Oral Cavity Flashcards
(25 cards)
What are the boundaries of the oral cavity formed of
Lateral walls - buccinators
Roof - hard and soft palate
Floor - formed by number of muscles, tongue and soft tissue
Describe where the oral cavity begins and ends. What forms these parts
Oral cavity begins as oral fissue -> extends posteriorly to the orophargyneal isthmus
Oral fissue - opening to the mouth
Isthmus is an arch formed by soft palate above and upper surface of the tongue below. Anterior and posterior arches form sides of isthmus - formed by palatoglossus (anterior) and palatopharyngeal (posterior)
How is the oropharyngeal isthmus closed off from the oral cavity during chewing
Contraction of palatoglossus and palatopharyngeal muscles pulls soft palate down towards back of the tongue to close oropharyngeal isthmus
What is found between the palatoglossal and palatopharyngeal arches
Tonsillar fossa - palatine tonsil is found within
Where do the salivary ducts drain into the oral cavity
Submandibular drains via Wharton duct - under tongue
Parotid drains via Stensen/parotid duct
Sublingual have many excretory ducts per gland
How are the muscles of the tongue divided and what does each division do
Intrinsic - lie within tongue. Run longitudinally, vertically and transversely. Alter shape of tongue
Extrinsic - change position of the tongue. Anchor tonuge to surrounding structures: hyoid and mandible below, styloid process and soft palate above
What are the extrinsic muscles of the tongue and which is used to test a CN (which CN)
Genioglossus - protrudes tongue. Used to test hypoglossal nerve (CN XII)
Hypoglossus
Styloglossus
Palatoglossus
What is the nerve innervation to the tongue - sensory and motor
Hypoglossal nerve innervates all muscles of tongue except palatoglossus (vagus)
Anterior 2/3 - general sensation by lingual branch of Vc. Chorda tympani fibres supply special sensory
Posterior 1/3 - general sensory glossopharyngeal. Carries both general and special sensory
Describe the pharynx
Muscular tube that continues as the oesophagus
Arises from skull base -> descends down to level of C6 where it beocmes oesophagus
Is divided into nasopharynx, oropharynx and laryngopharynx
Is narrowest inferiorly where it becomes the oesophagus
What is the nasopharynx
First part of pharynx
Lies superior to soft palate
Nasal cavities open into it through two choanae
C1 lies posteriorly
Orifice of Eustachain tube and pharyngeal tonsil are found
What is the oropharynx
Second part of the pharynx
Extends from level of soft palate to superior border of epiglottis
C2 and C3 lie posteriorly
Palatine tonsils lie either side in the tonsillar fossa
What is the laryngopharynx
Third part of the pharynx
Extends from epiglottis to the oesophagus at level of the inferior border of cricoid cartilage
Lies immediately behind the larynx - C3-6 lie posteriorly
Piriform recesses are found on each side fo laryngeal inlet - epiglottis diverts materal into piriform recesses to prevent food entering larynx
Externally, what do the walls of the pharynx consist of
Walls of pharynx externally consist of circular superior, middle and inferior constrictors
These contract and relax sequentially to propel food into the oesophagus
Posteriorly these muscles form pharyngeal raphe - common midline, tendinous insertion
What does the inferior constrictor consist of
Two muscles bellies: thyropharyngeus and cricopharyngeus
This corresponds to where muscles arise from thyroid and cricoid cartilages
What is Killian’s dehiscence
Area between the muscle bellies of the inferior constrictor
If there is incoordination of pharynx during swallowing, pressure within pharynx can rise and cause part of pharyngeal mucosa to herniate through Killian’s dehiscence
Forms pharyngeal pouch/diverticulum
Internally, what do the walls of the pharynx consist of and what are the names of the muscles
Internally, walls of pharynx consist of three longitudinal muscles that act to shorten and widen the pharynx during swallowing and speaking
Muscles:
- Stylopharyngeus
- Palatopharyngeus
- Salpingopharyngeus - helps open Eustachian tube
What do the muscles that form the internal wall of the pharynx do
They directly or indirectly connect to thyroid cartilage -> more larynx up
Help elevate pharynx and larynx during swallowing
What is the motor and sensory supply of the pharynx
Motor - vagus supplies muscles of pharynx and soft palate - exception is stylopharyngeus (CN IX)
Sensory:
- Nasopharynx - maxillary branch of trigeminal
- Oropharynx - glossopharyngeal nerve
- Laryngopharynx - vagus
What are some complications of adenoiditis (think about what it may obstruct)
May obstruct passage of air from nasal cavities into nasopharynx -> causes mouth breathing and nasal tone to speech
Can block eustachain tube -> lead to otitis media and otitis media with effusion
Name some oral cavity pathologies
Sialolithiasis - salivary duct stones
Non-otological causes of otalgia
Peritonsillar abscesses
Cranial nerve probelsm in oral cavity
Tonsillitis
Describe sialolithiasis
Stones can form in ducts draining salivary glands causing pain and swelling
Submandibular most commonly affected
Swelling and pain can fluctuate in relation to eating
Infection may occur due to stasis of saliva
Caused by dehydration and reduced salivary flow
Why might patients have non-otological causes of otalgia
Nerves supplying sensory innervation to pharynx also supply sensory innervation to ear -> referred pain
Consider non-otological causes of otalgia if present with otalgia and normal ear
Places where referred pain may originate: tongue, oropharynx, cervical spine, oesophagus, nose, sinuses, TMJ
What is tonsillitis, what is the most common cause and what are the symptoms
Inflammation of the palatine tonsils
Virus is most common cause but strep throat (e.g. strep pyogenes) is most common bacterial cause
Symptoms: pain, sore throat, pain/difficulty swallowing, bad breath, swollen cervical lymph nodes
Why might a patient develop peritonsillar abscesses and what are the symptoms
Can develop due to aerobic or anaerobic bacteria
Can be secondary to poorly/untreated tonsillitis
Pushes uvula off to the side due to tissue around tonsils becomes inflammed
Symptoms: sore throat, bad breath, drooling, difficulty opening mouth, voice changes
