W1: LA Intro Flashcards
What is the whole point of learning LA?
To be able to safely and effectively administer local anesthetic preparations to patients
– Need to apply well: knowledge of anatomy, pharmacology, physiology bc we do LA regularly
Course outline of LA, how is it broken down?
BOH1 (semester 2): theory
- BOH2 (semester 1): 4 practical days
- sharps handling/infection control
- intra-oral landmarks and positioning
- 2x mannequin injections, they have sensors (not on each other any more)
REVIEW
7 lectures, last one is review
Nut shell of history part 1:
What happened to guy who first injected LA?
Cocaine discovery?
- killed his wife
- cocaine= numb, opthamologist put in eye to perform surgery
Who performed the first inferior alveolar nerve block?
used cocaine, intro LA to dentistry. block is most known LA technique
What other anaesthetic developed aside from cocaine?
began to develop synthetic LA procaine, then ligno (most famous and most used), then others
What dental pain could patients present with?
- come from tooth= odontogenic pain
- chronic= more than 2 months
- referred from muscle, joints like TMJ and
- rare= pain in orofacial that is neuropathic (nerves got damaged)
we tx mainly tooth pain
LA is used alot, why?
no pain
When do we use LA?
-there to provide pain relief for procedure
- topical (b4 rubber dam), resto (into dentine), under gum scale and curette, exo
- ppl have diff tolerances so adjust
What must we consider when administering LA?
label
- maxilla tuberosity easy to feel, last molar bulge
- teeth in alveolar process
- beside mandible, maxilla= largest face bone, has holes, porosity evident in photo which is adv for LA to pass through bone to get through teeth
label
- LHS of maxilla
- canine eminence can be seen, smile wide, lift cheek/lip up, bulge above canine, alveolar mucosa stretches thin over there
- zygnomatic process can be felt, cheek bone, feel through soft tissue
Avoid LA
- when pt does not want
- when no pain involved: shallow class 1 occlusal pit, few seconds. advise no pain. better bc not numb for hours
Where is the maxillary nerve? what is it’s role?
purely sensory no motor
Pulpal and buccal innervation is supplied by branches of which nerve? What do they supply
branches of Maxillary nerve
post middle AN
ant and superior Alveolar N
they run above alveolar process (all of them, see in yellow) thus superior
summary for alveolar
PSA= buccal the gingiva bone PDL, pulpal tissue of all molars, soft tissues, supp up to 1st molar but not mesial buccal root of 1st molar
MSA= move forward middle, supp buccal tissues, PMs, mesial buccal root of 1st molar, not present in everyone (30% have this)
ASA= in ppl who dont have MSA
What holes should you note on the hard palate?
hard palate
ant 2/3= pair of palantine processes of maxilla, joined at ML at mid palatal suture
- post 3rd= horizontal plates of palatinebone,
there is demarcation of ant 2/3 and post 1/3 of hard palate.
- ant= nasal incisor foramin, just behind upper centrals
- post 3rd of HP bilaterally, greater palantine foramen, important holes for nerves
Is MSA present in everyone?
no 70% dont have this nerve, so what nerve supplies teeth in middle? ASA supplies in place.
Describe distribution of nerve innervation above alveolar bone:
PSA goes up to all molars ex. MB root of 1st molar and everything else is MSA (30%) OR ASA (70% prev)
What nerve comes out of infraorbital nerve?
Adult dentition
ASA
eyes, done AB, pulp, PM then mesial buccal root.
Kids
- pulpal teeth of all ABCD
- lil branch to mesial sptum but dw
What nerve branches of MN into palantine fossa?
IN primary dentition, only E is supplied by?
PSA and the rest is ASA supplied
Primary teeth
E= PSA
everything else = ASA
How is palate innervation divided
what innervates posterior palatine (most of palate)?
GPN: 2 pairs, main nerve supp soft tissue and bone of hard palate. comes from GP fossa and travels anteriorly.
What other nerves aside from palate and alveolar bone must we consider? What complimentary artery should we watch out for when wanting to innervate PSA?
know artery, don’t want to cause hematoma (balloon blood, huge swelling quickly)
- watch out for PSAA, above alveolar ridge at the back
Is maxillary nerve M or S
purely S
Is there a technique for blocking PSA?
yes but not taught, huge risk of artery damage
What supplies the lacrimal gland, nasal glands, and palatal (minor)
salivary glands for secretomotor?
What is largest and strongest bone in face?
mandible
- can get fractures in sports tho
Which bone is thicker?
Mandible has less porosity, solid, smooth, so LA there wont get through bone to reach teeth. so have to block nerve at mandibular foramin * there is like a spiky bony prom called lingula marking MF*
Which only area of mandible has porosity?
anterior, similar to maxilla bone
What nerve supplies mandible?
What is largest branch of TN?
mandibular
Key diff btw Man and MAx of TN
Max= sensory
Man= mixed
IAN importance, if you block that one nerve what can you achieve?
IAN supplies all (ONLY ONE SIDE) mandibular teeth, pulps, soft tissue, corner of lips, huge chunk
How can IAN supply diff?
a. 1
2. lil br
3. divides 2
variations
key: all supplied by 1 IAN
What is being pointed?
IAN enters mandible by lingula hole, then runs in mandibular canal supplying all teeth w diff branches.
point= direction we would point needle
ONce IAN enters mandible by MF inside mandible, travel forward
runs teeth, exits mental foramin and branch to 2 terminal branches
1. out of mental foramen= mental nerve supp buccal soft tissue anterior of foramen
2. stays inside mandible= incisive nerve= pulps, canine, mandibular teeth and incisors
What is the Inferior alveolar canal?
yellow= IAN, starts mandibular FM and exit mental FM
blue/red= blood vessels (IAA and IAV)
NV bundle, runs through bone canal IAC
Mandibular innervation includes…
front= mental nerve
back= long buccal,
but if hole around canine then long buccal will increase and include PMs
Where is mental foramen located?
variable. just adj to apex 2nd PM, can be more distal around 6’s or 4-3’s
hole forward= less long buccal coverage vice versa
front of MF= mental nerve, back = long buccal
You blocked the mental nerve which is next to the mental foramen, however patient is still not numb. Why may this be so?
some sensation in injection may be coming from long buccal nerve bc it crosses over the mental nerve at the point next to the mental foramen…
long buccal supplies
- buccal gingiva upto and including 2nd PM assuming mental foramen is around 2nd PM
What nerve supplies tongue?
sensation to floor mouth, all tongue
- if tongue goes numb, can go tingly
What nerve hitchhikes along with lingual nerve?
Chorda tympani- allows taste to ant 2/3 tongue
Lingual nerve importance
sensation + taste
Post nerve for taste
pharyngeal nerve
If you gave an IAN block but pt. is still not numb, what does this mean?
There is accessory innervation in area (i.e. Mylohyoid Nerve supplies the area)
supplies sensation to Mandibular molar
- give IAN and failed to numb on Mand molars despite blocked nerve of Mylohyoid, yet 1 tooth not num means that accessory innervation
accessory innervation
- give IAN and failed to numb on Mand molars despite blocked nerve of Mylohyoid, yet 1 tooth not num means that accessory innervation
Name landmarks for IAN
Buccal M, tissue in between, important landmark for IAN,
behind ligament, dark shadow is mandibular foramen = IAN
cannot see it, its a bony landmark covered by fat
Behind Raphe is
Foramen, IAN
What structures should we note on medial ramus of mandible?
- sphenomandibular lig- too thick = bad for LA
- foramen
- parotid gland
- Inf alv BV
- lots more
just need to target small bony landmark
Infratemporal fossa - boundaries
Maxillary artery gives off what artery that we should watch out for?
gives off IAA runs with IAN
IAA, main artery we worried about when giving IAN
What is venous supply of face?
- vein comes in bundle so next to A and N
common cause of aspiration is on artery or vein?
Vein.
Would want to avoid artery
safer into vein than artey
What Intra-oral anatomy must you consider when performing- buccal infiltration, where should you inject/ NOT inject?
above attached gingiva in alveolar gingiva
aim: height of mucal buccal fold
NEVER attached gingiva= see how firm it attaches, not much tissue, really thin, painful,, hit bone straight away, too far from apex
if you aspirate and see blood
- stop injecting
- change cart and reposition
What landmark do we rely on for IAN blocks?
bc we know behind raphe= 2 muscle, mesial= buccinator and back supperior pharangeal constrictor.
open wide, see band of tissue, running behind top of molar to bottom molar
thats the PR
behind that raphe is mandibular foramen
other landmark: PT depression, can see ‘shadow’, thats where we want to inject
inject from opp side, parallel to occlusal plane
Process of IAN block
open wide as can
see raphe (pic)
look for along raphe TP depression
inject there
but correct direction is contralat PM, parallel occlusal
When cant we see raphe
buccal fat, huge tongue
raphe depression is where?
what dense bone ridge is DB on last molar?
Floor of mouth
- press or yawn lower mouth- saliva squirts out
Maxilla summary
Maxilla has 3 nerves only 2 need to know ASA and PSA (most ppl no MSA)
for primary ASA supp everything not E (PSA one tooth E)
Buccal
-All Buccal ASA until MB 1st molar root, rest is PSA
-palatal= 3 holes, big hole behind incisors= palantine supp ant 1/3, rest post has 2 nerves Greater Palantine nerve
note only one palantine nerve
Mandible
IAN= all teeth
buccal= behind MF= long buccal
before= mental N branch of inferior alveolar
Which nerve travels towards the to the
facial nerve (CN VII)?
Facial nerve joins with what to supply what?
