Pharynx and Larynx Flashcards
What are the borders of the pharynx?
From the cranial base to the lower border of the cricoid cartilage (where it becomes continuous with the oesophagus)
What are the 3 main sections of the pharynx?
Nasopharynx
Oropharynx
Layngopharynx
Explain the borders of the nasopharyx
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.
Explain the borders of the oropharynx
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.
What are the 4 layers to the pharynx walls?
- Mucosa
- Submucosa
- Muscular
- Buccopharyngeal folds
What 3 pharynx muscles contract during swallowing?
Superior constrictor
Middle constrictor
Inferior constrictor
What nerves supply the constrictor muscles?
Nerve supply is mostly through the pharyngeal arch of the vagus nerve.
(inferior constrictor also supplied by the recurrent branch of the pharynx)
What are the origins and insertions of each of the constrictor muscles?
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
What are the 2 important longitudinal muscles found in the pharynx?
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
Do the pharynx go up or down during swallowing?
They go up
What nerves supply the pharynx?
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
What arteries and veins supply the pharynx?
What nodes drain the lymph?
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
What is the larynx responsible for?
Voice production
Air passageway linking the pharynx with the trachea.
Sphincter to prevent food entering the trachea.
Where is the larynx found and how many different cartilages does it have?
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
Explain the 3 unpaired cartilages of the larynx (thyroid, cricoid and epiglottis)
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.
Explain the 3 paired cartilages
arytenoid, corniculate, cuneiform
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)
What are the 2 categories of muscles in the larynx?
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
What are the 3 roles of the intrinsic muscles of the larynx?
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
What nerves supply the larynx?
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.
What is the blood supply to the larynx?
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.
When does phonation normally take place?
How does phonation work?
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
