranasal sinuses are air-filled extensions of the nasal cavity. There are four paired sinuses – named according to the bone in which they are located – maxillary, frontal, sphenoid and ethmoid. Each sinus is lined by a ciliated pseudostratified epithelium, interspersed with mucus-secreting goblet cells.

Question 15

What is the function of the paranasal sinuses?

Answer 15

The function of the paranasal sinuses is a topic of much debate. Various roles have been suggested:
• Lightening the weight of the head
• Supporting immune defence of the nasal cavity
• Humidifying inspired air
• Increasing resonance of the voice

Question 16

Label the paranasal sinuses

Answer 16

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Question 17

Label the frontal skull

Answer 17

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Question 18

What do the Maxillary, frontal and anterior ethmoidal sinuses drain into?

Answer 18

• Maxillary, frontal and anterior ethmoidal sinuses all drain through canals (called infundibula- plural) into the middle meatus (space between turbinates), specifically in the semilunar hiatus (groove) through openings called ostia (ostium- singular).

Question 19

What does the middle, posterior and sphenoidal air cells drain into?

Answer 19

• The middle ethmoidal air cells drain into the ethmoidal bulla (prominence) of the middle meatus.
• The posterior ethmoidal air cells drain into the superior meatus.
• The sphenoidal sinuses drain into the spheno-ethmoidal recess, superior to the superior concha.
• It is worth mentioning that the nasolacrimal duct opens in the inferior meatus of the nasal cavity and this is the reason why the nose starts to run when a person is crying.

Question 20

What is the arterial supply to the 4 sinuses?

Answer 20

• Maxillary sinuses– branches of the maxillary artery
• Frontal sinuses- branches of the ophthalmic artery
• Ethmoidal sinuses- branches of the ophthalmic artery
• Sphenoidal sinuses- branches of the ophthalmic artery

Question 21

What is the maxillary sinus innervated by?

Answer 21

Alveolar branches of the maxillary division (V2) of the trigeminal nerve (CN V)

Question 22

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Answer 22

• A SMALL PART OF FOREIGN PARTICLES ARE TRAPPED IN THE MUCUS OF THE SINUSES (to avoid them going into our airway) AND EXPELLED FROM THE NASAL CAVITY
• HOWEVER, THE MAXILLARY SINUSES ARE THE ONLY SINUSES THAT DRAIN SUPERIORLY INTO THE NASAL CAVITY VIA A VERTICAL/DIAGONAL CANAL
• THEREFORE OBSTRUCTION OF THESE SINUSES IS QUITE FREQUENT AND MUCUS+FOREIGN PARTICLES REMAINED TRAPPED IN THE SINUSES CAUSING INFECTIONS

Question 23

Label the sinuses mucosa flow

Answer 23

• The red arrows indicate the direction of mucociliary flow; the blue area is the middle meatus; and the green stars are the infundibulum (passage/canal from sinuses to nasal cavity).
• Now the infundibulum is easily obstructed not only because of its position and orientation (being a vertical canal located at the top of the sinuses does not favour the exit of the mucus) but also because during sinus infections the mucosal layer gets swollen and inflamed and block this passage, thus causing the mucus and particles to be trapped inside the sinuses

Question 24

What is Endoscopic Maxillary Sinus surgery?

Answer 24

Functional Endoscopic sinus surgery is based on the removal of uncinate process to expose the infundibulum and enlarge the passage between the nasal cavity and the maxillary sinuses.

Question 25

Label the anatomy of the ethmoid bone

Answer 25

• Crista galli is a crest, below this are foramen for the factory of the olfactory nerves from the olfactory bulb
• Within the ethmoidal cavities are air cells covered in mucus ciliated membrane

Question 26

What is the pharynx and what does it connect?

Answer 26

The pharynx is a muscular tube that connects the oral and nasal cavity to the larynx and oesophagus.

Question 27

Where does the pharynx begin and what is it made off?

Answer 27

It begins at the base of the skull and ends at the inferior border of the cricoid cartilage (C6). The pharynx is comprised of three parts (superior to inferior):
• Nasopharynx
• Oropharynx
• Laryngopharynx

Question 28

Where is the nasopharynx found?

Answer 28

The nasopharynx is found between the base of the skull and the soft palate. It is continuous with the nasal cavity and performs a respiratory function by conditioning inspired air and propagating it into the larynx.

Question 29

What does the nasopharynx contain?

Answer 29

This part of the pharynx is lined with respiratory epithelium; ciliated pseudostratified columnar epithelium with goblet cells.

The posterosuperior nasopharynx contains the adenoid tonsils, which enlarge between 3-8 years of age and then regress.

It contains the auditory tube, a cartilagous structure that connects the nasopharynx to the ear.

The pharyngeal tonsils are also present

Question 30

Where is the oropharynx located?

What does it contain?

Answer 30

The oropharynx is the middle part of the pharynx, located between the soft palate and the superior border of the epiglottis.

• Posterior one-third of the tongue.
• Lingual tonsils – lymphoid tissue at the base of the tongue.
• Palatine tonsils – lymphoid tissue located in the tonsillar fossa (between the palatoglossal and palatopharyngeal arches of the oral cavity).

Question 31

What is Waldeyer’s ring?

Answer 31

Waldeyer’s ring is the ring of lymphoid tissue in the naso- and oropharynx formed by the paired palatine tonsils, the adenoid tonsils and lingual tonsil.

Question 32

What is the most distal part of the pharynx?

Where is it found and what does it contain?

Answer 32

• The most distal part of the pharynx, the laryngopharynx is located between the superior border of the epiglottis and inferior border of the cricoid cartilage (C6). It is continuous inferiorly with the oesophagus.
• It is found posterior to the larynx and communicates with it via the laryngeal inlet, lateral to which one can find the piriform fossae.
• The laryngopharynx contains the middle and inferior pharyngeal constrictors.

Question 33

What are the 3 divisions of the pharynx and what do they contain?

Answer 33

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Question 34

Where does the nasopharynx, oropharynx and laryngopharynx run from?

Answer 34

The nasopharynx is found between the nasal choanae (back of nasal cavity) and the soft palate (and C1/C2). It is continuous with the nasal cavity, and performs a respiratory function by conditioning inspired air and propagating it into the larynx. This part of the pharynx is lined with respiratory epithelium.

The oropharynx is the middle part of the pharynx, located between the soft palate and the superior border of the epiglottis. It contains the posterior 1/3 of the tongue, the lingual tonsils and the palatine tonsils as well as the superior constrictor muscle. The oropharynx is involved in the voluntary and involuntary phases of swallowing.

The most distal part of the pharynx, the laryngopharynx is located between the superior border of the epiglottis and inferior border of the cricoid cartilage (C6). It is continuous inferiorly with the oesophagus. The laryngopharynx contains the middle and inferior pharyngeal constrictors.

Question 35

What are the 2 muscle groups of the pharyx?

Answer 35

There are two main groups of pharyngeal muscles: longitudinal and circular or constrictor muscles.

Question 36

What are the 3 constrictor muscles and where do they run from?

Answer 36

The constrictor muscles are three (sup, middle, inferior constrictor) and span from the nasopharynx down to the oesophagus.

They act to constrict the pharynx to deliver a bolus of food into the oesophagus.

Question 37

What are the 3 longitudinal muscles?

What is there function?

Answer 37

The longitudinal muscles are three:
• Stylopharyngeus
• Palatopharyngeus
• Salpingopharyngeus

They act to shorten and widen the pharynx and elevate the larynx during swallowing/deglutition

Note: in addition to contributing to swallowing, the salpingopharyngeus also opens the Eustachian tube to equalise the pressure in the middle ear.

Question 38

What are the muscles of the pharynx innervated by?

Answer 38

The muscles of the pharynx are mostly innervated by the vagus nerve – the only exception being the stylopharyngeus muscle, innervated by the glossopharyngeal nerve.