Mouth, tongue, and jaw Flashcards
How can the healthy mouth be divided?
- vestibule - sulci between the lips/cheeks and the teeth
- oral cavity proper - the space inside and including the teeth
What are the main parts of the oral vestibule?
- buccal sulcus (between cheeks and teeth)
- gingivia (gums)
- labial sulcus (between lips and teeth)
- lining mucosa
What are the main parts of the mouth?
- vermillion border (edge of lips)
- uvula
- palatoglossal arch
- palatopharyngeal arch
- soft palate
- palatine tonsil
What key clinical issues can affect the mouth?
- oral thrush
- poor oral hygiene and aspiration pneumonia risk
- radiotherapy changes
What are the important features of the dorsal surface of the tongue?
- lingual tonsil
- sulcus terminalis
- filiform papillae
- fungiform papillae
- circumvallate
What does the sulcus terminalis do?
divides the tongue into posterior and anterior
What are papillae?
little bumps on the tongue to help grip food while chewing. some contain taste buds
What are the different papillae on the dorsal tongue and their roles?
- circumvallate - contain taste buds
- fungiform - contain taste buds
- filiform - no taste buds
What are the main features on the ventral surface of the tongue?
- lining mucosa
- lingual veins
- lingual frenulum
- sublingual papillae
What do the sublingual papillae do?
allow saliva to drain into the oral cavity
What is ankyloglossia?
a short frenulum - tongue tie
What are the sets of muscles in the tongue?
intrinsic and extrinsic
What are the features of the extrinsic muscles of the tongue?
- attach to the skull and tongue
- change the position of the tongue
What are the features of the intrinsic muscles of the tongue?
- both attachments are within the tongue
- change the shape of the tongue
What are the extrinsic muscles of the tongue?
- palatoglossus
- styloglossus
- genioglossus
- hyoglossus
What is the CN innervation of the palatoglossus muscle?
CNX - vagus
What is the CN innervation of the styloglossus muscle?
CNXII - hypoglossal
What is the CN innervation of the hyoglossus muscle?
CNXII - hypoglossal
What is the CN innervation of the genioglossus?
CNXII - hypoglossal
What is the action of the palatoglossus muscle?
elevates posterior tongue and depresses soft palate
What is the action of the styloglossus muscle?
retracts tongue and elevates sides of tongue
What is the action of the genioglossus muscle?
wide range of action, protrudes, flattens
What is the action of the hyoglossus muscle?
depresses tongue and sides of tongue
What are the intrinsic muscles of the tongue?
- superior longitudinal
- inferior longitudinal
- transverse
- vertical
Which CN innervates the intrinsic muscles of the tongue?
CNXII - hypoglossal
What is the action of the superior longitudinal muscle?
shortens tongue and curls apex upwards
What is the action of the inferior longitudinal muscle?
shortens tongue and curls apex downwards
What is the action of the transverse muscle?
narrows and lengthens tongue
What is the action of the vertical muscle?
broadens and flattens
Which CN provides motor innervation to tongue?
hypoglossal - XII
Which CNs give sensory innervation to tongue?
- glossopharyngeal (IX) - supplies all posterior sensation
- Chorda tympani (branch of facial nerve VII) - supplies taste and sensation to anterior 2/3
- lingual (V3 of trigeminal) - supplies sensation to anterior 2/3
Which key clinical issues can affect the tongue?
- glossectomy
- neurological events
What are the key features of the hard palate?
- alveolar ridge
- rugae
- tightly bound oral masticatory mucosa
What is thought to be the function of the rugae?
friction for control when pushing bolus through oral cavity
What are the main muscles of the soft palate?
- levator veli palatini
- tensor veli palatini
- palatoglossus
- palatopharyngeus
What is the action of the levator veli palatini?
elevates the soft palate
What is the action of the tensor veli palatini?
tenses soft palate
What is the action of the palatopharyngeus?
depresses soft palate
How is the levator veli palatini related to the ear?
When eating and chewing, it contracts, opening the auditory tube and allowing it to drain, and equalises the pressure in the middle ear
What key clinical issues can affect the palate?
- cleft lip and palate
- velopalatal insufficiency
- palatal resection
What are the movements of the TMJ?
- rotate (axis through condyle) - relatively small amount of movement
- slide - head of condyle moves onto articular eminence
What are the key parts of the mandible?
- coronoid process
- ondylar process
- head
- neck
- ramus
- angle
- body
What are the main parts of the TMJ?
- glenoid cavity
- articular disc
- articular eminence
- lateral pterygoid
- condylar process
What is the function of the articular disc?
- attaches lateral pterygoid muscle to posterior aspect of joint
- pulled forward by lateral pteryoid to stabilise joint when head of condyle is on articular eminence
What are the main ligaments of the TMJ?
- temperomandibular/lateral
- stylomandibular
- sphenomandibular
What is the main role of TMJ ligaments?
proprioception and define range of movement
What key clinical issues can affect TMJ?
- TMJ dysfunction
- abscess/infection
- trismus
What are the muscles of mastication?
- 2 superficial muscles - masseter and temporalis
- 2 deep muscles - medial and lateral pterygoid muscle
What CN supplies muscles of mastication?
motor branches of V3 trigeminal
What are the features of the temporalis?
- elevates and retracts the mandible
- attached to lateral aspect of skull and coronoid process of mandible
What are the features of the masseter?
- powerful elevator of mandible
- attached to zygomatic arch and lateral aspect of mandibular ramus
What is the role of the lateral pterygoid?
protrudes mandible
Which muscles depress the mandible?
Suprahyoid and infrahyoid
How is the mandible depressed?
- infrahyoid and suprahyoid contract together
- hyoid bone stabilised
- suprahyoids pull down on mandible
- lateral pterygoids protrude mandible
- results in movement forwards and down
Which other muscles are involved in mastication?
- buccinator
- obicularis oris
- tongue
What is a good tooth position?
- upper molars overhang lower by half a tooth
- upper incisors overhang lower by 2mm
What is the normal range of movement in speech?
- no lateral excursion
- open 2cm
- protrusion less than 1cm
- retraction less than 1cm
What are the key clinical issues affecting the muscles of mastication?
- mandibulectomy/maxillectomy
- anscess/infection
- neurological events