Anatomy + Pain stuff Flashcards
Parasympathetic ganglia
1) Ciliary ganglion
Orbit - behind eyeball
CNIII → CNV1 → short ciliary nerves
Targets - ciliary muscle, pupil
Action - accommodation, constriction
2) Pterygopalatine ganglion
Pterygopalatine fossa
Nervus intermedius of CNVII → CNV2 mx & CNV1 lacrimal
Targets - lacrimal gland, mucous glands in nasal cavity, pharynx, palate
Lacrimation, secretion from nasal glands
3) Submandibular ganglion
Near angle of mandible, beneath FOM
Nervus intermedius of CNVII → chorda tympani → CNV3 lingual
Target: submandibular & sublingual glands’ salivation
4) Otic ganglion
Foramen ovale
CNIX → lesser petrosal → CNV3 - auriculotemporal
Target - Parotid
Salivation (secretion from parotid gland)
Ascending pathways
All 3-order neurons
CN 1,2,8 - pure sensory + 5,7,9,10 - mixed
Dental Pain, temp, crude touch: (trigeminal lemniscus pathway) spinal nucleus (synapses in MO, crosses over.)
Fine touch, vibration: (dorsal column) pontine nucleus (synapses in pons)
Proprioception: mesencephalic nucleus (synapses in midbrain)
Descending pathway
All 2-order neurons
CN 3,4,6,11,12 - pure motor + 5,7,9,10 - mixed
Location of nucleus determined by where CN is exiting through
Midbrain: 3,4, 5 sensory (mesencephalic nucleus)
Pons: 5 motor, 5 sensory (pontine nucleus), 6,7,8,9
Medulla: 5 sensory (spinal nucleus), 7 sensory, 10, 11, 12
Consequences of damage to pathway:
All other motor neurons: 80% contralateral supply, 20% ipsilateral
UMN - partial paralysis
LMN - complete paralysis
CN 7 - lower half of face: 100% contralateral supply
UMN - complete paralysis of contralateral
LMN - complete paralysis of ipsilateral
Describe the pain pathway resulting in pain pathway of:
1) 37
2) 11
- LHS inferior alveolar nerve stimulated → ascends and exits foramen ovale → reaches LHS trigeminal ganglion as the spinal nucleus (1st order neuron) → runs from the pons down to the medulla oblongata (synapses with the 2nd order neuron) → crosses over and runs up to RHS thalamus (synapses with 3rd order neuron) → reaches somatosensory cortex of the RHS post-central gyrus → pain registered
- RHS anterior superior alveolar nerve stimulated → ascends through foramen rotundum, reaches RHS trigeminal ganglion as the spinal nucleus (1st order neuron) → runs down through pons into medulla oblongata (synapses with 2nd order neuron) → crosses over and runs up to LHS thalamus where it synapses as 3rd order neuron → travels to LHS post-central gyrus somatosensory cortex of cerebrum → pain registered
Explain the consequences of damaging facial nerve when injecting 37.
Consequences:
Patient’s left eye will lose muscle tone, not able to blink/close eye.
Patient’s left lip will droop downwards
What happened:
During IANB administration, LHS lower motor neuron of the CNVII that affects the lower ½ of the face was anaesthetised/damaged.
100% contralateral rule applies to CNVII lower ½ of face: originally, UMN from RHS precentral gyrus → synapses with LMN at pons and 100% of the neurons will cross over to LHS of the tract
Sends signals to LHS effector organ/muscle - muscles of facial expression & orbicularis oculi
As such, when there is damage to the LMN of LHS CN7, there will be complete paralysis of the ipsilateral side → LHS facial muscles and LHS face droops + LHS eyes lose muscle tone.
Cranial nerves
Each cranial nerve:
Exits skull through:
Its functional component + Sensory territory for afferent/target organs for efferent.
Pure sensory - 1,2,8
Pure motor - 3,4,6,11,12
Mixed - 5,7,9,10
Special senses of sensory: 1,2,—7,8,9,10
Cavernous sinus contains: CN3,4,V1,6, internal carotid
Below: when I say sensation I mean of pain, temperature and crude touch
CNI - Olfactory nerve
Cribiform plate
SVA - smell
CNII - Optic nerve
Optic canal
SSA - sight
CNIII - Oculomotor
Supra-orbital fissure
GSE - muscles of orbit except superior oblique and lateral rectus
GVE - parasympathetic of ciliary ganglion
CNIV - Trochlear
SOF
GSE - superior oblique muscle
CNV1 - Opthalmic of trigeminal
SOF
GSA - Sensation of upper 3rd of face
CNV2 - Maxillary of trigeminal
Foramen rotundum
GSA - sensation of middle 3rd of face
CNV3 - Mandibular of trigeminal
Foramen ovale
GSA - sensation of lower 3rd of face
SVE - muscles of mastication, incl AB of DG
CNVI - Abducens
SOF
GSE - lateral rectus muscle
CNVII - Facial nerve
IAM → stylomastoid foramen
GSA - external ear sensation
Pterygopalatine fossa → chorda tympani - nervus intermedius
SVA - taste for anterior ⅔ of tongue
GVE - Parasympathetic for submd and pterygopalatine glands
Foramen lacerum → greater petrosal - nervus intermedius
SVE - muscles of facial expression and PBdigastric
CNVIII - Vestibulocochlear
IAM
SSA - hearing and balance
CNIX - glossopharyngeal
IAM
GSA - sensation of posterior ⅓ tongue and pharynx
SVA - taste
SVE - stylopharyngeus muscle
GVE - otic ganglion (parotid)
GVA - baroreceptors in carotid sinus
CNX - vagus
Jugular foramen
GVE - parasympathetic innervation
GSA - sensation of throat and ear
SVE - constrictor muscles of throat
GVA - baroreceptors in aortic arch
CNXI - accessory nerve
Jugular foramen
GSE - neck muscles
SVE - some vagus components
CNXII - hypoglossal nerve
Hypoglossal canal
GSE - muscles of tongue
Muscles of mastication
Masseter
Superficial head → origin: Mx process of zygomatic bone
Deep head → zygomatic arch of temporal bone
Both attach to angle of mandible, superficial is more superior on ramus
Bilateral contraction leads to elevation of mandible
Unilateral contraction leads to medial mvmt
Superficial head protrudes, deep head retracts
Temporalis
Origin: Temporal fossa along inferior temporal line of skull
Insert: coronoid process of mandible
Deep end attaches directly to coronoid, the superficial end runs along the zygomatic arch
Contraction: elevation, retrusion of Md
Lateral pterygoid
Upper head
Originates from infratemporal surface and infratemporal crest of the GW of sphenoid,
Inserts at joint capsule of TMJ
Lower head
Originates from lateral aspect of LatPt plate of sphenoid
Inserts at pterygoid fovea on neck of condyloid process of mandible
Bilateral contraction → depression and protrusion of mandible
Unilateral contraction leads to → TMJ disc moves anteriorly and medially
Medial pterygoid
Superficial head - Origin: maxillary tuberosity & pyramidal process of palatine bone
Deep head - Origin: medial surface of LatPt plate of sphenoid
Both Inserts: medial aspect of angle of Md
TMJ
Joint is surrounded by a capsule attaching to articular eminence, articular disc & neck of condyle.
Articular disc is a fibrous extension from the capsule.
Disc divides joint into
superior synovial cavity (joins to Md fossa of temporal bone) and
inferior synovial cavity (behind it and the posterior disc is retrodiscal tissue - aka bilaminar zone - which counters the forward pull of LatPt)
Anterior disc joins to superior head of Lat Pt
Submandibular triangle, carotid triangle, submental triangle boundaries.
Submandibular triangle
Bounded by anterior and posterior bellies of digastric, body of mandible (mylohyoid and hyoglossus muscle)
Carotid triangle
Bounded by posterior belly of digastric, superior belly of omohyoid, and sternocleidomastoid m.
Submental triangle
Bounded by anterior bellies of digastric and hyoid bone
Sinuses
4 paranasal sinuses:
Maxillary sinuses
Frontal sinuses
Ethmoid sinuses
Sphenoid sinuses
Lymph nodes, lymphatic system, lymph drainage
Right lymphatic duct drains the upper right torso and arm. LHS Thoracic duct drains the rest of the body.
Superficial LN collect lymph from the face and drain into deep cervical LN.
Lymphatic capillaries → afferent lymphatic vessels → lymph nodes → efferent LV → lymphatic trunks → lymphatic ducts
Facial nodes (buccinator, nasolabial, malar, Md nodes)
Drains: lateral eyelid, nose, cheek
Flow: facial nodes → subMd nodes → jugulodigastric node → inf deep lat cerv nodes → thoracic (LHS) or right lymphatic duct
Pericervical lymphatic circle (occipital, mastoid, parotid, subMd, submental nodes)
Drains: scalp, skin of neck, eyelids, root of nose, ear cheek
Flow: PCL circle → deep/superf lat cervical nodes → supraclavicular nodes → jugular trunk → thoracic or right lymphatic duct
Lingual nodes
Drains tongue
Flow: Lingual nodes → subMd & submental nodes → jugulodigastric node → deep lat cerv nodes → supraclavicular nodes → jugular trunk → thoracic or right lymphatic duct.
Submental nodes
Drains chin, lower lip, cheek, gingiva around incisors, dorsal tongue, oropharynx
Flow: submental nodes [→ subMd nodes → deep lat cerv nodes]/[jugulo-omohyoid node*] → jugular trunk → thoracic/right lymphatic duct
Submandibular nodes
Drains subMd and subLi glands, FoM, tongue, palate, gingiva, teeth, skin of eyelids, lips nose chin
Flow: subMd nodes → deep lat cerv nodes → supraclavicular nodes → jugular trunk → thoracic/right lymphatic duct
Squamous cell carcinoma
* common sites
* Risk factors
Common sites:
Lower lip, anterior FOM, lateral border of tongue, retromolar region, buccal mucosa gingiva, palate
Impt to palpate lymph nodes
Risk factors:
Tobacco consumption: carcinogens, genetic mutation
Sun exposure - UV alters DNA bonds, by forming ROS
Alcohol consumption: byproduct of alcohol metabolism causes DNA damage
Carcinogenic substances eg N-Nitrosis, mycotoxins & causes keratosis, epithelial detachment, mucosal ulceration
HPV infection: high risk strains integrate into DNA → alter growth
Diet - nutrient deficiency impacts immune system & ability to repair DNA
Nitrosamines - found in processed food, alcohol, cigarette
Age: increase in accumulated damage and amount of exposure to risk factors
Investigating pain
COLDSPA
Character, onset, location
Duration, severity
Precipitating factors, associated factors
Questions
Does pain keep you up at night → rating severity
Does pain worsen when running/lying down → if yes suspect maxillary sinusitis
Do you notice if you are clenching or grinding your teeth / Do you wake up with a sore jaw, headaches → bruxism
Relevant tests:
Radiographs
Visual examination of suspected tooth/area eg for caries, cracks, of gums for inflammation
Pulp tests - cold test, EPT electric pulp test
Frac finder / Wedge test (bite on wedge)
(Not common) selective anaesthesia - if tooth goes numb and pain is gone, pain is odontogenic.
Non-odontogenic causes of dental pain – referred pain.
Maxillary sinusitis
Relates to rapid postural changes
Roots of Mx teeth can communicate/lie close to Mx sinus
Sinus inflammation → puts pressure on roots of mx teeth, can cause tooth pain
Middle ear infection
Can cause referred pain to tooth & vv
Temporal tendonitis
Inflammation of tendon temporalis → pressure → pain
TMJ related issues
Jaw joints, overuse of masticatory muscles
Cluster headaches/migraines
Rare
Trigeminal neuralgia
Usually associated with CN5.2 and 5.3
Rarely bilateral
Sudden onset, triggered by mild stimulation of specific trigger zone along distribution of cranial nerve (washing face, wind, brushing teeth)
Occipital, glossopharyngeal neuralgia
Injury of stylomandibular ligament
Giant cell arteritis
Post-herpetic neuralgia
