Pharynx, Nasal Cavities, and Palate week 2 Flashcards
What is the relationship of the nasopharynx to the soft palate and nasal septu,? How does it communicate with the nasal cavity?
What is the relationship of the orpharynx to the soft palate and epiglottis? How does the oropharynx communicate with the oral cavity?
What blocks the nasopharynx during swallowing?
What is the relationship of the laryngopharynx to the epiglottis? How far inferior does the laryngopharynx exted?
Key concepts: The nasopharynx, oropharynx, and laryngopharynx are overlapping regions extending from the base of the skull to the larynx in the neck. The pharynx completes the posterior wall of the nasal, oral, and laryngeal cavities.
- The nasopharynx is above the soft palate and posterior to the nasal septum. It communicates with the nasal cavity through the choanae.
- The oropharynx lies behind the soft palate and epiglottis and communicates with the oral cavity via the fauces. During swallowing the soft palate and the uvula flip upwards to block the nasopharynx from the oropharynx so materials do not enter the nasal passages.
- The laryngopharynx lies behind and inferior to the epiglottis extending to the cricoid cartilage.
What are the 3 pharyngeal constrictor muscles? What do they attach to?
What plexus innervates the pharyngeal constrictor muscles? What nerves contribute to this plexus?
The pharyngeal constrictor muscles are 3 sac-like muscles that form the first part of the gut tube and have the ability to squeeze materials taken into the oral cavity down into the esophagus.
The superior pharyngeal constrictor attaches on the pterygomandibular raphe, the hamulus of the medial pterygoid lamina pharyngeal tubercle of the basilar portion of the occipital bone.
The middle pharyngeal constrictor attaches to the stylohyoid ligament, lesser and greater cornua of the hyoid bone and midline raphe.
The inferior pharyngeal constrictor attaches to the thyroid and cricoid cartilages and midline raphe.
The pharyngeal constrictors are innervated by the pharyngeal plexus which consists of glossopharyngeal (CN IX) and vagal (CN X) as well as postganglionic sympathetic fibers from the superior cervical ganglion.
Notice in attached pic that these muscles are incomplete anteriorly for openings of the nasal and oral cavities.
The pharyngeal raphe provides a midline anchor for the constrictor muscles.
constrictors
Identify the muscles.
What is the function of these muscles?
State the attachments of the muscles and what nerves they are innervated by.
The 3 longitudinal elevators act to elevate and assist the pharyngeal constrictors in closure of the oropharynx during swallowing.
The stylopharyngeus muscle attaches to the styloid process and posterior border of the lamina of the thyroid cartilage. In its path it passes through a gap between the middle and superior pharyngeal constrictors. The stylopharyngeus is the only muscle that is innervated by a motor component of the glossopharyngeal nerve.
The salpingopharyngeus muscle attaches to the opening of the auditory tube and blends in with the pharyngeal constrictors. Innervated by the vagus nerve.
The palatopharyngeus muscle attaches to the palatine fascia and blends in with the pharyngeal constrictors. Innervated by the vagus nerve.
In what part of the pharynx are the pharyngeal tonsil and auditory (Eustachian) tubes located?
What cartilaginous structure surrounds the Eustachian tubes?
Is the auditory tube normally open or closed? What is it during swallowing?
The nasopharynx is the region above the soft palate and posterior to the nasal septum. The choanae communicate between the nasopharynx and nasal cavity.
The roof of the nasopharynx houses the midline pharyngeal tonsil and auditory tubes (Eustachian or pharyngotympanic tube) in the lateral walls just above the soft palate. Their aperture is surrounded by the cartilaginous torus tubarius.
The auditory tube is normally closed, but during swallowing, it opens which allows the air pressure within the middle ear to equilibrate with the external air pressure.
Identify the parts of the pharynx.
Note that this is a posterior view.
What muscles close off the nasopharynx from the oropharynx during swallowing?
What are these muscles innervated by? What are their individual actions?
Elevation of the soft palate and uvula during swallowing - accomplished by tensor veli palatini (inn. by CN V), levator veli palatini (inn. by CN X-vagus) and musculus uvulae (CN X).
The levator veli palatini is responsible for elevation of the soft palate during swallowing.
The tensor veli palatini broadens the soft palate during swallowing.
Identify the labeled folds and the muscles contained within them.
State what structures the muscles extend between.
What lies between the 2 folds?
What nerves innervate the palate? What are these nerves branches of?
What provides SSA innervation to the posterior 1/3 of the tongue, palatine tonsils, and pharynx?
What provides SSA innervation to the epiglottis and pharynx?
- Palate - principal nerves are the greater and lesser palatine nerves (branches of CN V2).
- Posterior 1/3rd of the tongue-glossopharyngeal provides GSA and SSA innervation. CN IX also conveys GSA innervation from the palatine tonsils and the pharynx. Additionally, the Vagus nerve conveys GSA innervation from mucosa of the pharynx.
- The Vagus nerve conveys SSA innervation from the epiglottis and pharynx.
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Note that the sympathetic trunk is the most medial structure. Note the superior cervical ganglion-contains postganglionic fibers of sympathetic nerves innervating head and neck structures.
Branches of what arteries provide vascular supply to the pharynx and palate?
Name the branches of arteries that supply the pharynx and palate.
4 arteries with overlapping distribution.
- Lingual artery with dorsal and deep lingual branches.
- Maxillary artery with greater and lesser palatine branches.
- Facial artery with ascending palatine branch.
- Ascending pharyngeal artery with palatine branch.
During talking, chewing, etc transiently close off vessels. With overlapping distribution, ensures constant blood supply
Identify the cartilages of the nose.
Identify the numbered structures.
Identify the labeled structures.
What are the purposes of the nasal concha?
What do the lateral walls of the nasal cavity lead to?
The concha create turbulence, filter air (as things stick to mucous membrane), and humidify air.
The lateral walls of the nasal cavity also lead to the paranasal air sinuses.
Identify the numbered structures.
Identify the indicated structures.
note the frontal sinus anteriorly.
The NASAL SEPTUM divides the nasal cavity and provides support and a large surface area for filtering and warming inspired air. It has both cartilaginous and bony parts.
What are the 4 gateways into and out of the nasal cavity?
What passes through each?
4 Gateways into and out of the Nasal Cavity.
- Cribriform plate – transmits Olfactory nerve CN I and anterior ethmoidal nerve.
- Sphenopalatine foramen - communication between the nasal cavity and the pterygopalatine fossa. transmits: sphenopalatine branch of the maxillary artery; nasopalatine branch of the maxillary nerve (V2); superior nasal branches of the maxillary nerve (V2)
- Incisive canal - located in the floor of the nasal cavities; transmits nasopalatine nerve from the nasal cavity into the oral cavity; terminal end of the greater palatine artery from oral cavity into nasal cavity.
- Small foramina in the lateral wall – transmit branches of the infraorbital nerve of the maxillary nerve (V2); branches of the facial artery; branches from the greater palatine branch of maxillary nerve [(V2)
What branches of the external carotid artery supply the nasal cavity?
What branches of the internal carotid artery supply the nasal cavity?
State how these arteries enter the nasal cavity.
Note that there are numerous anastamoses among arteries in the nasal cavity.
External carotid artery:
- Sphenopalatine artery – from pterygopalatine fossa as a branch of the maxillary artery.
- Greater palatine artery – from pterygopalatine fossa as a branch of the maxillary artery.
- passes through the palatine canal and greater palatine foramen
- passes up through the incisive fossa to reach the nasal cavity
- Superior labial and lateral nasal arteries - originate from the facial artery.
Internal carotid artery:
- Anterior and posterior ethmoidal arteries
- originate in the orbit from ophthalmic artery
- enters nasal cavity through cribriform plate to supply the medial and lateral walls.
What veins drain the nasal cavities?
Venous drainage of the Nasal Cavities.
- generally follow the arteries.
- drain into the pterygoid plexus of veins.
- emissary veins are connections between the nasal veins and dural sinuses.
- Emissary veins in general are routes by which infections can track from peripheral regions into the cranial cavity.
- Note in attached picture that veins of the nasal cavity also drain into the cavernous sinus and facial vein.
What nerve conveys olfaction from the nose? How do these fibers pass into the cranial cavity?
What nerve(s) provide GSA innervation to the nasal cavities?
What nerves provide parasympathetic and sympathetic innervation to the nasal cavities?
Innervation of the Nasal Cavities.
Olfaction - CN I; fibers pass through cribriform plate to reach the olfactory bulb
General Sensation
• branches of the trigeminal nerve- V1 and V2
Autonomic
Parasympathetic
- CN VII - parasympathetic innervation of mucous glands and paranasal sinuses
- postganglionic parasympathetic fibers then join branches of V2 to reach target glands.
Sympathetic innervation
• spinal cord level T1; fibers synapse in superior cervical sympathetic ganglion.
What are the paransal sinuses? List all of them.
What openings are present within the nasal cavity?
The paranasal sinuses include the frontal, ethmoid, maxillary, and sphenoid. Secretions from the sinuses and nasolacrimal duct open into the nose.
Sinus
- sphenoid sinus
- posterior ethmoid sinus
- anterior and middle ethmoid sinuses
- frontal sinus
- maxillary sins
- nasolacrimal duct
Opening
- spehnoethmoid recess
- superior, middle, and inferior meatus
