Pharynx and Larynx

Question 1

What are the borders of the pharynx?

Answer 1

From the cranial base to the lower border of the cricoid cartilage (where it becomes continuous with the oesophagus)

Question 2

What are the 3 main sections of the pharynx?

Answer 2

Nasopharynx
Oropharynx
Layngopharynx

Question 3

Explain the borders of the nasopharyx

Answer 3

It is the area above the soft palate and behind the nose.
The floor is formed by the soft palate and the posterior wall is formed by the superior constrictor muscle.
On the lateral wall is the opening to the auditory tube and also see lymphoid tissue.

Question 4

Explain the borders of the oropharynx

Answer 4

The area inferior to the soft palate and communicates anteriorly with the oral cavity.

Raising the soft palate separates it from the nasopharynx.

Its anterior border is made of the palatgoglossal and palatopharygeal arches.
Palatine tonsils sitting between the arches.

Question 5

What are the 4 layers to the pharynx walls?

Answer 5

• Mucosa
• Submucosa
• Muscular
• Buccopharyngeal folds

Question 6

What 3 pharynx muscles contract during swallowing?

Answer 6

Superior constrictor
Middle constrictor
Inferior constrictor

Question 7

What nerves supply the constrictor muscles?

Answer 7

Nerve supply is mostly through the pharyngeal arch of the vagus nerve.

(inferior constrictor also supplied by the recurrent branch of the pharynx)

Question 8

What are the origins and insertions of each of the constrictor muscles?

Answer 8

Superior = from the raphe between the mandible and pterygoid palate TO the pharyngeal tubercle of the occipital bone.

Middle = from the stylohoid ligament and horns of the hyoid to the pharyngeal raphe

Inferior = from the oblique line of thyroid and cricoid to the junction between the pharynx and oesophagus

Question 9

What are the 2 important longitudinal muscles found in the pharynx?

Answer 9

1) Palatopharyngeus muscle = arises from the palatal aponeurosis and inserts into the posterolateral part of the pharynx
2) Stylopharyngeus muscle = from styloid process to the pharynx

Question 10

Do the pharynx go up or down during swallowing?

Answer 10

They go up

Question 11

What nerves supply the pharynx?

Answer 11

Motor = all muscles except the stylophayngeus are supplied by the pharyngeal branches of the vagus nerve.
The stylopharyngeus is supplied by the glossopharyngeal nerve.

Sensory = the glossophayngeal nerve is the main sensory supply to the pharynx.
The maxillary division of the trigeminal supplies the soft palate and the root of the pharynx.
The vagus supplies the area around the pharyngeal inlet

Question 12

What arteries and veins supply the pharynx?

What nodes drain the lymph?

Answer 12

Arteries:
- Ascending phayrngeal, superior and inferior thyroid, facial and maxillary arteries

Veins:
- A plexus on the pharynx that communicate with the pterygoid plexus

Deep cervical lymph nodes

Question 13

What is the larynx responsible for?

Answer 13

Voice production

Air passageway linking the pharynx with the trachea.

Sphincter to prevent food entering the trachea.

Question 14

Where is the larynx found and how many different cartilages does it have?

Answer 14

The larynx extends from the base of the tongue (C3) to the trachea (C6). The inlet lies immediately behind the posterior third of the tongue.

Three large cartilages: thyroid, cricoid and epiglottis (unpaired)

Three small paired cartilages: the arytenoid, cuneiform and corniculate

Question 15

Explain the 3 unpaired cartilages of the larynx (thyroid, cricoid and epiglottis)

Answer 15

Thyroid = the largest and consists of two plates joined anteriorly in the midline.

Cricoid = sits immediately below the thyroid cartilage at the level of C6 and is shaped like a signet ring.
It completely encircles the larynx.

Epiglottis = a firoboelastic cartilage shaped like a leaf. Has a stem anchored into the angle of the thyroid laminae.
The broad leaf is orientated upwards and backwards lying behind the hyoid bone and reaching the posterior part of the tongue.

Question 16

Explain the 3 paired cartilages

arytenoid, corniculate, cuneiform

Answer 16

Arytenoid : These two pyramid -shaped cartilages lie on the posterior lamina of the cricoid cartilage and articulate via a synovial joint. They provide attachment for the vocal process as well as several muscles involving in tensing the vocal processes.

Corniculate: these tiny elastic cartilages sit at the top of the apices of the arytenoid cartilages to extend the cartilage length

Cuneiform: these are found in the aryepiglottic folds (from the arytenoid cartilages to the epiglottis)

Question 17

What are the 2 categories of muscles in the larynx?

Answer 17

intrinsic and extrinsic muscles

Extrinsic muscles of the larynx: they have a remote origin but insert into the larynx or hyoid bone. These supra and infra hyoid muscles acts to move the larynx up and down

Intrinsic muscles of the larynx: have both their origin and insertion in the laryngeal cartilages

Question 18

What are the 3 roles of the intrinsic muscles of the larynx?

Answer 18

Open the rima glottidis to allow the passage of air in and out

Close the vestibule and rima during swallowing to prevent aspiration of food

Control of the tension of the vocal folds for phonation

Question 19

What nerves supply the larynx?

Answer 19

Mainly the superior laryngeal nerve (supplies the upper areas such as the epiglottis and the cricoid) where as the recurrent laryngeal nerve provides the lower part of the larynx.

Question 20

What is the blood supply to the larynx?

Answer 20

Mainly the superior and inferior thyroid artery. These then go out into other branches to supply blood to the larynx.

Superior thyroid artery branches from the external carotid.

Inferior thyroid artery branches out from the subclavian artery.

2 superior and 2 inferior thyroid arteries.

Laryngeal veins drain out onto the superior and inferior thyroid veins.

Question 21

When does phonation normally take place?

How does phonation work?

Answer 21

Normally takes place during expiration.

Pressure then builds up from below until it forces the folds apart allowing the air to escape, the cycle is repeat and converts the air into a series of puffs at a frequency determined by the sub-glottal pressure and the mass and tension on the vocal ligaments. The frequency of the oscillating air also determines the pitch which varies to allow intonation and expression