Session 9- oral cavity, TMJ and development of the nose and face Flashcards Preview

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Flashcards in Session 9- oral cavity, TMJ and development of the nose and face Deck (116):

What are the boundaries of the oral cavity?

  • Roof
    • Hard and soft palate
  • Floor
    • Tongue and other soft tissues
  • Lateral walls
    • Cheek (buccinator muscles)
  • Anterior
    • Oral fissure (space between lips_
  • Posterior
    • Oropharyngeal isthmus (opening to oropharynx)


What is the soft palate made up of?

  • Muscular
  • Palatoglossus muscle forms the palatoglossal arch (anterior arch)
  • Palatopharyngeus muscles forms the palatopharyngeal arch (posterior arch)
  • Also forms part of the uvula


What happens to the soft palate when we yawn?

It is elevated 


Describe the innervation of the muscles of the soft palate

  • The right and left vagus nerves
  • The pharyngeal branch of the nerve


If there is a lesion in the pharyngeal branch of the vagus nerve on the left side what is seen?

  • Deviation of the uvula to the right 
  • The uvula is pulled away from the side of the damaged area by muscles on the unaffected side 


What is the orophryngeal isthmus?

Opening to the oropharynx


What is the difference between the oral vestibule and the oral cavity proper?

  • Oral vestibule- space between the teeth and cheeks/lips
  • Oral cavity proper- from teeth to the ring made by the palatopharyngeal arch, the uvula and the tip of the epiglottis


Why is the gag reflex not tested routinely?

It is unpleasant for the patient 


What is the afferent and efferent limb of the gag reflex?

  • Afferent:
    • Glossopharyngeal 
    • Back of tongue/throat, uvula, tonsilar area
    • N.B. The afferent limb is stimulated on one side of the tongue but the reflex arch occurs on both sides so the efferent response in bilateral 
  • Efferent:
    • Vagus- pharyngeal muscles of the soft palate contract and there is a rise in the soft palate 


Describe the names of the teeth, from those found in the centre of the mouth to those at the back

  • Central incisor
  • Lateral incisor
  • Canine
  • First pre-molar
  • Second pre-molar
  • First molar
  • Second molar
  • Third molar 


What is the sensory supply to the lower jaw?

  • The inferior alveolar nerve (branch of CN V3) 


When can the lower alveolar nerve be affected leading to loss of sensation in the lower jaw?

  • In mandibular fracture
  • Also site of anaesthesia in dental surgery 
    • Inferior alveolar nerve runs close to lingual nerve so there can also be loss of sensation in the tongue 


What are the extrinsic muscles of the tongue?

  • Styloglosus
    • Retracts and elevates the tongue
  • Genioglossus
    • Protrudes the tongue
  • Hyoglossus
    • Retracts and depresses the tongue
  • Palatoglossus 
    • Does a mixture of functions 


Which of the extrinsic muscles of the tongue forms part of the soft palate?



What is the main roll of the extrinsic muscles of the tongue?

  • Help to anchor the tongue to the hyoid bone and mandible 
  • Allow the tongue to change position 

N.B. they all end in 'glossus'


What are the directions of the fibres of the intrinsic muscles of the tongue which allow it to change shape?

  • Superior longitudinal and inferior longitudinal
    • Curl the tongue up/down
  • Vertical
    • flattens the tongue
  • Transverse 
    • Pull it in 
  • There is also a septum between the intrinsic muscles of each half of the tongue 


What is the nerve supply of muscles of the tongue?

  • Palatoglossus 
    • Vagus nerve
  • All other muscles
    • Hypoglossal nerve, CN XII


Which nerves provide sensory innervation to the tongue?

  • Internal laryngeal nerve, CNX
  • Glossopharyngeal nerve, CN IX 
    • General and sensory 
  • Lingual nerve (CN V3)
    • general sensory 
  • Chorda tympani (CN VII)
    • Special sensory 
    • Branch of facial nerve 


If there is a lesion in a nerve supplying the tongue in which direction does deviation of the tongue occur?

  • towards the side of the lesion 
  • Muscles of the unaffected side push it this way


Describe the opening of the salivary glands into the oral cavity

  • Parotid Gland 
    • Stenson's duct 
  • Submandibular Gland
    • Wharton's duct
  • Sublingual
    • Multiple ducts into the bit under the base of the tongue 


What type of stones are most salivary duct stones? Which duct do they commonly affect and why?

  • Calcium 
    • saliva can crystalise and block salivary ducts stopping them from draining
  • Submandibular most commonly affected
    • Produces salivary that is comparatively thicker than parotid gland 
    • Sublingual stones are rare 


How do salivary gland duct stones often present?

  • Pain or swelling of the affected gland at meal times (as glands are stimulated to produce more saliva but it can't get past the blockage so the gland swells)
  • You may be able to see a wharton's duct stone as you can see where the duct opens


Describe the treatment of salivary gland duct stones

  • small stones resolve spontaneously 
  • But they commonly need removal 


Which tonsils are involved in Waldeyer's ring?

  • Adenoid
  • Tubal tonsil
  • Palatine tonsil
  • Lingual tonsil


What is tonsilitis? How does it present?

  • Inflammation of the palatine tonsil 
  • Patients present with sore throat and odynophagia/dysphagia 
    • Difficult to swallow as they are so enlarged 
  • Tonsils appear enlarged, red and erythmatous 


What are the features of viral and bacterial tonsilitis?

  • Viral 
    • rhinovirus, adenovirus 
    • Accompanied by symptoms of URTI e.g. dry cough 
  • Bacterial
    • e.g. beta-haemolytic strep
    • Accompanied by cervical lymphadenopathy, fever, pus


What is quinsy?

  • Peritonsilar abscess
  • Severe complication of bacterial tonsilitis
  • Usually strep pyogenes
    • Can be staph aureus, H.influenza or mixed flora 


What is the presentation of quinsy?

  • Patients typically systemically unwell 
  • Trismus (hot potato voice)
  • May drool due to dysphagia 
  • May have painful, limited movement of jaw


Is qunisy often uni or bilateral? What does it look like?

  • Unilateral
  • Appears red, erthymatous and inflamed 
  • Blocks view of posterior arch and there is loss of the anterior arch 
  • If the lesion is big the uvula can deviate away from it


What is the treatment of quinsy?

  • Same day referral to ENT 
  • Needs to be drained and antibiotics given 


What type of joint is the temporomandibular joint (TMJ)? What is the articulation?

  • A modified synovial hinge joint between the cranium and mandible 
  • Articulation:
    • Condyle for mandible 
    • Articular tubercle of the temporal bone 
    • Mandibular fossa 


What is prioritised in the TMJ, movement or stability?

  • Movement 
  • There is a relatively loose joint capsule 


Which ligaments support the TMJ?

  • Lateral ligament 
    • Temporomandibular ligament 
    • On the outside of the mandible
  • Stylomandibular ligament
    • From styloid process to just posterior to angle of mandible 
  • Sphenomandibular ligament 
    • From sphenoid bone to lateral mandible


Which muscles are involved in movement of the TMJ?

  • Temporal 
  • Masseter
  • Medial pterygoid
  • Lateral pterygoid
  • Supra hyoid
  • Infra hyoid


which muscles are involved in elevation and depression of the jaw?

  • elevation
    • Temporal, masseter, medial pterygoid
  • Depression 
    • Lateral pterygoid, supra/infrahyoid
    • Although mostly due to gravity 


Which muscles are involved in protrusion and retrusion of the jaw?

  • Protrusion 
    • Lateral pterygoid
  • Retrusion 
    • Temporal


Which muscles are involved in lateral movement of the jaw (e.g. in chewing)?

  • Temporal on same side
  • Pterygoids of opposite side
  • masseter 


What are the muscles of mastication and which nerve are they supplied by?

  • Temporalis, masseter, pterygoids
  • Mandibular branch of trigeminal nerve (V3)


what occurs in lock jaw? how is it treated?

  • Mandibular condyle comes out of fossa and moves anteriorly getting stuck 
  • Use a stack of tongue depressors and get the patient to bite down on them. This loosens the fibres; the jaw is then put back by moving it posterioly and inferiorly


what is a common cause of TMJ dislocation?

Lateral blow to the chin when the mouth is open 


Describe a TMJ dislocation. what must we also  look for?

  • Causes anterior dislocation on the same side as blow
  • Head of mandible is anterior to the articular tubercle 
  • Need to check for fracture on the opposite side of jaw 


As well as dislocation and lock jaw what other TMJ disorders are there?

  • Pain around the joint is often a presenting complaint
    • pain is in area supplied by V3 (as this supplies joint)
  • Differentials:
    • Temporal arteritis- type of vasculitis which can lead to loss of eyesight
    • Bruxism (teeth grinding)
    • Osteoarthritis of TMJ e.g. due to chronic bruxism
    • Inter-articular disc degeneration (may need operation)


Which social and psychological factors can increase risk of TMJ disorders?

  • Psychological
    • Anxiety
  • social
    • Excessive alcohol and sleep disorders


What is the infra-temporal fossa?

  • Irregularly shaped space deep and inferior to the zygomatic arch and deep to the ramus of the mandible


what is found in relation to the infra-temporal fossa:

  • Superiorly 
  • Posteriorly
  • Laterally 
  • Medially 
  • Inferiorly 
  • Anteriorly

  • Superiorly 
    • Inferior to greater wing of sphenoid
  • Posteriorly
    • Temporal bone
  • Laterally 
    • Ramus of mandible
  • Medially 
    • Lateral pterygoid plate of sphenoid
  • Anteriorly
    • posterior maxilla 


Which muscles are found in the infra temporal fossa?

  • Temporal muscle (inferior part)
  • Laterla and medial pterygoid 



Which vascular structures are found in the infra-temporal fossa?

  • Artery: maxillary 
  • Venous: pterygoid venous plexus (communicates with caverous sinus so infection can lead to cavernous sinus thrombosis)


Which nerves are found within the infra temporal fossa?

  • Mandibular
  • Inferior alveolar
  • Lingual
  • Buccal
  • Chorda tympani
  • Otic ganglion 


What does the mandibular branch of the trigeminal nerve give off and what do these innervate?

  • Inferior alveolar nerve
    • Lower teeth 
    • Continues as mental nerve and supplies sensory to the chin
  • Lingual
    • sensory to anterior 2/3rds of tongue 
    • Also carries chorda tympani fibres from the facial nerve for special sensory to the same area
  • Buccal 
    • Sensory to cheek and buccal gum


What does the otic ganglion supply?

Parasympathetic to the parotid gland 


What can occur in the infra temporal fossa?

  • Isolated infection e.g in diabetic patients
  • Tumours (rare) e.g. meningiomas 


which nerve can be blocked through the infra temporal fossa?



What is the main contributor to the overall growth of the head?

The expansion of the cranial part of the neural tube which goes on to become the brain 


What other systems is the development of the face linked to?

  • The cranial gut tube
  • The outflow of the developing heart (aortic arch and vessel system)
  • Development of the sense organs 
    • and the need to separate the resp tract from the GI tract



What are neural crest cells?

  • They are derived fom the lateral border of the neuroectoderm and they become displaced and enter the mesoderm just before the neural tube forms
  • The cells migrate widely and contribute to a variety of head and neck structures 


What are the major morphological features of the face?

  • Palpebral fissures (openings for the eyes)
  • Oral fissure
  • Nares
  • Philtrum 


Describe the development of the facial skeleton

  • Due to neural crest cells of the first pharyngeal arch 
  • They migrate and populate the mesoderm core of the arch and drive facial skeleton formation 


What do the muscles of mastication and muscles of facial expression derive from?

  • Muscles of mastication 
    • Mesoderm of first pharyngeal arch 
  • Muscles of facial expression 
    • Mesoderm of 2nd pharyngeal arch 


What does each pharyngeal arch contain?

  • Artery, vein and cranial nerve 
  • Mesenchyme core with neural crest cells
  • Ectoderm covering
  • Endoerm lining


Where is the frontonasal prominence? Where do the primordia of the eyes begin developing?

  • It overlies the ventro-lateral part of the forebrain (cranial neural tube)
  • The primordia of the eyes begin development on the lateral sides of the FNP 


Where is the stomatodeum?

  • Small depression with the buccopharyngeal membrane in the middle of it 
  • There is no mesoderm here
  • It gives us the oral fissure 


What does the FNP go on to give?

Forehead, bridge of the nose, nose and philtrum


What are the two prominences which make up the 1st pharyngeal arch and what do they go on to give?

  • Maxillary prominence
    • Gives cheeks, lateral upper jaw and lateral upper lip
  • Mandibular prominence
    • Gives lower lip and jaw 


For the formation of the mature face what must occur?

  • Fusion of tissues
    • Stomatodeum 
    • FNP
    • Maxillary prominence
    • Mandibular prominence 


Describe the formation of nasal pits

  • Nasal placodes appear on the FNP
  • There is growth of ectoderm causing the placodes to sink down into the FNP forming nasal pits
  • On either side of the nasal pits are medial and lateral nasal prominences 


What happens to the medial nasal prominences?

  • They are pushed towards each other by the growth of the maxillary prominences
  • At the same time the nasal pits keep deepening and the nostrils form 
  • Maxillary prominences fuse with the medial nasal prominences and the medial nasal prominences fuse in the midline
    • At this point there is collaboration between the FNP tissue and maxillary prominences 


What does the fusion of the medial nasal prominences form?

  • The intermaxillary segment 
    • Labial components: philtrum 
    • Upper jaw: 4 incisors
    • Palate: primary palate 


As we all the primary palate anteriorly what else makes up the majority of the palate?

  • The secondary palate
    • Derived from palatal shelves which are derived from maxillary prominences


  • Describe the formation of the primary palate

  • Between the nasal pit (in FNP) and oral cavity is an oronasal membrane (just connective tissue) but this ruptures to give an opening
  • As the medial nasal prominences are pushed tpwards each other the primary palate is formed
    • Also contributes to the formation of the lip and jaw


Describe the development of the secondary palate and nasal septum

  • The maxillary prominence gives rise to 2 palatal shelves
  • These grow vertically down into the oral cavity on each side of the developing tongue (which is kind of in the way)
  • The mandible grows allowing increase in size of the oral cavity and 'drop' of the tongue 
  • The two palatal plates then grow towards each other and fuse in the midline
  • The nasal septum develops as a midline down growth and ultimately fuses with the palatal shelves 


Describe the dual origin of the lip and palate

  • Intermaxillary segment 
    • Medial nasal prominence becomes the philtrum and primary palate
  • Maxillary process
    • Becomes the fused palatal plates 


What is lateral cleft lip and cleft lip/cleft palate?

  • Lateral cleft lip
    • Failure of fusion of the medial nasal prominence and maxillary prominence 
    • Involves only the lip
  • Cleft lip/cleft palate
    • Same as above but combined with failure of palatal shelves to meet in the midline
    • Can lead to newborn having problems suckling and speech development problems 


What is the fate of the following facial prominences:

  • FNP
  • Medial nasal
  • Lateral nasal
  • Maxillary
  • Mandibular

  • FNP
    • Forehead, bridge of nose, medial and lateral nasal prominences
  • Medial nasal
    • Philtrum, primary palate, mid upper jaw
  • Lateral nasal
    • Sides of the nose
  • Maxillary
    • Cheeks, lateral upper lip, secondary palate, lateral upper jaw
  • Mandibular
    • Lower jaw and lip


When does development of the eyes begin and why?

  • 4th week
  • This is v early as they are an outgrowth of the brain and this begins developing first 


Describe the outgrowth of the forebrain which will go on to form the eyes

  • They grow out to make contact with the overlying ectoderm 
  • The optic vesicle (from the cranial neural tube) then grows out towards the surface to make contact with the lens placode (which goes on to develop into the lens)
  • The lens placode invaginates and pinches off 


What is the retina derived from?

  • The diencephalon (forebrain)


The eye primordia are positioned on the side of the head. How do they end up at the front and why?

  • Growth of the maxillary prominence and FNP pushed everything towards the midline
  • This allows binocular vision 


What does the external auditory meatus develop from? What about the tissue of the  external ear?

  • The 1st pharyngeal cleft (this remains to act as the meatus)
  • The tissue of the external ear is derived from the 1st and 2nd pharyngeal arches which are on either side of the cleft


Where do the ears begin development and how do they get to their final position?

  • Begin development in equivalent of neck of embryo (inferior to the mandible)
  • As the mandible grows the ears ascend to the side of the head to lie in line with the eyes 


Why are neural crest cells so important in the development of the face?

  • They are required for the growth of the mandible
  • This is needed for positioning of the ears, formation of the tongue and palate 


What are all chromosomal abnormalities associated with?

  • External ear abnormalities 


Which placode gives rise to each of the senses?

  • Vision
    • Optic/lens placode
  • Smell
    • Nasal placode
  • Hearing and balance 
    • Otic placode


Where are the otic placodes? Describe their development

  • On posterior of embryo
  • There is thickening of ectoderm and pit formation and they invaginate to form the auditory vesicles
    • Gives rise to membranous labyrinth:
      • Cochlea
      • Semi-lunar canal system
      • Allows balance and hearing


What is the safe level of alcohol consumption in pregnancy?

There is no known safe level 


What 2 conditions can alcohol in pregnancy give rise to? What is the combined incidence?

  • Foetal alcohol syndrome
    • Due to severe alcohol abuse
  • Alcohol related neurodevelopmental delay
  • 1/100 births 


What is particularly sensitive to alcohol in pregnancy?

  • Neural crest migration (leads to abnormalities in facial skeleton)
  • Development of the brain


What are some of the characteristic facial features of foetal alcohol syndrome?

  • Smooth philtrum 
  • Thin upper lip
  • Small head (as less development of the brain)
  • Low nasal bridge
  • Short nose
  • Small eye openings 


What important role do buccinator muscles play?

  • Keep food between the teeth when chewing 


What is the oropharyngeal isthmus formed by?

  • Superiorly: soft palate
  • Inferiorly: upper surface of the tongue
  • Sides: anterior and posterior pillars of the fauces 
    • Formed by palatoglossal and palatopharyngeal muscles 


Palatoglossus and palatopharyngeus run in the palate. What does their contraction during chewing cause?

  • Pulls the soft palate down towards the back of the tongue, closing the oropharyngeal isthmus, ensuring that food stays in the oral cavity when chewing


What lies between the palatopharyngeal and palatoglossal pillars?

  • Tonsilar fossa
  • This contains the palatine tonsil 


What is the muscular structure of the tongue covered in?

Mucous membrane


What do the intrinsic muscles of the tongue attach to? What about the extrinsic muscles?

  • Intrinsic
    • They blend with the extrinsic muscles
    • (do not attach to bone)
  • Extrinsic
    • Hyoid bone
    • Mandible
    • Styloid process 
    • Soft palate


why does the tongue recieve afferent innervation from a number of cranial nerves? Describe this innervation

  • Due to different embryological origins (pharyngeal arches 1,3 and 4)
  • Anterior 2/3rds of tongue
    • General/common sensation
      • Lingual nerve (branch of V3 of the trigeminal)
    • Special sensory
      • Fibres of chorda tympani branch of facial hitch hike on lingual nerve 
        • Also supplies secretomotor (parasympathetic) fibres to salivary glands
  • Posterior 1/3rd of tongue
    • General and special
      • Glossopharyngeal nerve (CN IX)
    • Small portion of posterior tongue (base-near the epiglottis) receives sensory and taste from vagus 


What divides the tongue into its anterior and posterior parts?

  • Sulcus terminalis
    • V shaped sulcus behind which is the pahryngeal part of the tongue
    • Sulcus projects posteriorly with a small pit, the foramen cecum (embryological remnant) at its apex 


On inspection of cranial nerve X why is the patient asked to open their mouth wide and say 'ahh'?

  • The ulvula is being inspected for any deviation 
  • If there is deviation this indicates weakness of the contralateral soft palate indicating cranial nerve X lesion


What do hypoglossal nerve lesions cause?

  • Deviation of the tongue towards the side of the lesion 


What do the 5 prominences fold around to form the face?

The stomatodeum


Where do the nasal placodes develop?

The ventrolateral aspect of the FNP


What is a placode tho?

  • An area of ectoderm that starts to thicken and differentiate itself from its surrounding tissue to give rise to sensory strucutres 


Where can clefts affect?

Lips, palate, nose


When can clefts of the lip (without involvement of the palate) be diagnosed?

  • At the scan at 20 weeks
  • Or after delivery


How many babies does cleft lip and palate affect in the UK?

  • 1 in 700
  • Most common facial birth defect 
  • They can be corrected with surgery as soon as possible to minimise potential impact on the infant 


How does a branchial cyst  develop?

  • Incomplete fusion of the second pharyngeal arch over the other arches allows perisistence of the cervial sinus
  • This leaves an open channel for communication between the sinus and the external environment via the skin
  • This gives rise to a branchial sinus
  • Sometimes a communication can occur between the sinus and inner pharyngeal pouch (where palatine tonsil develops)
  • If the sinus partially closes (remains a space but with no communication with body surface), this gives rise to a branchial cyst


When do branchial cysts normally present?

  • In 2nd decade of life
  • Often arise after an infection or minor trauma causing the cyst to swell and become apparent 
  • Present as smooth, non-tender soft masses along the anterior border of the sternocleidomastoid


How many deciduous and permanent teeth are there and at what age do they begin to errupt?

  • Two sets of teeth develop in the jaw
  • Deciduous (primary) are first set to errupt
    • Start to errupt at 6 months 
    • Once fully errupted there are 20
    • Begin to fall out and are replaced by permanent teeth
  • By age of 12 most permanent teeth have erupted (excluding 3rd molar (wisdom teeth) which usually erput between 17 and 21 years 
  • By early adulthood (21) all permanent teeth should have erupted
  • There are 32 permanent teeth 


Describe the direct pupillary light reflex

  • Light detected by photoreceptors in retina
  • Optic nerve (afferent nerve)
  • Pre-tectal nucleus in the brainstem
  • Edinger Westphal nucleus in the brainstem
  • Parasympathetic fibres carried on the oculomotor nerve (efferent nerve)
  • Sphinter pupillae muscle of iris (target tissue)


Other than pupillary light reflexes what else is done to assess optic nerve function?

  • Visual fields
  • Visual acuity


What is the function of the macula?

  • Provides highest acuity 
  • Point of retina for central vision 


  • An injury causes hyperextension of the neck. What cervical vertebrae is likely to have been damaged?



Between which 2 cervical vertebrae is there no intevertebral disc?

C1 and C2


What can lung cancer in the apex of the nerve affect and cause?

  • Can infiltrate and involve sympathetic nerves destined for the head and neck
  • The action of sympathetic nerves will mostly relate to the function of the eyelid and eye causing:
    • Incomplete ptosis and constricted pupil
    • (as unopossed parasympathetic innervation of sphincter pupillae)


What supplies sensory innervation to the chin and lower lip?

Inferior alveolar nerve 


Compared with peripheral oedema seen in heart failure how does tissue fluid accumulating in lymphoedema differ?

A greater proportion of protein in tissue fluid secondary to lymphoedema