H&N 10: The Pharynx Flashcards
What are the divisions of the pharynx?
Nasopharynx, oropharynx, laryngopharynx
Where does the nasopharynx run from and to?
From the base of the skull to the upper border of the soft palate
What is contained within the nasopharynx?
Pharyngeal tonsil (adenoids) and orifice of the Eustachian tube
Where does the oropharynx run from and to?
From the soft palate to the superior border of the epiglottis
What is contained within the oropharynx?
The palatine tonsils between the palatoglossal (anterior) and palatopharyngeal (posterior) arches
Where does the laryngopharynx run from and to?
From the epiglottis to the oesophagus (at the level of the inferior border of the cricoid cartilage)
What is contained in the laryngopharynx?
A small depression called the piriform fossa (common site for food and foreign bodies to become stuck)
Which vertebrae love posterior to each section of the pharynx?
C1 posterior to nasopharynx
C2,3 posterior to oropharynx
C4,5,6 posterior to laryngopharynx
What are the internal muscles of the pharynx, and their innervation?
Stylopharyngeus, CN IX
Palatopharyngeus, CN X
Salpingopharyngeus, CN X
What is the function of the internal muscles of the pharynx?
To shorten and widen the pharynx and elevate the larynx during swallowing
What are the external muscles of the pharynx, and their innervation?
Superior, middle and inferior circular muscles
All innervated by the vagus nerve
All contract peristaltically to push bolus into oesophagus
What is the common tendinous origin of the external circular pharynx muscles?
Pharyngeal raphe
What is Killian’s dehiscence?
A small area of weakness between the two muscle belly components of the inferior constrictor
If pharynx is incoordinated during swallowing/ UOS fails, part of the pharyngeal mucosa can herniate through Killian’s dehiscence to form the pharyngeal pouch. Food can trap here -> dysphagia, bad breath, choking
What is the innervation of the muscles of the pharynx?
All vagus nerve innervated, except the stylopharyngeus which is innervated by glossopharyngeal nerve
What is the sensory innervation of the areas of the pharynx?
Nasopharynx: CNV2
Oropharynx: CN IX
Laryngopharynx: CN X
What are the stages of swallowing?
- Oral
Voluntary, makes the bolus and pushes it to oropharynx - Pharyngeal
Involuntary, soft palate elevated to seal off nasopharynx (opens ET), epiglottis closes over larynx, bolus moves through pharynx by contractions of constrictors, relaxation of UOS, supra hyoid muscles elevate pharynx and larynx - Oesophageal
Involuntary, into GI system
What are some causes of dysphagia?
Stroke/ dementia/ Parkinson’s
Which tonsils swell in tonsillitis?
Palatine tonsils
Which lymph nodes will swell in tonsillitis?
Jugulodigastric
What is Waldeyer’s tonsillar ring?
A ring of lymphoid tissue consisting of pharyngeal tonsil, palatine tonsils and lingual tonsils
What are the suprahyoid muscles?
- 4 pairs of strap like muscles that all elevate the hyoid bone during swallowing
- stylohyoid, geniohyoid, digastric, mylohyoid
What are the infra hyoid muscles?
4 muscles that act to depress the hyoid bone
In the superficial plane: sternohyoid and omohyoid
(Both innervated by anterior rami of C1-3, branch of ansa cervicalis)
In the deep plane: sternothyroid and thyrohyoid
Sternothyroid innervated by anterior rami of C1-3
Thyrohyoid innervated by anterior rami of C1, within hypoglossal nerve
Where is the thyroid gland?
In the anterior neck, between C5 and T1
2 lobes that are connected by an isthmus
Wraps around the cricoid cartilage, and lies inferior to the thyroid cartilage of the larynx
Bound to the pretracheal fascia along with trachea, oesophagus and pharynx
What is the vascular supply of the thyroid gland?
2 paired arteries on both the left and right
Superior thyroid artery (first branch of ECA) supples superior and anterior
Inferior thyroid artery (from thyrocervical trunk) supples posterior and inferior
