Session 11 - Pharynx and Larynx Flashcards
From where to where does the pharynx extend to, anteriorly and posteriorly?
From cranial base to inferior border of cricoid cartilage anteriorly
And Inferior border of C6 posteriorly.
What 3 parts is the pharynx divided into?
- Nasopharynx
- Oropharynx
- Laryngopharynx/hypopharynx
What type of epithelium does each part of the pharynx have?
Nasopharynx - pseudostratified ciliated with goblet cells
Oropharynx - Stratified squamous non keratinised
Laryngopharynx - Stratified sqmaous non keratinised
From where to where does the nasopharynx extend?
top of pharynx to bottom of soft palate/uvula.
Why might an infection lead to blockage of the eustachian tube? What disease does this lead to?
Lymphoid tissue forms a Tonsillar ring around the superior part of the pharynx, which aggregates to form the Adenoids. The adenoids may become swollen during infection in children
Leads to otitis media
From where to where does the oropharynx extend?
Soft palate to superior border of epiglottis
From where to where does the laryngopharynx extend?
superior border of epiglottis to inferior border of cricoid cartilage
what are the two muscular layers of the pharynx?
outer circular muscle layer and inner longitudinal mucle layer.
What is the function and action of the outer circular muscle layer of the pharynx?
During swallowing the muscle constrict to propel the bolus of food downwards. Muscles overlap each other to achieve this.
What are the 3 muscles of the inner longitudinal muscle layer? What is their function?
- Stylopharyngeus
- Palatopharyngeus
- Salpingopharyngeus
Act to shorten and widen pharynx
How is the pharynx innervated? and how is this plexus formed?
Pharyngeal plexus - formed from vagus, glossopharyngeal, and sympathetic fibres from superior cervical ganglion
What is the motor innervation of the pharynx?
Vagus nerve
Except stylopharyngeus muscle which is glossopharyngeal nerve
Describe the voluntary and pharyngeal phase of swallowing
Voluntary Phase
- Tongue moves the bolus back onto the pharynx
Pharyngeal Phase
Pressure receptor in palate triggers:
- Inhibition of breathing
- Raising of the larynx – Suprahyoid and Longitudinal Muscles
- Closure of the glottis
- Opening of the upper oesophageal ‘sphincter’
What are the arteries that supply the pharynx? Which artery do they originate from?
From external carotid:
- Ascending pharyngeal
- lingual
- facial
- maxillary
What is the venous drainage of the pharynx?
Pharyngeal venous plexus –> internal jugular vein
What clinical features can occur in enlarged adenoids?
- Nasal obstruction
- Mouth breathing, nasal speech
- Feeding difficulty (especially infants)
- Snoring / Obstructive Sleep Apnoea
- Block the opening of the Eustachian Tube
During what ages is the maximal size for adenoids?
3-8 then regression
Where does the palatine tonsils lie?
lies between palatoglossal arch and palatopharyngeal arch
What is the lymphatic drainage of the palatine tonsils?
Jugulo-digastric (tonsillar) node
What is quinsy? How is it treated?
Peritonsillar abscess pushing uvula to other side
Requires drainage
Name the 3 regions food is likely to become stuck in the oropharynx
- Vallecula - pouch between tongue and epiglottis
- Base of tongue
- Region of palatine tonsil
Name the 2 regions food is likely to become stuck in the layngopharynx
- Piriform fossa - recess between central part of larynx and lateral lamina of thyroid cartilage
- Cricopharyngeus
From where to where does the larynx extend?
Laryngeal inlet to inferior border of cricoid cartilage
What is the function of the larynx?
Guards air passage during swallowing. Larynx rises and epiglottis closes to allow the bolus to slide down it and into the oesophagus
What cervical vertebrae does the upper surface of the thyroid cartilage mark? What can be found here?
c4 - bifurcation of common carotid and level of carotid body
How does the thyroid cartilage articulate with the hyoid bone nad the cricoid cartilage
via superior and inferior horns
What cervical level does the cricoid cartilage mark?
c6
What is the function of the arytenoid cartilage?
vocal cord movement
What is the conus elasticus? What is the upper free border of the cricovocal ligament?
lateral cricothyroid ligament. Upper free border is the vocal ligament.
What is found in the supraglottic space?
vestiblar folds (false vocal cords)
What is found in the glottis?
vocal cords and rima glottis (space between vocal cords)
What is found in the subglottic space?
Lower border of cricoid cartilage
What is the function of the infrahyoid and suprahyoid muscles?
Elevates or depresses larynx
What is the function of the vocal folds of the larynx?
Open and close glottis
What is the function of the aryepiglottic folds of the larnx?
Help close laryngeal inlet
What structures do the intrinsic muscles of the larynx act upon?
Vocal and aryepiglotic folds
What is the nervous supply of the intrinsic muscles of the larynx?
The Recurrent Laryngeal Nerve supplies the intrinsic muscles. The exception is the Cricothyroid Muscle, which is supplied by the External Laryngeal Nerve.
What are the 3 layers of the vocal cords?
- Stratified Squamous Epithelium
- Vocal Ligament
- Vocalis Muscle
Which muscles are responsible for the abduction and adduction og the vocal cords?
Abduction – Posterior Cricoarytenoid
Adduction – Lateral Cricoarytenoid and cricothyroid
What is the laryngeal nerves a subsidiary of?
Branches of vagus nerve
What nerves supply the sensation above and below the true vocal cords?
Above - superior laryngeal
Below - Recurrent laryngeal
What vertebrae does the left and right recurrent laryngeal descend to? Where does each nerve curve under?
Left - T4, under arch of aorta
Right - T2, under right subclavian
How does palsy of the recurrent laryngeal nerve present clinically?
hoarseness of the voice. Longer than 3 weeks is red flag
Give 3 possible causes of recurrent laryngeal palsy
Infection, GORD, apical lung tumour
What is the blood supply to the larynx and what are they branches of?
Superior and inferior laryngeal arteries which are branches of superior and inferior thyroid arteries.
What is the venous drainage of the larynx?
Superior and inferior laryngeal veins
superior Laryngeal –> superior thyroid –> internal jugular
Inferior laryngeal –> inferior thyroid –> left brachiocephalic
What 2 things can cause a laryngeal obstruction?
Inhalation of foreign body and tumour
In an emergency, where would you open an airway into the trachea?
Through the cricothyroid membrane, aka cricothyroidotomy
What is the afferent and efferent limb of the gag reflex?
Afferent - glossopharyngeal
Efferent - Vagus
In a patient with tonsillitis, which lymph node would you expect to be enlarged?
Tonsillar (jugulo-digastric)
What is a pharyngeal pouch?
Weakening between cricopharyngeus and thyropharyngeus muscles leading to diverticulum of pharyngeal mucosa between them
