Anatomy 5 & 6 Flashcards
1
Q
face characteristics from
A
- underlying bone structure
- deposition of fatty tissue
- colour and effect of ageing on skin
- abundance, nature and placement of hair
2
Q
CNV1 scalp and face innervation
exit point
A
- area over forehead
- upper eyelid
- most of nose
- exits through superior orbital fissure
3
Q
CNV2 scalp and face innervation
exit point
A
- part of cheek
- lower eyelid
- upper lip
- exits through foramen rotundum
4
Q
CNV3 scalp and face innervation
exit point
A
- most of temporal region
- remainder of cheek
- lower lip and chin
- exits through foramen ovale
5
Q
muscles of facial expression
some are arranged as
A
- sphinctors
- dilators
- around facial orifices
6
Q
muscles of facial expression generally anchored to
A
- bone or fascia on one end
- skin on the other
- allows them to produce facial expression
7
Q
which muscles of facial expression are sphincters
A
- orbicularis oris
- orbicularis oculi
8
Q
muscles of facial expression innervation
A
- either via posterior auricular branch of facial nerve
- or via parotid plexus which gives off 5 terminal branches of facial nerve
- CNVII
9
Q
CNVII exits cranium/enters skull via
exits skull via and what does it give off
A
- enters skull/exits cranium via the internal acoustic meatus
- exits via stylomastoid foramen where two branches are given off (post. auricular and digastric)
- main nerve enters parotid gland and gives off 5 branches
10
Q
what pharyngeal arch do muscles of facial expression originate
A
2nd pharyngeal arch
11
Q
what nerve innervates occipital belly of occipitofrontalis
A
- posterior auricular nerve
- branch of CNVII
12
Q
what nerve innervates frontal belly of occipitofrontalis
A
- temporal nerve
- branch of CNVII
- most superior of the 5 branches from plexus in parotid gland
13
Q
what nerve innervates orbicularis oculi
A
- temporal to superior portion
- zygomatic to inferior portion
- both are branches of CNVII
14
Q
what nerve innervates upper lip muscles
A
- zygomatic
- branch of facial nerve CNVII
15
Q
what innervates buccinator muscle
A
- buccal nerve
- branch of CNVII
16
Q
what innervates orbicularis oris muscle
A
- buccal to superior part
- margina mandibular to inferior part
- both are branches of CNVII
17
Q
what nerve innervates platysma
A
- cervical nerve
- branch of CNVII
18
Q
occipitofrontalis originates/inserts into/action
A
- frontal belly originates from epicrania aponeurosis and inserts into the skin/subcutaneous tissue of eyebrow and forehead
- occipital belly originates from lateral 2/3 of superior nuchal line and inserts into epicranial aponeurosis
- retracts the scalp (occipital belly)
- wrinkle forehead and elevate eyebrows (frontal belly)
19
Q
orbicularis oculi originates/inserts into/action
A
- palpebral part originates from medial palpebral ligament and inserts into the lateral palpebral raphe at the ligament
- orbital part originates from nasal part of frontal bone, frontal process of maxilla and medial palpebral ligament and inserts into skin around margin of orbit
- close eyelid gently (involuntary/blinking reflex) by palpebral part
- tighly close eye (voluntary) and wrinkle forehead vertically by orbital part
20
Q
orbicularis oris originates/inserts into/action
A
- originates partially from buccinator/surrounding muscles and from medial mandible/maxilla
- inserts into mucous membrane of lips
- actions are to close and/or protrude the lips
- together with buccinator muscle it keeps food between occlusal surfaces of teeth and not in oral vestibule
- also assists in whilstling and articulation when speaking
- provides gentle resistence which prevents teeth from protruding
21
Q
eyelid function
A
- protect eyeballs from injury and excessive light
- helps keep cornea moist by spreading lacrimal fluid…keeps cornea from drying
22
Q
eyelid if what branches of CNVII are damaged and effect
A
- temporal and zygomatic branches
- eyes cant close
- to prevent eyes drying out eyes must be covered
- surgical intervention if permanent or long-lasting
23
Q
orbicularis oris conists of what muscle fibres
A
- concentric fibres
- arranged arround the orbital margin and eyelids
24
Q
buccinator originates/inserts into/action
A
- originates from posterior part of alveolar process of maxillar/mandible and pterygomandibular raphe
- fibres insert and merge with orbicularis oris
- press the cheeks against molar teeth
- works with tongue to keep food between occlusal surfaces of teeth and out of the oral vestibule
- assist with smiling and resists distension
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pterygomandibular raphe separates which muscles
* buccinator
* superior pharyngeal constrictor
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where does the parotid duct lie/pierce
* lies on top of the masseter
* reaches buccinator and pierces it
* also pierces buccal fat pad
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where does buccal fat pad lie/function/age prominence
* lies superficially to buccinator
* pierces by parotid duct
* much larger in infants
* reinforces infants cheeks and inhibits cheek collapse during feeding
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platysma originates/inserts into/action
* originates from subcutaneous tissue of the infra and supraclavicular regions
* inserts at base of mandible to merge with orbicularis oris, skin of cheek, lower lip and angle of mouth
* tenses the skin of the inferior face/neck
* depress the mandible
* draw corners of mouth inferiorly (grimace)
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muscle of facial expression dilators
* levator labii superioris
* levator anguli oris
* zygomaticus minor
* zygomaticus major
* risorius
* depressor anguli oris
* depressor labii inferioris
30
muscle of facial expression dilators
overall action
* widen mouth
* lift/depress corners of the mouth
31
which muscles elevate and/or evert the upper lip
* levator labii superioris
* zygomaticus muscles
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which muscle results in pout/shows sadness
depressor labii inferioris
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mentalis effect on lower lip
* elevates and protrudes lower lip
* also elevates skin of chin
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muscles used for grin and to depress corner of mouth to convey sadness
* levator anguli oris lifts corner and widens mouoth for grin
* depressor anguli oris acts with risorius to pull down labial commissure to convey sadness
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zygomaticus muscles attach to
zygomatic bone
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what muscles of the nose result in flaring of nostrils
* levator labii superioris alaque nasi
* alar part of nasalis
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what muscles of nose wrinkles skin over dorsum of nose
* procerus
* transverse part of nasalis
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blood supply of face from ICA
* zygomaticofacial artery
* zygomaticotemporal
* supraorbital
* supratrochlear
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blood supply of face from ECA
* facial artery
* buccal, mental and infraorbital which are branches of maxillary artery
* transverse facial which is a branch of superficial temporal
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facial artery path
* from ECA
* cross mandible, buccinator and maxilla
* deep to zygomaticus major and levator labii superiosis
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where can pulses be taken from on face/artery palpated
* facial artery at inferior border of mandible
* transverse facial artery anterior to auricle (below temples)
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venous drainage of face
* facial vein drains most to IJV
* transverse facial vein drains some of upper face
* opthalmic vein drains into cavernous sinus
* retromandibular vein has anterior and posterior part which drains to different locations
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retromandibular vein drainage
* formed by joining of the superficial temporal vein and maxillary vein
* anterior branch unites with facial vein and drains to IJV
* posterior branch gives rise to EJV
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venous drainage
danger triangle of face and why danger
* no valves in external facial veins
* blood flows in both directions
* veins deep to triangle drain to cavernous sinus
* skin infections in this area may spread as intracranial infections
45
muscles of facial expression related to ear/innervated by/blood supply/lymph drainage
* superior, anterior and posterior auricular muscles
* arterial supply is ECA
* venous drainage is to EJV
* lymph drainage is via parotid and mastoid nodes to deep cervical nodes
46
what makes up the eyelid (layers)
* skin
* connective tissue
* muscle (orbicularis oculi)
* orbital septum
* tarsus
* conjunctiva
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eyelid arterial supply/venous/lymph drainage/innervation
* arterial supply via ECA...facial, transverse facial, superficial temporal
* arterial supply via ICA...supratrochlear, supraorbital, lacrimal
* venous drainage is via veins following arteries
* lymph drainage via parotid nodes
* sensory innervation from CNV1 and V2
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what is tarsus
* dense bands of connective tissue
* eyelids supported by tarsi
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where is the parotid region
* anterior to ear
* inferior to zygomatic arch
* between zygomatic arch and lower border of mandibe
* between the SCM, external acoustic meatus and masseter
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parotid gland size/secretions
* largest of salivary glands
* almost entirely serous secretions
* no mucous
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parotid gland is enclosed in
which is
* parotid sheath
* tough fascial capsure
* derived from investing layer of deep cervical fascia
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parotid bed
area occupied by the parotid gland
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why is there lots of fatty tissue between lobes of parotid gland
* as the gland needs to be flexible
* to accomodate movements of the mandible
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parotid duct course
* passes anteriorly and horizontally from parotid gland
* over masseter
* pierces buccinator to enter oral cavity near upper 2nd molar
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arterial blood supply of the parotid gland
* ECA branches supply parotid gland (poor medical students)
* posterior auricular branch
* maxillary artery
* superficial temporal artery
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venous drainage of parotid gland
* maxillary and superficial temporal veins
* these veins join to give the retromandibular vein
* retromandibular vein anterior porion drains to IJV
* posteriorly drains to EJV
70
structures embedded in parotid gland
from superficial to deep
* parotid plexus of facial nerve and its branches
* retromandibular vein
* external carotid artery: post auricular, maxillary and superficial temporal
* also contains parotid lymph nodes
71
parasympathetic innervation of the parotid gland
* comes from parasympathetic component of glossopharyngeal nerve CNIX
* supplies presynaptic secretory fibres to otic ganglion via tympanic nerve and lesser patrosal nerve
* postganglionic fibres pass from otic ganglion to parotid gland via auriculotemporal nerve (CNV3)
72
sympathetic innervation of parotid gland
* from superior cervical ganglion
* and nerve plexus on ECA
* results in vasoconstriction which decreases saliva production and leads to dry mouth
73
CNVII journey through intratemporal portion and roots/branches
* after exiting brainstem at pons CNVII runs through temporal bone
* exits pons as two roots: motor and sensory/parasympathetic
* enters internal acoustic meatus and then facial canal
* roots fuse at facial canal and enlarge to form the geniculate ganglion
* greater petrosal nerve branches off at this point to innervate nasal and lacrimal glands
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before exiting skull CNVII gives off two branches
* nerve to stapedius which supplies stapedius muscles of middle ear
* chorda tympani which travels with lingual nerve to supply taste to anterior 2/3 tongue
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extratemporal portion of CNVII and branches
* exits skull through stylomastoid foramen
* 2 branches given off at beginning
* posterior auricular and digastric
* enters parotid gland and gives off 5 branches
76
posterior auricular nerve supplies
* posterior auricular muscle
* occipital belly of occipitofrontalis
* it is a branch of CNVII
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parotid plexus branches
* 5 branches
* temporal
* zygomatic
* buccal
* marginal mandibular
* cervical
78
what can cause injury to CNVII
* fairly superficial nerve so subject to injury
* cuts
* injury @ birth
* stab/gunshot wounds
* complication of surgery for example parotidectomy
79
lesion of zygomatic branch of CNVII causes
* paralysis and loss of tonus of orbicularis oculi in the inferior eyelid
* causes inferior eyelid to evert (fall away from surface)
* as a result lacrimal fluid is not spread over cornea and leak onto the face
* prevents adequate hydration which makes eye vulteranle to ulceration
* cornea can be damaged or scarred which leads to impaired vision
80
lesion of buccal branch of CNVII causes
* paralysis of buccinator and
* superior part of orbicularis oris and
* upper lip muscles
81
lesion/damage to marginal mandibular branch of CNVII
* paralysis of inferior portion of orbicularis oris and lower lip muscles
* drooping of corners of mouth occurs
* may lead to food and saliva dribbling out of affected side of mouth
* also affects speech as impaired ability to produce labial sounds (B M P W)
* cannot whilstle or blow a wind instrument
82
bells palsy definition/cause/treatment
* facial paralysis when there is no other obvious cause (such as surgical damage or facial laceration)
* viral infections could contribute to onset of inflammation around facial nerve
* treatments include steroids, sometimes anti-virals, eye treatment (tape eye closed) and long-term paralysis may be treated surgically
83
parotid gland tumours and treatment/risks
* often benign however can increase in size and disturb surrounding tisse
* surgery to remove tumour recommended/parotidectomy
* facial nerve injury or bruising is common during procedure
* can cause facial palsy
84
static reconstruction
* tx for facial paralysis considered after 2 years with no improvement
* sling created and is attached to mouth and side of face which prevents the muscles from drooping
* creates facial symmetry at rest
85
great auricular nerve graft uses
* great auricular nerve can be used as a graft for the facial nerve
* if its known that damage to facial nerve will occur during a procedure
* due to close relation of this site during parotidectomy the two procedures can be performed at the same time
* greater auricular nerve is from anterior rami of C2 and C3
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mumps symptoms and cause
* viral infection
* fever, headache, joint pain
* swelling of the parotid gland
* can be painful due to welling being contained within the fibrous sheath of the gland (parotid sheath)
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how is skeletal muscle controlled
* rely on upper and lower motor neurons
* upper motor neuron goes from CNS to spinal cord
* lower motor neuron innervates skeletal muscle
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upper motor neuron location/type of neuron
* cell body in cerebral cortex
* all upper motor neurons are alpha motor neurons
* synapses with LMN in spinal cord
* sometimes synapses with interneuron
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lower motor neuron location/type of neuron
* travels from spinal cord to innervate skeletal muscle
* most are alpha motor neurons
* can also get gamma motor neurons
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how is pyramidal/extrapyramidal tract named
* an enterior surface of medulla pyramid present
* if tract passes through it is pyramidal (direct/voluntary)
* if not it is extrapyramidal (indirect/involuntary)
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types of motor neuron in voluntary/pyramidal tract and function
* alpha motor neuron synapses with anoher alpha motor neuron
* buter upper and lower motor neurons are alpha motor neurons
* alpha motor neurons are directly responsible for initiating contraction of muscle
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extrapyramidal/involuntary tract types of motor neuron
* upper motor neuron is alpha motor neuron
* lower motor neuron can be alpha or gamma motor neuron
* gamma has different function
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gamma motor neuron function
* monitor muscle motor spindle sensitivity
* called readiness potential
* respond to stretch receptors of skeletal muscle to fine-tune muscle contraction
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pyramidal tract function/influenced by
* controls muscle/limb movement
* signal from motor cortex to spinal cord to limb
* influenced by conscious proprioception and extrapuramidal pathway
* influencing signals mostly travel to thalamus then to motor cortex
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extrapyramidal tract function/regions of brain involved
* allows for fluid movements
* involves pons, cerebellum, basal ganglia
* most signals go to thalamus before going to motor cortex to spinal cord to limb
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proprioception function
* gives you a sense of where you are
* where your limbs are
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upper motor neurons leave where from 3 main locations
* leave cerebral cortex from 3 main locations:
* primary motor cortex
* supplementary motor area
* premotor area
* some leave from sensory cortex as well
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how does upper motor neuron travel from cortex to spinal cord
* travels through white mater in brain called corona radiata
* descends through internal capsule and cerebral crus
* cerebral crus is anterior portion of midbrain
* travels through brainstem to spinal cord
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describe upper motor neuron travelling through brainstem
* travels through midbrain and pons
* 85% fibres cross at pyramids in medulla and form the lateral tract
* 15 do not cross and form the anterior tract
* then travels to spinal cord
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motor control at spinal cord
* upper motor neuron and lower motor neuron synapse in ventral horn of spinal cord
* ventral = anterior (grey mater)
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where does anterior/lateral tract of corticospinal tract crossover occur
* anterior corticospinal tract crossing over takes place in spinal cord at segmental level
* lateral corticospinal tract crossing over occurs in medulla in pyramids
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motor control lesion 3 main considerations
1. what side of body will motor deficit be on compared to site of lesion
2. is the lesion on the upper motor neuron or lower motor neuron
3. how much of the body will be affected
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types of paralysis definition
mono, hemi, para, quadra
* monolegia is just one limb
* hemiplegia is arm and leg
* paralegia is both legs
* quadralegia is all limbs
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a lesion affecting corticospinal fibres in the left side of the ventral pons impairs voluntary movement of the arm and lef on which side
* right side
* contralateral as fibres cross at pons
* hemiplegia or paresis
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upper motor neuron lesion signs and symptoms
* decreased speed, accuracy and dexterity
* series of involuntary rapid muscle contraction (clonus)
* period of spinal shock and loss of reflexes
* spastic paralysis/clasp knife response
* no significal muscle atrophy
* overactive bodily reflexes (hyperreflexia)
* hypertonia
* + babinski sign
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spastic paralysis/clasp knife response
* resistence when movement performed by another person
* (increased resistence to passive stretch)
* followed by rapid decrease in resistence
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positive babinski sign
* seen during upper motor neuron lesion
* called extensor plantar response
* toes point up and fanning of toes
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why does hypertonia occur and no significant muscle atrophy not occur during UMN lesion
* hypertonia occurs due to interruption to extrapyramidal tract
* increased activity of gamma motor neurons as LMN still alive which causes high gamma gain
* as LMN supply trophic factors to the muscle no atrophy occurs
116
lower motor neuron lesion signs and symptoms
* flaccid paralysis: muscles become weak and appear limp
* significant atrophy or wasting
* fasciculations: involuntary muscle twitch
* hyporeflexia: decreased or absent reflex responses
* hypotonia: decreased muscle tone, flopiness
* negative babinski sign: toes normal
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main difference between UMN and LMN lesions
* upper lesion causes hypertonia, lower causes hypotonia
* lower there is significant atrophy or wasting of muscle whereas this does not occur during UMN lesion
* positive babinski sign in upper, negative in lower
* hyperreflexia in upper, hyporeflexia in lower
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angle of mandible is where
ramus and body meet
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foramen of mandible and what passes thriugh
* mental foramins provide exit point for mental nerve and associated blood vessels
* mandibular foramen for inferior alveolar nerve and artry/vein
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mandible during development
* in 2 parts
* mandibular symphysis where two parts fuse
* fused part of bone not a suture
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linguala
* at edge of mandibular forman
* protuberance on mandible
* if very large could interfere with IDB
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mylohyoid line clinical relevance
* provides a boundary between oral cavity and floor of mouth
* infections of lower teeth may spread below mylohyoid line to FOM and submandibular triangle
* this causes ludwigs angina
* also important for lower dentures as should stop short of mylohyoid line
* contraction of mylohyoid lifts denture
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smooth spaces superior and inferior to mylohyoid line
* submandibular fossa
* sublingual fossa
* where salivary glands sit
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what type of joint is TMJ/motions
* modified hinge synovial joint
* permits gliding motions, small degree of rotation and elevation/depression
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why is TMJ atypical
* articular surfaces of bone covered by finrocartilage not hyaline cartilage
* hyaline usually covers synovial joints
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what separates TMJ into compartments
* fibrocartilaginous articular disc
* separated the joint into superior and inferior articular cavities
* compartments lined by separate superior and inferior synovial membrane
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why is tmj unstable
* dislocates easily
* more strenghtened posteriorly so anterior dislocations more common
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TMJ ligaments
* 2 extrinsic: sphenomandibular and stylomandibular
* 1 extrinsic: lateral ligament
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sphenomandibular ligament
* extrinsic ligament of TMJ
* runs from spine of sphenoid to linguals
* primary passive support of the mandible
* supports movement of TMJ (acts as fulcrum)
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stylomandibular ligament
* extrinsic ligament of TMJ
* runs from styloid process to angle of mandible
* is a thickening of parotid fibrous capsule
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lateral ligament
* intrinsic ligament of TMJ
* formed by thickened part of joint capsule
* strengthens TMJ laterally and prevents posterior dislocation
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types of TMJ movement
* protrusion
* retraction
* elevation
* depression
* lateral movementz
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how does mandible protrude/retrude
* gliding movements between temporal bone and articular disc
* superior cavity of TMJ
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how is mandible elevated/depressed
* hinge and rotational movements between head of mandible and articular disc
* inferior cavity
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what muscles cause protrusion of TMJ
* mainly lateral pterygoid
* assisted by medial pterygoid
* masseter?
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what muscles cause retraction of TMJ
* mainly posterior, oblique and near horizontal fibres of temporalis
* deep part of masseter
* geniohyoid and digastric
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what muscles cause elevation of mandible
* mainly masseter
* temporalis
* medial pterygoid
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what muscles cause depression of mandible
* lateral pterygoid
* suprahyoid and infrahyoid muscles
* gravity also
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what muscles cause lateral movements of mandible
* temporalis of same side
* pterygoids of opposite side
* masseter
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what happens during anterior dislocation
head of condyle passes anterior to articular tubercules
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causes of anteriog dislocation
* most commonly from sideways blows to chin when mouth is open
* excessive contraction of lateral pterygon during yawning or large bit which makes joing unstable
* may also happen when fracture to the mandible
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when TMJ dislocated mandible remains
* depressed
* lock jaw so unable to close mouth
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why is posterior dislocation of TMJ uncommon
* due to resistence from postglenoid tubercle
* and strong lateral ligament
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what nerves in close proximity to TMJ
* auriculotemporal
* facial nerves
* care taken during surgery
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what can also effect TMJ
* arthritis
* inflamed and abnormal function
* dental occlusion problems and joing clicking (crepitus)
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what are the muscles of mastication and supplied by / derivative of
* temporalis
* masseter
* medial pterygoid
* lateral pterygoid
* supplied by CNV3
* derivatives of 1st pharyngeal arch
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temporalis originates/inserts/innervation/function
* originates from floor of temporal fossa and fascia
* inserts at coronoid process of mandible and anterior border of ramjs near last molar
* innervated by deep temporal nerves from anterior trunk of CNV3
* retracts and elevates mandible and lateral movements of same side
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masster origin/insertion/innervation/function
* originates from maxillary process of zygomatic bone and anterior 2/3 of zygomatic arch
* inserts at angle and lateral surface of ramus
* innervated by masseteric nerve from anterior trunk of CNV3
* elevates the mandible and deep part retracts mandible
* palpable when teeth are clenched
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medial pterygoid origin/insertion/innervation/function
* deep head originates from medial surface of lateral pterygoid plate
* superficial head originates from pyrimidal process of palatine bone
* inserts into medial surface of ramus and angle of mandible
* elevates the mandible, assists with lateral movements, assists with protrusion
* innervated bt nerve to medial pterygoid from main trunk of CNV3
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medial pterygoid IDB
* sometimes needle can pierce medial pterygoid which results in contraction and closes mouth
* patient will have difficulty opening mouth
* called trismus
* usually wears off when muscle heals
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trismus causes
* needle pierces medial pterygoid during IDB
* issues with the TMJ
* due to an infection
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lateral pterygoid origin/insertion/innervation/function
* superior head originates from infratemporal surface of greater wing of sphenoid bone
* inferior head originates from lateral surface of lateral pterygoid plate
* inserts on the front of the neck of mandible:
* superior head to capsule of TMJ and articular disc
* inferior head to pterygoid fovea on neck of mandible
* innervated bt nerve to lateral pterygoid and buccal nerve from anterior trunk of CNV3
* protrudes the mandible, assists with lateral movements and depresses mandible
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temporal fossa boundaries
* superior and posterior borders: superior and inferior temporal lines
* anterior border: frontal process of zygomatic bone and zygomatic process of frontal bone
* inferior border: infratemporal crest
* floor: frontal, parietal temporal and greater wing of sphenoid bone, includes pterion
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roof of temporal fossa formed by
and attachments of this
* roof formed by temporal fascia which is a tough layer of fascia
* attaches to superior temporal line superiorly
* inferiorly splits in two and attaches to lateral and medial surface of zygomatic arch
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temporal fascia function
resistence to masseter muscle
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infratemporal fossa boundaries
* laterally: ramus of mandible
* medially: lateral pterygoid plate
* anteriorly: posterior aspect of maxillar
* posteriorly: tympanic plate, mastoid and styloid process
* superiorly: infratemporal crest of sphenoid bone
* inferiorly: angle of the mandible
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infratemporal fossa muscle contents
* inferior part of temporalis
* lateral pterygoid
* medial pterigoid
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infratemporal fossa blood vessles
* maxillary artery
* pterygoid venous plexus
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infratemporal fossa nerves
* mandibular nerve CNV3
* inferior alveolar nerve
* lingual nerve
* buccal nerve
* otic ganglion
* chorda tympani
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anterior division of CNV3 main branches
* several motor branches to muscles of mastication
* masseteric nerve
* deep temporal nerves
* nerve to lateral pterygoid
* gives off branches before becoming the buccal nerve
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posterior division of CNV3 main branches
* inferior alveolar nerve
* lingual nerve
* auriculotemporal nerve
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chorda tympani function
* carry sensory fibres conveying taste from anterior 2/3 tongue
* carries secretomotor fibres to submandibular and sublingual salivary glands
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pterygomandibular space
* part of infratemporal fossa between medial pterygoid and mandible
* clinical term
* region filled in part by fat and by pterygoid venous plexus
* here is where anaesthetic injected for IDB
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where is anaesthetic injected for IDB
pterygomandibular space
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mandibular nerve arises from/exits
* arises from trigeminal ganglion in middle cranial fossa
* carries motor root and sensory root
* exits through foramen ovale into infratemporal fossa
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what is on mandibular nerve just inferior to foramen ovale and on medial side of CNV3
otic ganglion
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auriculotemporal nerve journey and function
* branch of CNV3
* encircles middle meningeal artery
* gives off many branches
* largest branches supply sensory fibres to auricle and temporal region
* sends sensory fibres to TMJ
* innervates parotid gland: passes postsynaptic secretomotor fibres from otic ganglion
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inferior alveolar nerve jouney and function
* branch of CNV3 posterior trunk
* enters mandibular foramen and passes through mandibular canal
* forms dental plexus to supply mandibular teeth
* mental nerve passes through mental foramen to supply skin of lower lip and chin, gingiva of mandibular incisors
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lingual nerve journey and function
* branch of CNV3
* passes medial and inferior to mandibular 3rd molar
* joined by chorda tympani within infratemporal fossa
* sensory to anterior 2/3 tongue, floor of mouth, lingual gingivae
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maxillary artery main branches
* middle meningeal artery (1st part)
* inferior alveolar artery (1st part)
* anterior and posterior deep temporal arteries (2nd part)
* masseteric artery (2nd part)
* buccal artery (2nd part)
* superior alveolar artery (3rd part)
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parts of maxillary artery
* 1st part: mandibular (deep to neck of mandible between lateral and medial pterygoid)
* 2nd part: pterygoid (superficial or deep to lateral pterygoid)
* 3rd part: pterygopalatine (passes into pterygopalatine fossa)
* based on relation to lateral pterygoid muscle
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middle meningeal artery distribution/supply
* supplies dura mater, periosteum, bone, red bone marrow, calvaria, trigeminal ganglion
* arises medial to neck of mandible from 1st part of maxillary artery
* enters middle cranial fossa through foramen spinosum
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inferior alveolar artery distribution/supply
* branches off first part of maxillary artery (mandibular part)
* enters mandibular foramen with IAN
* supplies teeth of lower jaw via dental branches
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masseteric artery distribution/supply
* branches off 2nd part (pterygoid part) of maxillary artery
* passes laterally through the mandibular notch to enter deep surface of masseter muscle
* supplies masseter
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anterior and posterior deep temporal arteries distribution/supply
* branch off 2nd part of maxillary artery
* pass superiroly across roof of infratemporal fossa
* enters deep surface of temporalis muscle
* supplies temporalis
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buccal artery distribution/supply
* branches off 2nd part of maxillary artery
* passes anteriorly onto buccinator muscle
* supplies cheek, buccinator and buccal oral mucosa
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superior alveolar artery distribution/supply
* branch off 3rd part of maxillary artery
* supply the maxillary teeth, adjacent mucosa and gingivae
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pterygoid venous plexus location
* between temporalis and pterygoid muscles
* most veins that accompany maxillary artery drain into this plexus
* communicating branches with both facial vein and cavernous sinus (via emissary veins)
* can lead to spread of infection
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what is corticobulbar tract & function
* pathway that controls voluntary movement of skeletal muscles of the head and neck
* two neuron pathway involving upper motor neuron and lower motor neuron (cranial nerve)
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where does upper motor neuron of corticobulbar tract come from
* primary motor cortex lateral surface (face and hands on lateral surface)
* primary sensory cortex
* pre-motor cortex
* supplementary motor area
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summarised pathway of corticobulbar tract
1. upper motor neuron from cortex (4 areas) most from primary cortex
2. goes through region of white mater called corona radiata
3. travels through genu of internal capsule (in between thalamus and basal ganglia)
4. makes its way to motor nucleus in brainstem
5. synapse with lowor motor neuron (cranial nerve)
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what is internal capsule and differences between corticobulbar and corticospinal tract
* channel of white matter in between thalamus and basal ganglia
* has an anterior limb, genu and posterior limb
* corticobulbar tract goes though genu
* corticospinal tract goes through posterior limb
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all cranial lower motor neurons are what? which CN is the exception
* all lower motor neurons aka CN are ipsilateral except CNIV
* trochlear nerve is contralateral so crosses over to supply other side
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corticobulbar tract
common innervation
* upper motor neuron synapses bilaterally at motor nuclei (both sides of midbrain)
* lower motor neuron aka cranial nerve is unilateral (innervates same side as site of motor nuclei)
* example is occulomotor nerve CNIII
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CNV motor nucleus is in
and pathway summary
* motor nucelus in pons
* UMN bilateral to nucleus
* LMN ipsilateral
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nucleus ambiguus
* shared motor nucelus from CNIX and CNX
* UMN is bilateral
* LMN ipsilateral
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which innervation from UMN is more dominant on cotricobulbar tract
* contralateral innervation from UMN more dominant
* if damage to contralateral innervation it has backup innervation
* no paralysis but can cause muscle weakness/inability to control movements (pseudobulbopalsy)
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golden rules of corticobulbar tract
1. the UMN in the pathway is a supranuclear fibre (another word for UMN of corticobulbar tract)
2. corticobulbar tract is travelling close to corticospinal tract (common for lesion to affect both tracts)
3. each upper motor neuron connects bilaterally to a cranial nerve (except CNVII and CNIX)
4. the lower motor neuron in the pathway WILL be a cranial nerve
5. cranial nerve cell bodies innervated by UMNs will have a motor function
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exceptions to the golden rules of corticobulbar tract
* CNVII to lower face and CNXII to tongue
* CNVII has two motor nuclei (upper and lower motor nucleus on each side)
* hypoglossal nerve only has contralateral UMN
* CNIV is only lower motor neuron to be contralateral (all other CN are ipsilateral)
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lesion to UMN of corticobulbar tract with common innervation
* will not produce facial paralysis of muscles of the face and head
* due to bilateral UMN innervation
* instead mild forms of weakness occur in affected muscles
* called pseudobulbarpalsy
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facial nerve corticobulbar tract
innervation description
* unique as motor nucleus splits into upper and lower motor nucleus
* upper motor nucleus recieves bilateral innervation and synapses with CNVII to supply upper half of face (ipsilateral)
* lower portion of motor nucleus recieves contralateral innervation only so UMN cross over
* LMN of lower portion of motor nucleus is ipsilateral
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facial nerve corticobulbar tract
what happens if lesion of UMN
* upper part of face recieves bilateral innervation to upper portion of motor nucleus so still functions due to backup innervation
* lower part of face has no backup = no innervation to contralateral side
* lesion of R side of UMN so symptoms on left side of lower face: dropping of mouth, asymmetry of lower face
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facial nerve corticobulbar tract
what happens if lesion of LMN
* all facial muscles will be paralysed
* on ipsilateral side of the face
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hypoglossal nerve corticobulbar tract
what happens if lesion of UMN
* upper motor neuron is contralateral only
* lesion of UMN on L side means right LMN does not recieve innervation
* this mean for example right side of genioglossus doesnt work
* tongue deviates to right side on protrusion as no resistence from R side of genioglossus
* = deviation of tongue uppon protrusion to the contralateral side
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hypoglossal nerve corticobulbar tract
what happens if lesion of LMN
* LMN is ipsilateral
* so deviation of tongue to the same (ipsilateral) side upon protrusion
* this is becase the muscle on this side recieves no innervation so no resistence on this side so musle from other side pushes tongue
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What does this diagram show
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What does this diagram show
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What does this diagram show
