B6-091 Head Anatomy Flashcards
5 layers of scalp
Skin
Connective tissue (dense)
Aponeurotic layer
Loose connective tissue
Pericranium
why does a scalp wound bleed profusely?
the dense connective tissue holds the arteries open
what layers are considered the scalp when someone has been scalped?
skin
dense connective tissue
aponeurotic layer
allows scalp movement and also provides a potential space for infection
loose connective tissue layer
aponeurosis of the scalp comes from which muscle?
occipital frontalis
**causes gaping wound
what causes a scalp injury to be a gaping wound?
cut is through aponeurosis and the
occipital frontalis pulls down on it
the anterior cranial fossa houses the […] lobe
frontal
the middle cranial fossa houses the […] lobe
temporal
the posterior cranial fossa houses the […] lobe
cerebellum and bainstem
what nerve passes through the cribriform formina?
CN1 olfactory
what nerve passes through the optic canal?
CN2 optic
what nerve passes through the superior orbital fissure? [4]
CN 3 occulomotor
CN 4 trochlear
CN 5-1 ophthalmic of trigeminal
CN 6 abducens
what nerve passes through the foramen rotundum?
CN 5-2 maxillary of trigeminal
what nerve passes through the foramen ovale?
CN 5-3 mandibular of trigeminal
what nerve passes through the internal acoustic meatus? [2]
CN 7 facial
CN 8 vestibulocochlear
what nerve passes through the jugular foramen? [3]
CN 9 glossopharyngeal
CN 10 vagus
CN 11 spinal accessory
what nerve passes through the hypoglossal canal?
CN12 hypoglossal
middle meningeal artery passes through foramen […]
spinosum
brainstem passes through foramen […]
magnum
optic nerve and […] pass through optic canals
ophthalamic arteries (supply orbit)
[…] and accessory meningeal artery pass through foramen ovale
mandibular nerve
interior pertrosal, sigmoid sinuses, and ascending pharygeal/occipital arteries pass through […] foramen
jugular
provide a route for infection to go between the scalp and dural venous sinuses
emissary veins
anosmia indicates damage to
CN 1 (olfactory)
cerebrospinal fluid rhinorrhea indicates damage to
CN1 olfactory
loss of pupillary constriction indicates damage to
CN 2 optic
visual field defects indicates damage to
CN 2 optic
dilated pupil
lost pupillary reflex on side of lesion
indicates damage to
CN3 occulomotor
ptosis
eye turns “down and out”
indicates damage to
CN3 occulomotor
inability to look down when eye is adducted indicates damage to
CN 4 trochlear
loss of pain and touch over cheek indicates damage to
CN5 trigeminal
deviation of mandible to side of lesion when mouth is opened indicates damage to
CN5 trigeminal
temporalis and masseter muscles do not contract indicating damage to
CN 5 trigeminal
eye fails to move laterally
diplopia on lateral gaze
indicates damage to
CN 6 abducens
paralysis of facial muscles (eye remains open, angle of mouth drops, forehead doesnt wrinkle)
indicated damage to
CN 7 facial
progressive unilateral hearing loss
tinnitus
indicates damage to
CN 8 vestibulocochlear
loss of taste on posterior third of tongue
loss of sensation on affected side of palate
indicates damage to
CN 9 glossopharyneal
sagging of soft palate, deviation of uvula to one side, hoarseness
indicates damage to
CN 10 vagus
paralysis of SCM and trapezius causing drooping of the shoulder indicates damage to
CN 11 spinal accessory
protruded tongue deviates toward affected side indicates damage to
CN 12 hypoglossal
“dipping in” of the anterior fontanel indicates
dehydration of infant
anterior fontanelle typically fuses by […]
18 months
bulging of anterior fontanel indicates
increased ICP
posterior fontanel usually fuses by
end of 1st year
fontanelles located deep to temporalis [2]
sphenoidal
mastoid
3 layers of meninges
dura mater
arachnoid mater
pia mater
protrudes through meningeal layer of dura into venous sinuses and spinal cord
arachoid mater
what meninge is adherent to the brain and highly vascularized?
pia mater
2 layers of dura mater
periosteal layer
meningeal layer
the space between the arachnoid mater and pia mater contains
CSF
dural sheath that separates the right and left hemispheres of brain
falx cerebri
dural sheath that separates the occipital lobe from cerebellum
tentorium cerebelli
dural sheath that separates the two hemispheres of the cerebellum
falx cerebellum
dural sheath that covers the pituitary gland
diaphragma sellae
eventually the dural sinuses lead to the
internal jugular vein
sinus that extends from superior orbital fissure, runs along either side of the stella tursica to petras bone
cavernous dural sinus
cavernous sinus has direct communication with the
ophthalmic vein (has direct communication with facial vein)
how can zits cause infection of the cavernous sinus?
valveless veins with direct communication between facial and ophthalmic veins
the region where the frontal, parietal, temporal, and sphenoid bones join
pterion
a blow to the side of the head can cause a fracture of the pterion, damaging what artery?
middle meningeal artery
what nerves supply innervation to the anterior fossa? [2]
CN V1-opthalmic
CN V2-maxillary
what nerve supplies innervation to the middle fossa?
CN V3, mandibular
tentorium cerebelli is innervated by
CN1 olfactory
**tumor pressing here can cause headaches behind eyes
what nerve supplies innervation to posterior fossa?
C2 and C3 but carried by Hypoglossal and Vagus
the […] produces CSF
choroid plexus
describe the flow of CSF
lateral ventricle -> foramen of monroe -> third ventricle -> cerebral aqueduct -> 4th ventricle -> subarachnoid space
CSF is returned to blood stream via
subarachnoid granulations and villi
CSF drains primarily into the […] sinus
superior sagittal
true space that contains CSF, arteries of Circle of Willis, and veins
subarachnoid space
potential space between cranium and periosteal dura
epidural
potential space between dura and arachnoid
subdural
fracture of middle meningeal artery at pterion would result in […] hematoma
epidural
lens shaped deficit on CT imaging
epidural hematoma
crescent shaped deficit on CT imaging
subdural hematoma
blood leaking into ventricles on CT imaging
subarachnoid hematoma
falls or lumbar punctures can tear the […] causing a subdural hematoma
cerebral veins
a subarachnoid hematoma results from tearing what vessels?
vessels in circle of willis
what structures run through the parotid gland? [3]
CN 7 (facial)
retromandibular vein
external carotid artery
a tumor of the parotid gland can cause
facial paralysis (compression of CN 7)
muscle going around eye
orbicularis oculi
muscle going around mouth
orbicularis oris
what muscle keeps the cheeks taut when chewing so food doesn’t fall out?
buccinator
muscle that helps you smile
zygomaticus major
muscle that helps you frown
compressor anguli oris
muscles of mastication [2]
masseter
temporalis
branches of external carotid artery in face [3]
facial
superficial temporal
transverse facial
branches of internal carotid artery [2]
supraorbital
supratrochlear
facial artery terminates as
angular artery (at the eye)
what branches of facial a. supply the lips?
superior and inferior labial (anastomose with each other)
artery that lies anterior to the ear, enabling you to take a pulse there
superficial temporal
superficial temporal a. anastomoses with
supraorbital
facial a. anastomoses with
supratrochlear a.
exits the skull via the internal acoustic meatus
runs in facial canal
exits via stylomastoid foramen
facial nerve CN7
provides motor innervation to muscles of facial expression
CN 7 facial
provides parasympathetic innervation to lacrimal, nasal, and palatine glands
and submandibular/sublingual salivary glands
CN 7 facial
provides taste to anterior 2/3 of tongue
CN 7 facial via chorda tympani
provides sensation to external acoustic meatus
CN 7 facial
provides motor innervation to muscles of mastication
CN V3- mandibular
passes through the cavernous sinus and enters the orbit via the superior orbital fissure
V1-ophthalmic
passes through the cavernous sinus and exits the skull via foramen rotundum
V2 maxillary
exits the skull via the foramen ovale
V3 mandibular
provides sensation from cornea, skin of forehead, scalp, upper eyelid, and part of nasal cavity
V1 ophthalmic
provides sensation from the skin of face, lower eyelid, cheek, upper lid, maxillary teeth, mucosa of nose, maxillary sinus
V2 maxillary
sensation from skin of mandible, lower lip, side of head, mandibular teeth, TMJ joint, anterior 2/3 of tongue
V3 mandibular
4 paranasal sinuses
frontal
ethmoid
sphenoid
maxillary
all of the sinuses are innervated by
CN 5
inflammation of the mucous membranes of paranasal sinuses
sinusitis
maxillary and frontal sinuses develop first followed by
ethmoid, sphenoid
why is it unlikely for a young child to have sinusitis?
sinuses develop later in life
provides blood supply to frontal sinus
anterior ethmoid a.
aperture of the frontal sinus
frontonasal duct into middle meatus
nerve that supplies the frontal sinus
supraorbital via V1
structures superior to the sphenoid
hypophyseal fossa (pituitary)
optic chiasm
provides blood supply to sphenoid sinus
pharyngeal arteries from maxillary
nerves that supply the sphenoid sinus [2]
posterior ethmoid via V1
orbital branches via V2
first sinus to develop
maxillary
aperture of maxillary sinus
middle meatus
nerves that supply maxillary sinus
infraorbital and alveolar branches of V2
provides blood supply to maxillary sinus
infraorbital and superior alveolar a. from maxillary
apertures of ethmoid sinus [3]
middle meatus
ethmoid bulla
superior meatus
chronic bacterial infections in the ethmoid air cells can erode into the
orbit
provides blood supply to ethmoid
anterior and posterior ethmoid
nerve that supplies ethmoid
anterior and posterior ethmoids via V1 and nasal branches from V2
if bacterial rhinosinusitis goes into the cranial fossa, it can cause
intracranial abscess
meningitis
if a bacterial infection breeches the sphenoid laterally it can cause
septic carvernous sinus thrombosis
(cranial nerve palsies with or without fever)
posterior ethmoid air cells open into the […] meatus
superior
the middle ethmoid air cells open into the […]
ethmoid bulla of middle meatus
the frontal sinus, anterior ethmoid sinus, and maxillary sinus open into the
semilunar hiatus
the nasolacrimal duct opens into the […] meatus
inferior
why do we get so much maxillary sinus pain during sinusitis?
opening to maxillary sinus is superior –> hard for mucus to drain
nasal mucosa become swollen/inflamed during URTIs or allergic reactions
rhinitis
what is this image showing?
septal deviation
brings a lot of blood from the maxillary artery causing posterior nosebleeds
sphenopalatine a.
anastomosis in anterior nasal cavity prone to anterior nosebleeds
Kesselbachs
veins originating from the maxillary drain to
pterygoid plexus
veins originating from ophthalmic drain to
cavernous sinus
veins originating from facial drain into
facial v.
what is the significance of the triangle of danger?
consists of superior ophthalmic vein, facial vein, pterygoid plexus, and cavernous sinus
an infection in this area will go straight to the cavernous sinus
major nerve that innervates the nasal septum
nasal palatine
what layer of the scalp contains sweat/sebaceous glands and hair follicles?
skin
what layer of the scalp is richly vascularized and contains the cutaneous nerves?
dense connective tissue
broad, strong tendinous sheath that covers the calvaria and serves as the attachment site for the occipitofrontalis muscle
aponeurosis
sponge-like layer of scalp including potential spaces that can distend with fluid as a result of injury or infections
loose connective tissue
forms the external periosteum of the neurocranium
pericranium
[…] and […] pass through the foramen ovale
mandibular division of trigeminal
accessory meningeal artery
what cranial nerves pass through the superior orbital fissure?
3, occulomotor
4, trochlear
V1, ophthalmic
6, abducens
opthalmic veins pass through the […] fissure
superior orbital
what nerves pass through the internal acoustic meatus? [2]
facial nerve CN7
vestibulocochlear CN 8
the spinal accessory will enter the skull through […] and exit through […]
enter via foramen magnum
exit via jugular foramen
what nerves exit via the jugular foramen? [3]
CN 9 glossopharyngeal
CN 10 vagus
CN 11 spinal accessory
the mandibular division of trigeminal and the accessory meningeal artery travel through
foramen ovale
pterion is formed by the fusion of [4]
frontal
parietal
temporal
sphenoid
fusion of the anterior fontanelle will form […] between the front and parietal bones
bregma
fusion of the posterior fontanelle will form […] between the occipital and parietal bones
lambda
what artery lies in the cavernous sinus?
internal carotid
the posterior aspect of tentorium cerebelli is innervated by
ophthalmic division of trigeminal
[…] innervates a portion of the dura in the anterior cranial fossa and part of the anterior wall of the middle cranial fossa
CN V2-maxillary
[…] innervates dura on the lateral wall of the anterior cranial fossa and middle cranial fossa
mandibular
[…] will innervate the dura of the posterior cranial fossa
C1 and C2 carried by hypoglossal or vagus
space that contains CSF and the circle of Willis
subarachnoid
rupture of the middle meningeal artery will cause bleeding in the […] space
epidural
rupture of the arteries of the Circle of Willis will bleed into the […] space
subarachnoid
rupture of the cerebral veins will cause bleeding in the […] space
subdural
structures that can be damaged when removing parotid gland tumors [3]
facial nerve
retromandibular vein
external carotid artery
supplies the anterior 2/3 of the tongue with general sensation
lingual (from trigeminal)
supplies anterior 2/3 of tongue with taste
chorda tympani (from facial CN 7)
frontal sinus drains into the […] meatus via the frontonasal duct
middle meatus
the sphenoid sinus drains into the
sphenoethmoid recess
the maxillary sinus will drain into the […] meatus
middle
the anterior ethmoid air cells will drain into the […] meatus
middle
the middle ethmoid air cells will drain into the […] meatus
middle
the posterior ethmoid air cells will drain into the […] meatus
superior
the roof of the sphenoid is located inferior to the
hypophyseal fossa and pituitary gland
erosion of the lateral wall of the sphenoid sinus will lead to the
cavernous sinus
the […] sinus is located inferior to the orbit and superior to the molar teeth
maxillary
the maxillary sinus is located inferior to […] and superior to […]
orbit
molar teeth
nasolacrimal duct drains into the […] meatus
inferior
the lateral nasal branches supply the
lateral walls of the nasal cavity
infection from the nasal cavity can spread to […] sinus
cavernous
the nose can drain via the […] into the cavernous sinus
pterygoid plexus
the superior and inferior ophthalmic veins drain into the
cavernous sinus
why does the scalp bleed so profusely?
the dense connective tissue holds the lumen of the arteries open
why is a circular dressing used for head wounds?
blood vessels run inferior to superior
compresses both inferior and superior
how can a head wound cause black eyes?
the fascial sheet is continuous from forehead to zygomatic arch, so bleeding in the loose connective tissue will allow it to pool in the periorbital area
when would a head wound require stitches?
if it goes through to aponeurosis it will gape, requiring closure
why is infection a primary concern of a head wound?
infection can spread from loose connective tissue via emissary veins into dural venous sinuses
**can cause thrombosis, meningitis
the nerves of the head run what direction?
inferior to superior
**important to facial surgery, will use U shaped flaps to preserve the neurovascular structures
what two nerves run in the internal acoustic meatus?
facial nerve- CN7
vestibulocochlear- CN 8
weakness or paralysis of ipsilateral muscles of facial expression indicates lesion in
facial CN 7
**issues smiling, puckering lips, closing one eye lid
supplies taste to anterior 2/3 of tongue
facial CN 7 via chorda tympani
supplies general sensation to anterior 2/3 of tongue
lingual via trigeminal (V3)
reduced/lack of tear production indicates a lesion in
facial CN7
provides parasympthetic innervation to sublingual and submandibular glands
facial CN 7 via chora tympani
tinnitus/ringing/hearing loss in ears indicates lesion in
vestibulocochlear- CN 8
vertigo/dizziness/nausea and vomiting can indicate a lesion in
vestibulocochlear- CN 8
the parasympathetic innervation of CN 7 (facial) travels via […] to the lacrimal gland
greater petrosal
hyperacoutistic sound may indicate a lesion to
CN7-facial to stapedius
CN7 branches through the geniculate ganglion and runs downs the [….] to supply sensory and motor innervation to the face
facial canal
a lesion in CN 7 at the facial canal would leave what functions unaffected?
tear production
maybe stapedius
lens shaped deficit on CT
epidural hematoma
what vessel is the source of the bleed in epidural hematoma?
middle meningeal a.
what foramen does the middle meningeal a. run through?
foramen spinosum
**middle cranial cavity
between the skull and the periosteal layer of the dura
epidural space
a blow to the side of the head can damage what structure?
pterion
what bones fuse to form pterion?
frontal
parietal
temporal
sphenoid
cresent shaped deficit on CT
subdural hematoma
what vessel is the source of the bleed in subdural hematoma?
cerebral veins
what space do subarachnoid hematomas form in?
subarachnoid
subarachnoid space contains
CSF
what vessel lies in close approximation to pterion?
middle meningeal a.
what can cause teeth pain in maxillary sinus infection?
pain travels maxillary nerve–>infraorbital nerve –> middle superior alveolar and anterior superior alveolar nerves
what is superior to the maxillary sinus?
orbital floor
what is inferior to the maxillary sinus?
teeth/oral cavity
where is the aperture of the maxillary sinus?
semilunar hiatus of the middle meatus
when you cry, why does your nose run?
tears run from lacrimal duct to inferior meatus out nose
what 5 arteries make up Kesselbach’s plexus?
sphenal palantine
greater palantine
anterior ethmoidal
posterior ethmoidal
septal branch from labial
what causes spurting of blood from the nose in a anterior nose bleed?
Kesselbachs plexus
what artery causes a posterior nose bleed?
sphenopalantine
**usually needs to be ligated
what causes obstruction of the nasal airway? [2]
septal deviation
cartilage/nasal bone displacement
if a nasal fracture extends into the cranium, what happens?
CSF rhinorrhea
what nerve goes through the cribiform plate?
olfactory
halo or target sign indicates
CSF mixed with blood
symptoms of septic cavernous thrombosis
orbital edema and swelling
CN palsies effecting eye pattern
fever
AMS
how does infection spread to the cavernous sinus?
ophthalmic vein –> cavernous sinus
facial vein –> pterygoid plexus of veins –> cavernous sinus
due to valveless veins in this area
loss of abducens nerve may be an indication of aneurysm in
internal carotid artery
**run in close proximity
large opening that connects posterior cranial fossa with the exterior base of the skull
jugular foramen
what three nerves lie in the interior jugular foramen?
glossopharyngeal IX
vagus X
spinal accesory XI
the posterior compartment of the jugular foramen contains the
internal jugular vein
originates at the terminal end of the sigmoid dural sinus
internal jugular
connects the middle cranial fossa with the exterior base of the skull
foramen ovale
transmits the mandibular division of the trigeminal nerve and small accessory meningeal artery
foramen ovale
conveys the middle meningeal artery from the infratemporal fossa into the cranium
foramen spinosum
large opening that connect the floor of the middle cranial fossa with the exterior base of the skull
foramen lacerum
transmits the greater petrosal nerve to the pterygoid canal
foramen lacerum
large, oblique passage running through the base of the skull
carotid canal
the carotid canal merges with the […] to bring the internal carotid to the sella tursica
foramen lacerum
identify A-E
A. foramen ovale
B. foramen spinosum
C. foramen lacerum
D. carotid canal
E. jugular foramen
supplies general sensation to the skin of the lower lip, chin, cheek, anterior auricle, and lateral scalp
mandibular division of trigeminal V3
supplies innervation to the mandibular teeth and gingivae via the inferior alveolar nerve
mandibular division of tigeminal V3
supplies sensory to skin of upper eyelid, anterior aspect of the nose, forehead, and anterior scalp
opthalmic division of trigeminal V1
supplies sensory to the skin of the lower eyelid, cheek, upper lips, upper dentition/gingivae, maxillary sinus, and lateral nose
maxillary division of trigeminal V2
supplies motor to the buccinator muscle and muscles of upper lip
buccal branch of facial n.
no sensory
supplies motor to the muscles of the lower lip/chin
marginal mandibular of facial n.
no sensory
most likely layer for shear injury of scalp
loose connective tissue
external scalp layer containing sweat/sebaceous glands and hair follicles
skin
layer of scalp that is richly vascularized and contains cutaneous nerves
dense connective tissue
layer of scalp that is a broad tendinous sheath covering the calvaria
serves as an attachment for muscle bellies of occipitofrontalis
aponeurosis
sponge-like layer of the scalp that includes potential spaces that may distend as the result of injury/infection
loose connective tissue
opens into the superior nasal meatus
posterior ethmoidal sinus
open into the semilunar hiatus in the middle meatus [3]
maxillary
frontal
anterior ethmoid
drain into the ethmoid bulla in the middle nasal meatus
middle ethmoidal
rupture of the […] causes epidural hemorrhage
middle meningeal
rupture of […] causes subarachnoid hemorrhage
circle of willis arteries
rupture of […] causes subdural hematoma
cerebral veins
cranial dural sinuses normally contain
venous blood
parallels the course of the internal carotid within the cavernous sinus
abduces CN6
most likely to be damaged as a result of internal carotid aneurysm in the cavernous sinus
CN 6 abducens nerve
lies in the hypophyseal fossa of the sella tursica of the sphenoid
pituitary gland
lies immediately posterior and superior to the sphenoid sinus
pituitary gland
lies in the maxilla lateral to the wall of the nasal cavity
maxillary sinus
sinus that lies between the orbit and nasal cavity
ethmoid air cells
pain from an anterior nosebleed would be sensed by
nasopalatine n
septal branch of ethmoidal
innervate the lateral walls of the nasal cavity [2]
anterior ethmoid
lateral nasal nerves
vessels that form Kiesselback plexus
anterior and posterior ethmoidal arteries
sphenopalatine artery
greater palatine artery
septal branch of superior labial
ipsilateral paralysis of the face (bells palsy) indicates at lesion where?
internal acoustic meatus (facial n.)
a lesion in the facial nerve at the level of the facial canal would result in
ipsilateral facial paralysis
decreased saliva from submandibular and sublingual glands
lack of taste on ipsilateral 2/3 of anterior tongue
hyperacusis d/t lack of stapedius
decreased sensation to ear
a lesion in facial nerve at the parotid gland would result in
ipsilateral facial paralysis
a lesion in facial nerve at the stylomastoid foramen would result in
ipsilateral facial paralysis
reduced sensation to ear
nerves that pass through the superior orbital fissure [4]
oculomotor III
trochlear IV
V1 opthalmic
abducent VI
