Head Flashcards
1
Q
What is the bony orbit?
A
Pyramidal cavity made of 7 bones - maxillary, frontal, ethmoid, sphenoid, lacrimal and palatine)
2
Q
What does the bony orbit contain?
A
Orbit
Lacrimal gland
Optic foramina - Optic N CN2, opthalmic A (ICA)
SOF - CN3, CN4, CN5, CN6 and middle meningeal contribution to opthalmic A (variantion)
IOF - infraorbital N, infraorbital A, inferior opthalmic V
3
Q
What are the foramina of the orbit?
A
Contains the 3 foramina,
Optic foramen, inferior orbital fissure, superior orbital fissure
Apex of the pyramid is the optic foramen
4
Q
What is the gross anatomy of the bony orbit?
A
Superiorly:
Frontal bone, sphenoid (lesser wing)
Medially:
maxilla, lacrimal bone, ethmoid, sphenoid (lesser wing)
palatine
Inferiorly:
maxilla, zygomatic (laterally), palatine
Laterally:
zygomatic, greater wing of sphenoid
Foramina - superior orbital fissure, inferior orbital fissure, optic foramina
5
Q
What is the arterial supply of the orbit?
A
opthalmic A (C6 of ICA)
6
Q
What is the venous drainage of the orbit?
A
superior opthalmic v (drains to cavernous sinus)
inferior opthalmic v (drains to cavernous sinus)
7
Q
What is the nerve supply of the orbit?
A
Cn2 Cn6
Supraorbital N V1
Infraorbital N V2
8
Q
What lives in the superior orbital fissure?
A
Lazy french…
Lacrimal
Frontal
Trochlear
Superior division of oculomotor
Nasocilliary
Inferior division of oculomotor
Abducens
Superior opthalmic V
Middle meningeal artery contribution to opthalmic
9
Q
What lives in the inferior orbital fissure?
A
infraorbital n
infraorbital A
inferior opthalmic vein
10
Q
What are the internal carotid artery and external carotid artery anastomoses?
A
Petrous ICA + Maxillary Artery = Vidian A
Cavernous ICA anastomoses with ECA = inferolateral trunk (through foramen ovale, spinosum, rotundum)
Opthalmic A anastomoses with accessory middle meningeal artery (through foramen ovale)
Opthalmic A anastomoses with middle meningeal artery (through superior orbital fissure) = recurrent meningeal A
Opthalmic A anastomoses with facial A (via angular A)
Opthalmic A anastomoses with superficial temporal A (via zygomaticoorbital A)
Rete mirable anastomoses with ECA - middle meningeal A - ACA / MCA rete mirable
Little’s area in nose - sphenopalatine A from maxillary (ECA), anterior ethmoidal A (ICA)
11
Q
What are the carotid vertebrobasilar anastomoses?
A
Persistent primitive trigeminal A
Persistent primitive otic A
Persistent primitive hypoglossal A
Persistent primitive proatlantal A
12
Q
What are the meninges and the meningeal spaces?
A
3 layers of tissue which surround the brain
Dura, arachnoid, pia
Extradural space - between cranium and outer layer of dura
Subdural space - between inner layer of dura and arachnoid mater
Subarachnoid space - between the arachnoid mater and pia mater
13
Q
What is the dura mater?
A
Tough 2 layered membrane
Outer dura is periosteal
Inner dura is meningeal
2 dural layers are closely adherent, except where they split around the dural venous sinuses to make inwards projections.
falx cerebri
tentorium cerebelli
diagphram sellae
14
Q
What is the arachnoid mater?
A
It is the membrane contacting the dura
Seperated from the pia mater via CSF
Connective tissue bands join the pia and the arachnoid mater - the arachnoid trabeculae
15
Q
What is the pia mater?
A
Single cell membrane
Contains blood vessels which supply the brain
Invaginates into sulci
16
Q
What do the meninges contain?
A
Their arterial supply + veins + nerves
Arachnoid granulations - CSF desorption
17
Q
What is the arterial supply of the meninges?
A
The middle meningeal A (which is a branch of the maxillary A which goes through the foramen spinosum) and accessory meningeal A.
In the cavernous sinus, meningeal branches of carotid A
18
Q
What is the venous drainage of the meninges?
A
The venous sinuses
19
Q
What is the lymphatic drainage of the meninges?
A
No lymphatics - this is the function of the subarachnoid space
20
Q
What is the nerve supply of the meninges?
A
Opthalmic N (V1 of trigeminal N)
In posterior fossa - uses CN 9 + 10
In foramen magnum - uses CN1 + 3
21
Q
What is the anatomical variation associated with the meninges?
A
Tentorium cerebelli duplication
22
Q
What is the function of the nasolacrimal apparatus?
A
To allow for drainage of the tears of the eye
23
Q
What is the gross anatomy and tear drainage pathway?
A
lacrimal gland
to the upper fornix
absorbed by nasal canaliculi
drain to lacrimal sac
nasolacrimal duct
inferior nasal meatus
24
Q
Where do the specific parts of the nasolacrimal apparatus sit?
A
Lacrimal gland
- superolateral to orbit
- lateral to leveator palpebrae
Lacrimal canaliculi
- medial margin of upper and lower eyelid
Lacrimal Sac
- lateral to ethmoid air cells
- grooves the medial orbit
Nasolacrimal duct
- lateral to nasal turbinates
- empties into inferior nasal meatus
25
What is the arterial supply of the nasolacrimal apparatus?
The lacrimal A
Which is a branch of opthalmic A (C6)
26
What is the venous drainage of the nasolacrimal apparatus?
superior opthalmic vein - drains to cavernous sinus
27
What is the lymphatic drainage of the nasolacrimal apparatus?
superficial parotid lymph nodes
28
What is the nerve supply of the nasolacrimal apparatus?
Lacrimal N (from V1)
29
What is the optic N?
It is CN2.
Communication between the globe and the calcarine sulcus.
30
What is the gross anatomy of the optic nerve?
Pre chiasma - has 4 parts
intraocular, intraorbital, intracanalicular, intracranial
Then goes to the optic chiasm
Lateral Genucleate Nucleus
Optic radiation
Calcarine sulcus
31
What is the relevance of the optic N and meninges?
Optic nerve is covered in meninges as it is a cranial N.
It can therefore grow a meningioma
And this is why intracerebral pressure rises can lead to papilloedema.
32
What runs with the optic N?
Central retinal A (this is the first branch of the opthalmic A C6)
Runs with the opthalmic A in the topic canal. However note optic N is superior
33
What is the course of the 4 pre chiasmal parts of the optic nerve?
Intraocular - begins at optic disc
Intraorbital - optic N in intraconal space
Intracanalicular - runs through optic canal
Intracranial - from optic canal to chiasm
34
What happens with the optic N at the optic chiasm -> tract -> optic radiation?
Optic N nasal fibres decussate
Temporal fibres do not
Then becomes optic tract, to lateral genuicleate nucleus of thalamus + superior colliculus
Then becomes optic radiation -Then to calcarine sulcus of occipital cortex
35
What are the relations of the optic N?
The opthalmic A, is inferior to the optic canal
then crosses to become superior in the intraorbital part
central retinal A - first branch of opthalmic A, will run in the center of the intraorbital optic N and supplies the retina
36
What is the arterial supply of the optic N?
Opthalmic A in the optic canal C6, which is inferior to optic N
central retinal A (first branch of opthalmic)
which will run with infraorbital part of optic N
37
What are the anatomical variations of the optic N?
Can indent sphenoid sinus, go around sphenoid sinus or go through!
38
What is the function of the opthalmic artery?
It is the arterial supply of the orbit.
Comes from the internal carotid A. C6.
has extensive anastomoses with the External carotid A
39
What are the anastomosing branches involved with the opthalmic A and the external carotid A?
Middle meningeal
accessory meningeal
facial
superficial temporal branches
40
What is the origin of the opthalmic artery?
Is medial to the anterior clinoid.
comes off the internal carotid A.
Runs into the optic canal inferolateral to the optic N
and then crosses superiorly over the optic N in the conal space.
41
How does the opthalmic A terminate?
Via multiple anastomoses with the external carotid artery
facial A (via angular A)
superficial temporal A (via zygomatic orbital A)
middle meningeal A
accessory meningeal A
42
What does the opthalmic A supply?
orbital contents
retina
43
What are the branches of the opthalmic A?
central retinal A
lacrimal A
anterior ethmoidal A (superolateral nasal cavity)
posterior ethmoidal A (superolateral nasal cavity)
frontal A (supratrochlear)
44
What is the venous drainage corresponding to the opthalmic A?
superior opthalmic V
inferior opthalmic V
45
What are the anatomical variations associated with the opthalmic A?
Opthalmic A communicates with middle meningeal A
Recurrent meningeal A (present when there is lots of anastomoses between the opthalmic A + MMA)
Opthalmic A regression, with MMA to supply orbit
46
What are the radiological spaces of the orbit?
The globe
Subdivided into the anterior and posterior chambers by the lens
Optic nerve sheath complex
Optic N
Opthalmic A
Central retinal A
Central retinal V
surrounding meninges
Intraconal space
Cranial N 2,3,4,V1, 6
Fat
Opthalmic A
Superior opthalmic vein
Conal space
extra ocular muscles: medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique, inferior oblique
Extraconal space
fat
lacrimal gland
lacrimal sac
47
What are the paranasal sinuses?
air filled spaces in the cranium around the nose
48
What is the function of the paranasal sinuses?
Lined with mucus - produce about 1L of mucus a day, propel mucus through the nasopharynx
all except the sphenoid sinus will empty into the middle meatus. The sphenoid empties into the superior meatus
49
What is the gross anatomy of the paranasal sinuses?
4 PAIRED sinuses - named for the bones they reside in
Frontal sinus
- drains via ostiomeatal complex, to middle meatus
Ethmoid sinus
- drains via ostiomeatal complex, to middle meatus
Maxillary sinus
- drains via ostiomeatal complex, to middle meatus
Sphenoid sinus
- drains via sphenoethmoidal recess, to superior meatus
50
What is the osteomeatal complex?
Common channel which drains the frontal, anterior / ethmoid, maxillary sinuses to the middle meatus
51
What is the function of the osteomeatal complex?
allows passage of airflow and mucocillary drainage to middle meatus
5 STRUCTURES
maxillary ostium, infundibulum, ethmoidal bulla, uncinated process, hiatus semilunaris
52
What is the gross anatomy of the osteomeatal complex?
maxillary ostium
- drain maxillary sinus
infundibulum
- common channel! drains the maxillary ostium + ethmoid sinus to hiatus semilunaris
uncinate process
- hook like process, comes off posteronasal lacrimal duct, forms the anterior border of the hiatus semilunaris
ethmoid bulla
-one single ethmoid air cell that projects over the top of the hiatus semilunaris
hiatus semilunaris
- final drainage passage/pathway
-between ethmoid bulla + uncinated process
-empties in the middle meatus
53
What is the course of air through the osteomeatal complex?
maxillary ostium, influndibulum, hiatus semilunaris, middle meatus
54
What are the relations of the osteomeatal complex?
superiorly - ethmoid sinus
laterally - maxillary sinus
55
What are the anatomical variants associated with the osteomeatal complex?
infraorbital / haller cell
agger nasi cell
uncinated process bullae
uncinated process deviation
concha bullosa
intralamellar cell
nasal septum deviation
56
What is ethmoid sinus?
Bony labryinth of air cells in the ethmoid bone
drains into osteomeatal complex to middle meatus
57
Where does the ethmoid sinus sit?
Between medial wall of orbit, and lateral wall of upper nasal cavity
58
What is the gross anatomy of ethmoid sinus?
Bony labriynth
- infraorbital air cells / haller cells
- agger nasi cells
- sphenoethmoidal cells / onodi cells
- ethmoidal bulla
59
What is the contents of the ethmoid sinus?
Mucus producing
60
What are the anatomical variations associated with the ethmoid sinus?
infraorbital / haller cells
agger nasi cells
sphenoethmoidal air cells / onodi cells
Ethmoidal bulla
61
What is the sphenoid sinus?
Paired cavity in the sphenoid body
Pneumatisation starts at 2 years of age
empties into the sphenoethmoidal recess of superior meatus
62
Where does the sphenoid sinus sit?
sits anterior and inferior to the sella
in the body of the sphenoid bone
63
What are the relations of the sphenoid sinus?
Superior: Internal carotid A
Optic N
Lateral: Cavernous sinus
Inferior: nasopharynx
Superoposterior: sella
64
What is the arterial supply of the sphenoid sinus?
internal carotid artery
65
What are the anatomical variants associated with the sphenoid sinus?
Main one is associated with the optic Nerve - can run through it, around it, anterior to it, adjacent to it
Onoidi/sphenoethmoidal cell -
66
What is the infratemporal fossa?
The infratemporal fossa is the masticator space. It will sit lateral and and posterior to the maxillary sinus.
continuous superiorly with the temporal fossa + sits lateral to the pharynx (superior constrictor, tensor levator. palate)
67
What does the infratemporal fossa contain?
ptyergoid muscles
branches of maxillary A
mandibular division of the trigeminal N
68
What is the gross anatomy of the infratemporal fossa?
Roof
========
greater wing of sphenoid - foramen ovale: accessory meningeal A
foramen spinosum: middle meningeal A
is continuous with the temporal fossa
Floor
==========
medial ptyergoid
medial
=============
lateral ptyergoid
pharynx - superior constrictor/tensor palati/ levator palati
lateral
=========
ramus of mandible
anterior
===========
maxillary sinus
posterior
=============
carotid sheath
superior
===========
temporal fossa
69
What are the contents of the infratemporal fossa?
medial and lateral ptyergoid
temporalis tendon
branches of the maxillary artery - accessory meningeal A + middle meningeal A
ptyergoid venous plexus
mandibular division of the trigeminal N (lingual N, inferior alveolar N)
70
What are the important relations for the infratemporal fossa?
continuous with middle cranial fossa - through foramen ovale + foramen spinosum (for acc meningeal A + middle meningeal A)
continous with the temporal fossa superiorly which transmits tendon of temporalis
71
What is the mandible?
Bone which articulates with the cranium - via TMJ
72
What is the function of the mandible?
holds the inferior alveolar border + 16 teeth
Involved in mastication
73
What is the osteology + structure of the mandible?
Two halves which fuse at midline symphysis menti
Body - contains a mandibular canal - with the inferior alveolar A + N
Angle - divides body from ramus
Ramus - covered by parotid
coronoid process - for temporalis
condylar process - articulates with TMJ
74
What are the main joints associated with the mandible?
TMJ - synovial joint
between the condylar process of mandible + temporal bone
75
What are the ligaments associated with the mandible?
Sphenomandibular ligament
Lateral temporamandibular ligament
76
What is the arterial supply for the mandible?
inferior alveolar A
(from maxillary)W
77
WHat is the nerve supply of the mandible?
inferior alveolar N
from V3 (mandibular division of trigeminal N)
78
What are the relations of the mandible?
BETWEEN ramus of mandible + sphenomandibular ligament = maxillary A
ramus is covered by the parotid
79
What is the temporomandibular joint?
articulates the mandible with the temporal bone
80
What is the function of the temporomandibular joint?
mastication
81
What is the articulating surfaces involved in temporomandibular joint?
temporomandibular. joint
- mandible - condylar process
- temporal bone: temporomandibular fossa, articular tubercle
82
What type of joint is the temporomandibular joint?
synovial
83
What are the ligaments involved with the temporomandibular joint?
sphenomandibular ligament
temporomandibular ligament
** maxillary artery runs between the sphenomandibular ligament and the ramus of the mandible
84
What are the muscles involved with the temporomandibular joint?
lateral ptyergoid
-only muscle to open mouth
temporalis
-attaches to coronoid process: powerful
Gives origin to the floor of the mouth via mylohyoid
85
What are the fat/menisci/ fascia involved with the temporomandibular joint?
temporomandibular disc
- anterior band
- posterior band
- thin zone in the middle
86
What is the arterial supply of the temporomandibular joint?
maxillary artery + its branches
87
What is the nerve supply of the temporomandibular joint?
V3 mandibular N from the trigeminal N
-> auriculotemporal N
88
What are the relations of the temporomandibular joint?
anterior: lateral ptyergoid
posterior: parotid gland, auriculotemporal N, external acoustic meatus
superior: middle cranial fossa
inferior: maxillary artery, middle meningeal A
89
What is the maxillary artery?
It is one of the larger and terminal branches of the external carotid artery
Divided with relations to the lateral ptyergoid,
*MANDIBULAR
*PTYERGOID
*PTYERGOPALATINE
supplies the deep structures of the face and also involved with ECA - ICA anastomoses
90
What is the origin of the maxillary artery?
comes off as the larger and anterior branch of the carotid
Courses anteriorly through the parotid and terminates as the sphenopalatine artery (in the ptyergopalatine fossa)
91
What does the maxillary artery supply?
Upper and lower jaws
muscles of mastication
palate
nose
meninges
92
What are the branches of the maxillary artery?
First - mandibular part
=====================
Middle meningeal A
Accessory meningeal A
Auriculotemporal A
Deep auricular A
Anterior tympanic A
Second - ptyergoid part
====================
Masseteric A
Buccinator A
Branches to ptyergoids
anterior deep temporal A
posterior deep temporal A
Third - ptyergopalatine part
==========================
Infraorbital A
Greater palatine A
Posterior superior alveolar A
Pharyngeal A
Sphenopalatine A (termination)
93
What are the ICA - ECA anastomoses involving the maxillary A?
maxillary A - cavernous ICA (inferolateral trunk)
maxillary A - petrous ICA (vidian A)
Maxillary A - opthalmic ICA (middle meningeal A)
94
What is the arterial supply to the nose?
Extensive anastomoses between the ECA - ICA in littles area.
Sphenopalatine A
Greater palatine A
Anterior + Posterior ethmoidal A
Superior labial branch of the facial A
95
What is the arterial supply with regards to the gross anatomy of the nasal cavity?
Anterior
===============
superior labial branch of facial A
Anterior ethmoidal A
Greater palatine A (contains littles area/kesselbach plexus)
Inferior
==============
greater palatine A
superior labial branch of facial A
Posterior
==============
Sphenopalatine A
Posterior ethmoidal A
Superior
===========
Anterior ethmoidal A
Posterior ethmoidal A
Medial
===========
Sphenopalatine A
Anterior ethmoidal A
Lateral
==========
Sphenopalatine A
superior labial branch of facial A
96
What is involved in little's area?
anterior ethmoid A
Sphenopalatine A
Greater palatine A
superior labial branch of facial A
site of 90 percent of epistaxis
anterior - inferiorly in nasal septum
ICA - ECA anastomosis
97
What is the purpose of the nasal cavity?
To warm and humidify the air
Common drainage pathway for the paranasal sinuses
98
What is the gross anatomy of the nasal cavity?
Laterally
- superior concha
- middle concha
- lateral concha
medially (cartilage and bones)
- vomer (posteriorly)
- midline septum
- perpendicular plate of ethmoid bone
99
What are the contents of the nasal cavity?
Superior meatus - sphenoethmoidal recess
Middle meatus - emptying of osteomeatal complex
inferior meatus - emptying of nasolacrimal duct
100
What are the relations to the nasal cavity?
Linked to the paranasal sinuses
Linked to the eustachian tube - posterior
101
What is the venous drainage of the nasal cavity?
Facial - IJV
superior and inferior opthalmic veins - pytergoid + cavernous plexus
102
What is the lymphatic drainage of the nasal cavity?
lateral pharyngeal nodes / deep cervical chain
103
What is the nerve supply of the nasal cavity?
Olfatory N
Greater + lesser palatine nerves
pytergopalatine ganglion
104
What is the anatomical variation of the nasal cavity?
Concha bullosa and intralamellar air cells, Deviated nasal septum
105
What is the middle ear?
Contains the ossicles
Sits between the tympanic membrane and the lateral wall of the tympanic cavity (inner ear)
106
What is the purpose of the middle ear?
To transmit sound from vibrating tympanic membrane to cochlea oval window
107
What are the different parts of the middle ear?
Epitympanum:
- prussak's space is most inferolateral attic. medial to malleus head
- roof of epitympanum, is tegmen tympani
- aditus and antrum
Mesotympanum
Hypotympanum
Retrotympanum
Ossicles - malleus, incus, stapes
Muscles - stapedius
tensor tympani
108
What are the relations to the middle ear?
anterior- carotid wall
posterior - retrotympanum, CN7 mastoid segment
superior - middle cranial fossa + tegmen tympani
lateral: tympanic membrane
medial: tympanic segment CN7, cochlear/oval window
109
What is the arterial supply of the middle ear?
cardiotympanic A + deep auricular A
110
What are the nerves supply to the middle ear?
CN7 - stapedius
V3 - nerve to tensor tympani
111
What is the muscles / fascia / ligaments for the middle ear?
stabilising ligament, attached to malleus
112
What are the anatomical variants associated with the middle ear?
Aberrant ICA
- can get a retrotympanic pulsatile mass
due to petrous ICA going posterolaterally
113
What are the ossicles of the ear?
bones of the ear involved in sound transmission
transmit and mechanically amplify sound from the tympanic membrane to the oval window of cochlea
114
What is the gross anatomy of the middle ear ossicles?
Malleus
- Head, neck, manubrium
- the bottom of the manubrium is the UMBO
- tensor tympani will attach to the manubrium
Incus
- Body
- Short process
- Long process
- Lenticular process
Stapes
- head is stapedius
- crura/arch
- footplate
115
What is the course of the ossicles?
Tympanic membrane - manibrium of malleus ->
Head of malleus / body of incus ->
lenticular process of incus / head of stapes ->
footplate of stapes / oval window
116
What is the relations of the ossicles?
malleus menubrium will articulate with the tympanic membrane
Head of malleus will articulate with body of incus
Lenticular process of incus articulates with head of stapes
Footplate of stapes articulates with oval window of cochlea
Between the scutum and head of malleus is PRUSSAKS space
117
What is the arterial supply of the ossicles?
Cardiotympanic (Petrous ICA C2)
118
What are the nerves supply of the ossicles?
CN7 stapedius
V3 N to tensor tympani
119
What are the muscles and ligaments associated with the ossicles?
stapedius - stapes relates to CN7
Tensor tympani, attaches to menubrium of malleus, related to CN V3
120
What does the inner ear contain?
Structure responsible for hearing (saccule / cochlear) and utricle (balance)
121
Where does the inner ear sit?
In the petrous temporal bone
122
What is the gross anatomy of the inner ear?
It is a bony labrinyth
Contains the membranous labriynth. surrounded by perilymph
123
What does the inner ear contain?
The cochlea, vestibule, semicircular canals.
124
What is the gross anatomy of the cochlea?
Cochlea has 2 and a half turns
cochlear N to modiolus
contains cochlear duct
125
What does the vestibule contain?
Utricle + saccule
Vestibular N
126
What is the gross anatomy of the semicircular canals?
lateral
posterior
superior
3 semicircular ducts
127
What does the inner ear contain?
A membranous labryinth
128
What are the relations to the inner ear?
Anterior: middle cranial fossa, genucleate ganglion
Posterior: internal acoustic meatus
Superior: labrynithine portion CN7 between cochlea + vestibule
Inferior: tympanic part of C7
Medial: petrous apex
Lateral: middle ear
129
What is the arterial supply of the inner ear?
Labryinthine artery (from basilar A, goes through internal acoustic meatus with CN7 + 8)
anterior tympanic A (from maxillary/ mandibular portion)
130
What is the lymphatic drainage of the inner ear?
Bony and membranous labryinths seperated by perilymph
131
What is the nerve supply to the inner ear?
Vestibulocochlear N
- vestibular division goes to vestibule
- cochlear division goes to modiolus (anterior)
Facial N is a key relation
132
What are the anatomical variants associated with the inner ear?
Aberrant ICA
Absence of cochlear N ( part of deafness workup in MRI )
labryinthine A can be from AICA or basilar A
133
What is the temporal bone?
It is the bone which demarcates the posterior and middle cranial fossa
2 processes, 2 meatuses, 4 parts
134
What is the function of the temporal bone?
Contains the middle ear and inner ear.
135
What is the osteology / structure of the temporal bone?
Squamous part
- lateral wall of middle cranial fossa
Petrous part
- contains inner ear
Mastoid part
- contains air cells
Tympanic part
- forms bony cavity of external auditory canal
Styloid process
- Attachments for stylohyoid, stylopharyngeus, styloglossus
zygomatic process
- articulates with the zygomatic process of maxilla
136
What is the contents of the temporal bone?
external auditory canal
middle ear - ossicles, epitympanum, mesotypanum, hypotympanum, retrotympanum
inner ear - bony labrytinth - cochlea, vestibule, semicircular canals
internal acoustic meatus - CN7 + 8, labrythintine artery
137
What is involved with the temporal bone?
internal carotid A (petrous part)
facial N - internal acoustic meatus, labrynthine, tympanic, mastoid segments
138
What are the relations to the temporal bone?
anterior: sphenoid
posterior: occipital
superior: parietal bone
inferior: styloid process ( and muscles - stylohyoid, stylopharyngeus, styloglossus)
lateral: ear and temporalis muscle
medial: internal acoustic meatus and basissphenoid
139
What is the origin of the facial N?
The pontomedullary junction
140
What is the course of the facial N?
Intracranial segment
begins at the pondomedullary junction
Internal acoustic meatus / cisternal segment
then goes to the internal acoustic meatus / cisternal segment (in an anterosuperior configuration to CN8)
Labryinthine segment
courses superior to and between the cochlear + vestibule, terminates at genucleate ganglion / anterior genu
Tympanic segment
runs backwards, inferior to semicircular canal, superior to oval window, to posterior genu
Mastoid segment
runs behind retrotympanic space, to stylomastoid foramen
Extracranial
exits stylomastoid foramen
runs lateral to external carotid and styloid process
141
Where does the facial N terminate?
temporal
zygomatic
buccal
marginal mandibular
cervical
142
What are the branches of the facial N?
chorda tympani (anterior 2/3 taste of tongue, lingual N)
greater superficial petrosal N - lacrimal gland
N to stapedius (sound dampening)
nervus intermedius - contributions to glands, submandibular, sublingual, lacrimal
terminations - temporal, zygomatic, buccal, marginal mandibular, cervical
143
What does the facial nerve supply?
Muscles of facial expression
Nerve to stapedius
Taste to anterior 2/3 of tongue
Glands - sublingual, submandibular, lacrimal
144
What does the arterial supply of the facial N?
labryinthine A - very fragile
145
What is the trigeminal N?
Fifth cranial N
Has 3x key branches
It is responsible for motor and sensory function - sensory to the face and head, and motor to muscles of mastication
only mandibular division carries motor fibres
146
Where does the trigeminal ganglion sit?
Sits in meckels cave
Posterolateral to the cavernous sinus
Motor nuclei from the pons
Sensory nuclei from the tegmentum - extends to midbrain - through pons + medulla - to cervical cord
147
What is the course of the trigeminal nerve?
The course of the trigeminal N
Starts in the pons from the motor nuclei, sensory from the tegmentum of the midbrain to spinal cord
Goes to pre pontine cistern, from ventrolateral pons, through porous trigeminus and enters meckel's cave
148
Where does the trigeminal nerve terminate?
Meckel's cave - contains trigeminal ganglion
Sits posterolateral to cavernous sinus
Divides into opthalmic, maxillary, mandibular branches
149
What are the branches of the trigeminal N?
V1-opthalmic
V2- maxillary
V3-mandibular
150
What is the course of V1 opthalmic division of the trigeminal N?
Through the lateral wall of the cavernous sinus
Terminates at the superior orbital fissure
151
What are the branches of V1 the opthalmic division of the trigeminal N?
frontal N
nasociliary N
lacrimal N
frontal N
supraorbital N
152
What does V1 supply?
Supplies the sensation to the upper 1/3 of the face
Afferent corneal reflex
153
What is the course of the maxillary division of the trigeminal N?
course is through the lateral wall of the cavernous sinus
Terminates at the foramen rotundum into ptyergopalatine fossa (inferior orbital fissure superiorly)
154
What are the branches of the maxillary division of the trigeminal N?
The infraorbital N
155
What does the maxillary division of the trigeminal N supply?
Sensation to middle 1/3 of face
156
What does the mandibular division of the trigeminal N supply?
muscles of mastication
sensation to lower 1/3 of face
TMJ
157
What is the course of the mandibular division of the trigeminal N?
through FORAMEN OVALE, not cavernous sinus
Terminates at the foramen ovale
158
What are the branches of the mandibular division of the trigeminal N?
inferior alveolar N
auriculotemporal N
lingual N
motor branches to muscles of mastication
159
What is the parotid gland?
It is the largest salivary gland
intimately related to ECA, facial N, retromandibular vein
160
What is the function of the parotid gland?
Secretes saliva, amylase into oral cavity via the parotid duct.
161
What is significant about the parotid gland?
Facial nerve will course over it and divide into its terminal branches
parotid duct will leave anteriorly over the masseter
162
What are the contents of the parotid duct?
facial N
retromandibular vein
external carotid A
163
What is the course of the parotid duct?
runs from anterior parotid, runs over masseter, plunges through buccinator, and empties into upper 2nd molar
164
What are the relations of the parotid gland?
Anterior:
masseter, parotid duct
Posterior:
mastoid process of temporal bone
sternocleidomastoid
Medial: parapharyngeal space, styloid process, carotid space
Lateral: subcutaenous tissue
Superior: zygomatic process
Inferior: angle of mandible, external carotid artery
165
What is the arterial supply of the parotid gland?
External carotid artery - which runs through it -
divides into maxillary A + superficial temporal A in parotid
166
What is the venous drainage of the parotid gland?
Retromandibular V
167
What is the nerve supply of the parotid gland?
auriculotemporal N (V3)
facial N courses through the parotid
168
What is the lymphatic drainage of the parotid gland?
parotid lymph nodes - drain to the deep cervical chain
169
What are the muscles / ligaments / fascia involved with the parotid gland?
Parotid fascia
170
What is the anatomical variation associated with the parotid gland?
Accessory parotid duct
171
What is the jugular venous system?
Main drainage of the head + neck
IJV is major venous return for the cranial cavity
EJV is for the face + neck
172
What is the origin of the internal jugular vein?
Inferior petrosal sinus + sigmoid sinus - which creates the jugular bulb
This is inferior to the jugular foramen
173
What is the course of the internal jugular vein?
Courses out of the jugular foramen, with the spinal accessory nerve and vagus nerve
Continues down in the carotid sheath, with the internal carotid artery + vagus nerve
Is deep to sternocleidomastoid (access to the internal jugular vein is between the two heads of SCM and inferiorly)
Joined by the common trunk of the facial/lingual/submandibular
174
What is the termination of the internal jugular vein?
Joins the subclavian vein to terminate as the brachiocephalic trunk
175
What is the origin of the external jugular vein?
The union of the retromandibular vein + posterior auricular vein
176
What is the course of the external jugular vein?
Runs inferiorly through the neck, superficial to sternocleidomastoid
SCM is the landmark which divides the IJV + EJV
177
What is the termination of the external jugular vein?
empties into the subclavian vein
178
What are the tributaries to the external jugular vein?
retromandibular + posterior auricular vein
anterior jugular vein
179
Where is the ptyergopalatine fossa?
Anterior to the maxillary bone
Posterior to the ptyergoid process
Inferior to inferior border of orbital fissure
Medially is the sphenopalatine foramen (where the sphenopalatine incisures of the palatine bone meet the sphenoid bone)
MAJOR SITE OF DISTRIBUTION OF MAXILLARY NERVE + MAXILLARY ARTERY
180
What are the boundaries of the ptyergopalatine fossa?
Anterior:
Posterior part of maxillary bone
Posterior:
Ptyergoid plate of sphenoid bone
Medial:
Palatine bone
Lateral:
Ptyergomaxillary fissure
Superior:
Inferior orbital fissure
Inferior:
Palatine canal
181
What are the contents of the ptyergopalatine fossa?
ptyergopalatine part of the maxillary artery
ptyergopalatine ganglion
maxillary division of trigeminal N (via foramen rotundum)
nerve to ptyergoid canal
182
What are the communcations with the ptyergopalatine fossa?
ANTERIORLY: Inferior orbital fissure - connects to the orbit
POSTERIORLY: vidian canal connects to middle cranial fossa
SUPERIORLY: foramen rotundum connects to cavernous sinus
INFERIORLY: Palatine canal connects to palate
MEDIALLY: sphenopalatine foramen with sphenopalatine artery connects to the nasal cavity
LATERALLY: ptyergomaxillary fissure connects to masticator space, middle temporal fossa
183
What are the cranial vault variants?
Persistent metopic suture
Foramen ovale / spinosum asymmetry
Arachnoid granulations (look like punched-out lesions)
Jugular foramen asymmetry
Hyperostosis frontalis interna
Persistent mendosal
