VIVA – Anatomy – Oral cavity Flashcards
What is the boundary between the oral cavity + oropharynx?
Palatoglossal arch, circumvate papillae, junction of hard and soft palate
Are the circumvalate papillae part of the oral cavity or oropharynx?
Oral cavity
What is innervationof circumvalate papillae?
Glossopharyngeal nerve
- Sensation and taste
- Cell bodies in glossopharyngeal ganglia in jugular foramen
- Carries parasympathetic secremotor fibres to mucosal glands (with relay in lingual ganglia in mucosa)
What are the landmarks for the parotid duct?
- 5cm long
- Crosses masseter, thru buccal fat pad and pierces buccinators
- Lies on middle 1/3 of line between intertragic notch and midpoint philtrum
- Opens opposite 2nd upper molar
Draw a tooth and label it’s parts
What is the nerve supply of the teeth?
- Dentine, enamel and cementum are all denervated
- Pulp and periodontal ligament share their nerve supply – does not necessarily supply overlying gum
- Upper molars = Posterior superior alveolar nerve
- Upper Pre-molars = Middle superior alveolar nerve
- Upper Canine and Incisors = Anterior superior alveolar nerve
- Lower molars and premolars = Inferior alveolar nerve
- Incisor branch to canines and incisors
Describe Dental anaesthesia techniques
- Maxilla
- Topical anaesthetic on tooth gingiva will penetrate and anaesthetise for dental procedures
- Buccal aspect infiltration allows drilling
- Palatal aspect for extractions needed
- Mandible
- Infiltration only effective for incisiors
- Inferior alveolar nerve block needed for extractions and other teeth
- Adjacent buccal and lingual gingiva needs infiltration to allow for extractions
How many teeth are there? Adult
32
- 2 x midline incisors
- 1 canine
- 2 premolars – 2 cusps
- 3 molars
- upper molars = 3 roots, 4 cusps
- lower molars = 2 roots, 5 cusps
- 8 teeth in each half jaw and 32 in total
How many teeth are there? Child
20 – 5 in each half jaw
- 2 x incisors
- 1 x canine
- 2 x molars à replaced by premolars
How are teeth numbered?
2 digit numbering system, first number represents a tooth’s quadrant and the second number represents the number of the tooth from the midline of the face. For permanent teeth, the upper right teeth begin with the number, “1”. The upper left teeth begin with the number, “2”. The lower left teeth begin with the number, “3”. The lower right teeth begin with the number, “4”. For primary teeth, the sequence of numbers goes 5, 6, 7, and 8 for the teeth in the upper right, upper left, lower left, and lower right respectively.
Palmer and FDI systems.
adult
upper right - 1x upper left - 2x
18 17 16 15 14 13 12 11 | 21 22 23 24 25 26 27 28
R ————————————————— L
48 47 46 45 44 43 42 41 | 31 32 33 34 35 36 37 38
lower right - 4x lower left - 3x
deciduous
upper right - 5x upper left - 6x
55 54 53 52 51 | 61 62 63 64 65
R ——————————— L
85 84 83 82 81 | 71 72 73 74 75
lower right - 8x lower left - 7x
I - Incisivi
C - Canini
P - premolar
M - molar
What is the Angle classification of occlusion?
Measure where the position of the 1st maxillary molar is (mesiobuccal cusp (front) of the upper first molar should rest on the mesiobuccal groove of the mandibular first molar)
A=normal
B=class I = neutral but problems with spacing, crowding, over or under eruption
C=class II = retrognathia (ant to mesiobuccal cusp)
D=class III = prognathia (post to post cusp)
What are the layers of the hard palate?
Stratified squamous epithelium
Lamina propria
Mucoperiostum
- Strongly adherent mucous membrane over ant palate, united to the periosteum à secured by multiple fibrous tissue pegs (Sharpeys fibres)
- Glandular tissue present over the horizontal process of the palatine bone with no sharpeys fibres – bone smoothly polished
How do you perform a sphenopalatine block?
25G needle at 45deg
Bent at 25mm
1.5ml 1:100,000 adrenaline injected slowly into greater palatine foramen
To find GPF – opposite 2nd molar on hard palate – feel intra-orally for depression
Name the intrinsic muscles of the tongue
- Wholly within the tongue with no bony attachment
- Alter shape of tongue
- Superior Longitudinal –shortens
- Inferior Longitudinal
- Transverse – narrows the tongue
- Vertical –elongated with transverse, midline groove for swallowing
Name the extrinsic muscles of the tongue, their attachments and actions
Genioglossus
- Largest forming bulk of tongue
- From superior mental spine
- Fibres radiate out to insert into mucous membrane of tongue with inferior fibres also passing down to hyoid
- Contraction of lowest fibres draw the tongue forward
Hyoglossus
- Arises from length of greater horn of hyoid bone and hyoid body lateral to genioglossus
- Extends up as a thin sheet
- Interdigitates at right angles with styloglossus fibres
- Attached to side of tongue
- Anterior and posterior borders are free
- Lateral to the hyoglossus from superior down lie
- Lingual nerve
- Submandibular duct
- Hypoglossal nerve
- Deep to the posterior border are
- Glossopharyngeal nerve
- Stylohyoid ligament
- Lingual artery
- Acts to draw the sides of the tongue downwards
Styloglossus
- Arises from lower anterior styloid process and upper stylohyoid ligament
- Runs forward below superior constrictor
- Inserts into lateral tongue interdigitating with hyoglossus
- CNIX is parallel to and deeper than the lower border
- Acts to retract the tongue
Palatoglossus
- Descends from inferior surface palatine aponeurosis
- Forms palatoglossal arch
- Inserts onto side of tongue
- Elevates posterior tongue, closes the oropharyngeal isthmus and aids initiation of swallowing. This muscle also prevents the spill of saliva from vestibule into the orophyranx by maintaining the palatoglossal arch.
How are branches of lingual artery related to hyoglossus?
Discuss the embryology of the tongue? inc Mucosa, Muscles
- week 4
- median tongue bud = tuberculum impar rostral (above) to F. caecum in the floor of primordial pharynx – 1st pharyngeal arch
- 2 lateral lingual swellings develop from mesenchymal of 1st branchial arch
- enlarge and form the ant 2/3 of the tongue. The plane of their fusion is the median sulcus of the tongue, and internally by the fibrous lingual septum.
- The median bud degenerates (overgrown)
- Posterior 1/3 (pharyngeal part):
- Two swellings that develop caudal to the foramen caecum.
- Copula (Latin: bond or tie) fusion of the ventromedial parts of the 2 pair of ph arches.
- Hypobranchial eminence caudal to the copula from the ventromedial parts of the 3rd and 4th ph arches
- At birth, the entire tongue sits in the mouth, and by 4yo, the post 3rd sits in the oropharynx
- Muscles derived from sub-occipital myotomes
- Migrate forward with nerve supply (Hypoglossal) – ventrally around ECA and ICA but medial to IJV
- Epithelium derived from parts of 1st, 3rd and 4th arches
- Presulcal mucosa from midline tuberculum impar and lateral lingual swellings of 1st arch
- Post-sulcus mucosa from midline hypobranchial eminence of 3rd arch (Glossopharyngeal) à Posterior tongue à 3rd arch overgrows 2nd, therefore IX nerve supply to mucosa (valleculae from hypobranchial eminence).
- Small contribution from 4th arch (internal laryngeal nerve)
Draw a coronal cross section through the floor of the mouth
