the pharynx Flashcards
what is the pharynx?
a muscular tube that extends from the base of the skull to the oesophagus
what are the three regions that the pharynx is divided into?
the nasopharynx
the oropharynx
the laryngopharynx
where does the nasopharynx lie?
posterior to the nasal cavities and above the soft palate
where does the oropharynx lie?
posterior to the mouth, between the soft palate and epiglottis
where does the laryngopharynx lie?
posterior to the larynx to blend w/ the oesophagus
where does the laryngopharynx blend w/ the oesophagus?
at around C6 vertebral level
what important feature is contained in the lateral wall of the nasopharynx?
the auditory tube (aka eustation tube)
what is the function of the eustation tube?
it communicates w/ the middle ear and allows air to pass between the pharynx and middle ear to equalise pressure either side of the tympanic membrane
what are the boundaries of the oropharynx?
roof: soft palate
floor: posterior third of the tongue, lingual tonsil and glossoepiglottic folds
anterior: mouth
posterior: C2/C3 level
lateral: palatoglossal and palatopharyngeal folds w/ palatine tonsil
which 2 muscles form the arches at the back of the mouth?
palatoglossus and palatopharyngeus
which 2 structures attach to the larynx?
the aryepiglottic fold and the thyrohyoid membrane
how many constrictor muscles are w/in the pharynx?
3
what does the superior constrictor form part of?
the nasopharynx and the oropharynx
describe the constrictor muscles
there are 2 parts to each constrictor muscle
there is a right and left side of the constrictors that meet in the posterior midline at a fibrous joining called a rafae
what are the functions of the constrictor muscles?
all of the constrictor muscles push the food bolus downwards but the superior constrictor also raises the pharyngeal wall and pull it forwards in the nasal cavities to close the nasopharynx and prevent food from passing towards the nose
explain the motor innervation to the constrictor muscles
all constrictor muscles are provided w/ motor innervation by the vagus nerve running in the pharyngeal plexus
what does the middle constrictor contribute to?
the wall of the oropharynx
what doses the inferior constrictor contribute to?
the laryngopharynx and completes the pharynx and joins the oesophagus
how does the inferior constrictor differ from the others?
it has muscular fibres that pass towards the midline in a similar fashion to the other constrictor muscles but also has fibres that are more circular in nature
what is the thyropharyngeal part of the inferior constrictor?
the fibres that pass towards the midline
what is the cricopharyngus part of the inferior constrictor?
the more circular fibres
what is the function of the cricopharyngeus part of the inferior constrictor?
help close off the end of the pharynx to prevent air from passing into the oesophagus
which nerve innervates all of the constrictor muscles?
the vagus nerve as it forms part of the pharyngeal plexus
which branch of the vagus nerve innervates cricopharyngeus?
the external laryngeal branch
in addition to the constrictor muscles what other muscles attach to the pharynx?
there are 3 longitudinally orientated muscles that attach to the pharynx
what are the three longitudinal muscles that attach to the pharynx?
stylopharyngeus
salpingopharyneus
palatopharyngeus
explain the innervation to the longitudinal muscles that attach to the pharynx
stylopharyngneus is innervated by the glossopharyngeal nerve
the others are innervated by the pharyngeal plexus
what is the function of stylopharyngeus?
it helps to elevate the pharynx to more effectively pull food into the pharynx and close off the nasopharynx
what is the function of palatopharyngeus?
elevates the pharynx
explain the act of swallowing
the food gets moulded by the tongue and the hard palate and then gets pushed to the back of the mouth to be swallowed
the soft palate is then raised and the pharynx elevated to ensure food passes away from the nasopharynx
the larynx is raised and the epiglottis passively bends over the larynx as the bolus of food passes it
the ayerepiglottic folds move together to ensure food passes into the laryngopharynx and not the larynx
what nerve passes through the thyrohyoid membrane?
the superior laryngeal nerve
what nerve passes between the oesophagus and trachea and then inferior to the inferior constrictor of the pharynx?
the recurrent laryngeal nerve
where does general sensory innervation to the pharynx come from?
the maxillary division of the trigeminal nerve
the glossopharyngeal nerve
the vagus nerve
which 2 cranial nerves contribute to the pharyngeal plexus?
CN 9 and 10
what does the pharyngeal plexus supply?
the pharynx
describe the arterial supply to the pharynx
the upper regions of the pharynx are supplied from branches of the maxillary artery (greater palatine and pharyngeal) and the ascending branch of the ascending carotid artery
describe the venous drainage of the pharynx
the pharyngeal veins form a plexus that communicates w/ the facial and internal jugular veins
describe the lymphatic drainage of the pharynx
lymph drains to retropharyngeal and paratracheal nodes and then to deep cervical nodes
what are the preverterbal muscles?
longus coli
longus capitis
rectus capitis anterior
rectus capital lateralis
what is the function of longus capitis?
acts to flex the head on the neck
what is the innervation of longus capitis?
anterior rami of C1-C3
what is the function of longs coli?
acts to flex the neck and inferior oblique fibres allow rotation of the neck
what is the innervation of longus coli?
anterior rami of C2-C6
what is the function of rectus capitis anterior and laterals?
flex the atlantooccipital join
what is the innervate of rectus capitis anterior and laterals?
anterior rami of C1
where does the sympathetic chain pass from / to?
from the base of the head to the ganglion impar on the coccyx
what is the function of the sympathetic ganglia?
allow sympathetic innervation to spread beyond T1 to L1, L2 levels
describe the superior cervical ganglion
it is a large ganglion that gives fibres that wrap around the neck and carotid arteries to supply the structures in the head
it contributes to the pharyngeal plexus and to the cardiac plexus
which cervical ganglion forms the ansa subclavia?
the middle cervical ganglion
where does the ansa subclavia lie?
it is a loop around the subclavian artery
where is the stellate ganglion (T1 ganglion) found?
in the inferior cervical ganglion
