Transcript 02. Face

Skin innervation of the face
Skin of the face is supplied by
branches of trigeminal nerve except the
area over the angle of mandible &
parotid gland, which is supplied by
great auricular nerve..
Ophthalmic nerve supplies the region
developed from the frontonasal process.
The maxillary nerve supplies the
region developed from the maxillary
process of 1st pharyngeal arch.
The mandibular nerve supplies the
region developed from the mandibular
process of 1st pharyngeal arch.
Skin of face has numerous sweat &
sebaceous glands. It is connected to
underlying bones by loose C.T, in which
are embedded the muscles of facial
expression.
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No deep fascia is present in the face.
Ophthalmic
Nerve
It supplies skin of forehead,
upper eyelid, conjunctiva, & side of the
nose, it has 5 branches :
1-Lacrimal N. : supplies skin &
conjunctiva of lateral part of upper eyelid.
2-Supraorbital N.: winds at supraorbital
notch,it supplies skin & conjunctiva on the
central part of upper eyelid + skin of
forehead.
3-Supratrochlear N. : it lies medial to
supraorbital N. it supplies skin &
conjunctiva on medial part of upper eyelid
+ skin of forehead.
4-Infratrochlear N. : leaves orbit to
supply skin & conjunctiva on the medial
part of upper eyelid + skin of adjoining
part of the side of the nose.
5-External nasal N. : leaves nose to
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supply skin on the side of the nose down
as far as the tip.
Maxillary Nerve
It supplies the skin of posterior part of
the side of nose, lower eyelid, cheek,
upper lip, lateral side of the orbit.
It has 3 branches :
1-Infraorbital N. : is a direct
continuation of maxillary N. it leveas orbit
via infraorbital foramen. It gives
numerous small branches to supply skin
of lower eyelid & cheek, side of nose, &
the upper lip.
2-Zygomaticofacial N. : passes onto
face via a small foramen on lateral side of
zygomatic bone to supply skin over the
cheek.
3-Zygomaticotemporal N. : passes
through a small foramen on the posterior
part of zygomatic bone to supply skin of
temple.
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Mandibular Nerve
It supplies skin of lower lip, lower part
of face, temporal region & part of the
auricle + side of scalp. It has 3 branches
1-Mental N. : emerges from the mental
foramen of mandible to supply skin of
lower lip & chin.
2-Buccal N. : enters the face from
under cover of the masseter. It passes
over the buccinator. It supplies skin &
m.m of cheek.
3-Auriculotemporal N. : leaves
upper border of parotid gland , between
superficial temporal vessels & auricle to
supply skin of auricle, external auditory
meatus, outer surface of tympanic
membrane & skin of scalp above auricle.
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Arterial Supply of the Face
Facial artery : arises from external
carotid artery.
-it reaches face by piercing deep fascia at
the lower border of the mandible and then
curving up to the face close to anteroior
border of masseter, here its pulse can be
easily felt.
-it then passes upwards in a tortuous
course over the mandible and buccinator
towards the angle of mouth.
-it then ascends along side of nose to the
medial angle of eye, where it
anastomoses with the terminal branches
of the ophthalmic artery.
Superficial temporal artery : the
smaller terminal branch of external carotid
artery within the parotid gland.It ascends
in front of auricle to supply the scalp.
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Arterial Supply of the Face
Transverse facial artery : a branch of
superficial temporal artery of external carotid
artery, within the parotid gland.It runs forward
across the cheek just above parotid duct.
Infraorbital artery : it is the terminal part of
maxillary artery (one of terminal branches of
external carotisd artery), it enters face via
infraorbital foramen.
Mental artery : branch of inferior alveolar
from maxillary from ext.c.artery, ,it enters face
via mental foramen of mandible.
Zygomaticofacial & zygomaticotemporal
arteries, from superficial temporal artery.
Lacrimal artery : from ophthalmic artery, of
internal carotid artery.
Supraorbital & Supratrochlear arteries
: branches of ophthalmic artery, of internal
carotid artery , supply skin of forehead.
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Branches of Facial artery
1- Submental artery : arises at the
lower border of the body of mandible
to supply skin of chin + lowe lip.
2- Inferior labial artery : arises near
angle of mouth to run medially in the
lower lip and anastomoses with its
fellow of opposite side.
3- Superior labial artery : runs
medially in the upper lip and gives
branches to the septum + ala of nose.
4- Lateral nasal artery : supplies skin
on the side & dorsum of nose.
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Venous Drainage of Face
Facial vein :
-is formed at the medial angle of eye
by union of supraorbital &
supratrochlear veins.
-it is connected to cavernous sinus
through superior ophthalmic vein.
This connection is of great clinical
importance because it provides a
pathway for spread of infection from
face to cavernous sinus.
-It descends behind the facial artery to
the lower border of body of mandible.
-It crosses with the facial artery
superficial to submandibular gland.
–It is joined by anterior division of
retromandibular vein to form common
facial vein to end into the internal
jugular vein.
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Tributaries of Facial vein
It recevies tributaries that
correspond to the branches of
facial artery.
It is joined to pterygoid venous
plexus ( a venous network lying
around pterygoid muscles) by deep
facial vein and to the cavernous
sinus by superior ophthalmic
vein.
Transverse facial vein joins
superficial temporal vein within the
parotid gland.
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Lymph Drainage of the Face
Lymph from forehead + anterior
part of face drains into submandibular
L.Ns., a few buccal lymph nodes may
be present along course of these
lymph vessels.
Lateral part of face + lateral parts
of eyelids drin into parotid L.Ns.
Lower lip + chin are drained into
submental L.Ns.
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Facial Nerve
It emerges from stylomastoid
foramen to enter the parotid gland , it
supplies all muscles of facial
expression. it does not supply the
skin ,It runs within substance of
parotid gland, it divides into 5
terminal branches :
1- Temporal branch : emerges from
upper border of gland to supply
anterior + superior auricular
muscles, frontal belly of
occipitofrontalis, orbicularis oculi and
corrugator supercillii.
2- Zygomatic branch : emerges
from anterior border of parotid gland
to supply orbicularis oculi.
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Facial Nerve
3- Buccal branch : emerges from
anterior border of parotid gland
below parotid duct to supply
buccinator +ms.of upper lip & nostril.
4- Mandibular branch : emerges
from anterior border of parotid gland
to supply ms. of lower lip.
5- Cervical branch : emerges from
lower border of parotid gland , it
descends in the neck to supply
platysma muscle + depressor anguli
oris muscle.
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Skin & Fascia of the Face
• Skin of face has numerous sweat &
sebaceous glands.
• It is connected to the underlying bones
by loose connective tissue (superficial
fascia), in which are embedded muscles
of facial expression.
• No deep fascia in the face.
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Muscles of Face
(muscles of
facial expression)
They are called ms. Of
expression because they pull skin
of face to produce various
expressions.
They are arranged in groups
around the eye, nose & mouth.
They have bony origin.
They are inserted into skin of
face (no deep fascia in face).
They are supplied by branches
of facial N., Except levator P.S. by
occulomotor N. (striated ms.) +15
sympathetic N. (smooth ms.).
Muscles of Face
A) Muscles of eyelids :
1- levator palpebrae
superioris (the dilator ms. of
eyelids, lying in the orbital
cavity).
2-Orbicularis oculi (the
sphincter ms of eyelids).
3-Corrugator supercilii
(deep to orbicularis oculi).
4-Occipitofrontalis (ms. of
scalp).
B) Muscles of Nose :
1-Procerus.
2-Compressor & dilator
naris.
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Muscles of C)
Face
Muscles of Lips :
Sphincter muscle of the lips :
“ Orbicularis Oris”.
Dilator muscles of the lips :
1-Levator labii superioris
alaeque nasi.
2-Levator labii superioris.
3-Depressor labii inferioris.
4-Zygomaticus minor.
5-Zygomaticus major.
6-Levator anguli Oris (deep to
zygomatic ms.).
7-Depressor anguli Oris.
8-Risorius.
9-Mentalis.
D) Muscles of Cheek
:
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“Buccinator”
Muscles of Face
(muscles of
facial expression)
3 large muscles :
1- Buccinator m. (ms. of cheek).
2- Orbicularis oculi m.
3- Orbicularis oris m.
Many small muscles :
1- Dilator ms. of lips
(separate lips) :
-Levator labii superioris alaeque nasi,
levator labii superioris.
-Zygomaticus minor & major.
-Levator anguli oris, risorius &
depressor anguli oris.
-Depressor labii inferioris & mentalis.
origin : bones & fascia around oral
aperature.
Insertion : into substance of lips.18
2- Corrugator supercilli :
-It lies deep to orbicularis oculi. origin :
superciliary arch (bone).
Insertion : skin of eyebrow.
Action : vertical wrinkles of forehead, as
in frowning.
3- Compressor naris & dilator
naris :
origin : maxilla. Insertion : the fibres
are continuous with those of opposite
side in front of the bridge of nose to
form aponeurosis of bridge of nose.
Action : compesses & widens nasal
cartilages and aperature.
4- Procerus :
- It is continuous with the medial part of
occipito-frontalis ms.
Origin : nasal bone.
Insertion : medial part of skin of
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eyebrow. Action : wrinkles skin of nose.
Orbicularis oculi :
1- Orbital part :
Origin : medial palpebral
ligament + adjoining bone.
Insertion :The fibres have no
lateral attachment, it loops return
to origin.
Action : closes eyelids by
throwing skin around orbit into
folds to protect eyeball.
2- Palpebral part :
Origin : medial palpebral
ligament.
Insertion : lateral palpebral raphe
& skin of eyelids.
Action : closes palpebral fissure
of eyelids gently (sleep) and
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dilates lacrimal sac.
Orbicularis oris :
Origin : maxilla, mandible & deep
skin.
Insertion : encircles oral orifice to
be inserted to the m.m lining the
inner surface of lips.
Action : compresses the lips
together to close the mouth
(sphincter muscle of lips).
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Muscle of Cheek : Buccinator Muscle :
Origin : from outer surface of
maxilla & mandible opposite the
molar teeth + from
pterygomandibular ligament.
Insertion :
1-upper fibres : into upper lip.
2-lower fibres : into lower lip.
3-middle fibres : decussate at the
angle of mouth.
N.supply : buccal branch of
facial N.
Action :
1- it compresses the cheeks & lips
against the teeth to prevent
accumulation of food in vestibule of
mouth.
2- it is used in wistling, when
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cheeks are distended with air.
Muscle of Cheek : Buccinator Muscle :
It is covered on
outside by
buccopharyngeal fascia &
buccal pad of fat.
Its deep surface is
lined by buccal mucosa.
It is pierced by :
1-parotid duct , opposite
upper 2nd molar tooth.
2-Buccal branch of
mandibular nerve
(sensory) to supply m.m
of cheek on the inner
surface of buccinator
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muscle.
Facial muscle Paralysis
• The facial ms. Are innervated by facial N.
• Cause : Damage to facial N. (by a tumor in
internal acoustic meatus or parotid galnd) /or
operation or infection in middle ear / or
perineuritis, Bell’s palsy in facial nerve canal.
• Results : Lower motor neuron lesion which
involves distortion of face+ drooping of lower
eyelid + angle of mouth will sag on the
affected side. /But Upper motor neuron lesion
is due to lesion of pyramidal tract and here
the upper face is normal because the neurons
supplying this part receive corticobulbar
fibres from both cerebral cortices.
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The Cranial Cavity
Contents of cranial cavity
1- the brain.
2-meninges of brain (dura, arachnoid &
pia mater) from outside inwards.
3-blood vessels of brain & meninges.
4-parts of cranial nerves.
5-Blood venous sinuses.
6- Hypophysis cerebri (pituitary gland).
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Dura Mater of Brain
It is a thick dense membrane which
consists of 2 layers (outer & inner).
The 2 layers are attached together
except at blood venous sinuses.
Outer endosteal layer :
-it covers inner surface of bones of skull.
-it is firmily attached to sutures of skull and
to foramen magnum, it does not extend
through foramen magnum .
Inner meningeal layer :
-it covers brain and continuous with dura
mater of spinal cord through foramen
magnum.
-it sends tubular sheaths around cranial
nerves as they pass through foramina in
skull.
-it sends 4 septa into cranial cavity to
divide cavity into spaces, these septa
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stabilize the brain within the cavity during
movement of head.
Dural Septa : 1- Falx Cerebri
It is a sickle-shaped fold of dura
that descends in the midline
between 2 cerebral hemispheres.
Attachment :
-its narrow anterior end is attached
to internal frontal crest & crista
galli.
-its wide posterior end is attached to
upper surface of tentorium cerebelli.
-venous sinuses in falx cerebri :
1- superior sagittal sinus : lies in its
upper convex fixed border.
2- inferior sagittal sinus : lies in its
lower concave free margin.
3- straight sinus : lies at line of
attachment of posterior end of falax
with tentorium cerebelli.
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2- Tentorium cerebelli
It is a crescentic fold of dura that roofs
posterior cranial fossa.
It separates the occipital lobe of
cerebrum above from cerebellum below.
Its free border :
-is concave and forms a gap called,
tentorial notch, for passage of midbrain
–it crosses above the attached border of
tentorium to be fixed at the 2 anterior
clinoid processes.
-at the point of crossing of the free &
attached borders : the trochlear &
oculomotor Ns. Pierce the tentorium to
enter lateral wall of cavernus sinus.
-at the apex of petrous temporal bone : the
inferior layer of tentorium is invaginated
anteriorly beneath the sup. Petrosal sinus
to form a recess called trigeminal cave
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which contains the trigeminal ganglion.
2- Tentorium cerebelli
Attached border :
-it is convex and directed peripherally.
-its posterior part is attached to the lips of
transverse sulcus.
-its anterolateral part is attached to the
lips of groove for superior petrosal sinus
(at the upper border of petrous temporal
bone).
-Its anterior end crosses below the free
border and is attached to the 2 posterior
clinoid processes.
In the median plane :
-the superior layer of tentorium
cerebelli is attached to falx cerebri.
-the inferior layer of tentorium cerebelli
is attached to falx cerebelli.
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2- Tentorium cerebelli
Venous sinuses in the
tentorium cerebelli :
1-straight sinus : at the line of attachment
of posterior end of falx cerebri with
tentorium cerebelli.
2-transverse sinus : in the posterior part
of the attached border.
3-superior petrosal sinus : in the
anterolateral part of attached border.
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3-Falx Cerebelli :
It is a small sickle-shaped fold of
dura placed in median plane below
tentorium cerebelli.
Its free anterior border projects
forwards between the 2 cerebellar
hemispheres.
Its posterior border is attached to
the internal occipital crest.
It contains the occipital sinus in
its posterior fixed border.
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4-diaphragma sellae :
It is a small circular fold of dura.
It forms the roof of sella turcica.
It has a centeral opening for passage
of the stalk of hypophysis cerebri
(pituitary stalk).
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Dural Nerve Supply
•
•
•
•
Trigeminal N.
Vagus N.
First 3 cervical nerves.
Sympathetic fibres around the meningeal
arteries.
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Dural Arterial Supply
• Internal carotid artery.
• Maxillary artery…. Middle meningeal artery,
it is the most important branch.
• Ascending pharyngeal artery.
• Occipital artery.
• Vertebral artery.
Meningeal Veins
Middle meningeal vein follows the branches of middle meningeal artery
and drains into the pterygoid venous plexus or sphenoparietal sinus.
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Middle meningeal artery
It is a branch of 1st part of maxillary
artery.
It reaches middle cranial fossa
through foramen spinosum to lie
between the meningeal & endosteal
layers of dura.
It passes forwards and laterally
grooving the squamous part of
temporal bone. Then it divides into :
1-large anterior (frontal) branch. &
2-small posterior (parietal) branch.
It divides into anterior & posterior
branches opposite a point 20mm
above center of zygomatic arch.
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Extradural hemorrhage
This is intracranial hemorrhage outside
the dura mater.
It results mostly from injury of middle
meningeal artery, usually occuring in the
region of the pterion (at anteroinferior part
of the parietal bone) as a result of a blow
over the side of the head.
A collection of blood,
(extradural hematoma) occurs between
the dura and the skull bones, stripping off
the periosteum of inner table of the bone.
The intracranial pressure rises producing
local pressure on the motor area of brain.
Blood may pass out through the fracture to
form a soft swelling under the temporalis
ms
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Arachnoid mater
It is a delicate, impermeable
membrane covering the brain, lying
between pia mater & dura mater.
It is separated from the dura by
subdural space, and from the pia by
subarachnoid space, which is filled
with cerebro-spinal fluid.
The arachnoid projects into the
venous sinuses to form arachnoid
villi, they are most numerous at
superior sagittal sinus, aggregations
of arachnoid villi are called arachnoid
granulations, where C.S.F diffuses
into bloodstream.
Cerebral arteries &veins & cranial
nerves lie in subarachnoid space.
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Cerebrospinal fluid
It is produced by the choroid
plexuses within lateral, 3rd & 4th
ventricles of brain.
It passes via 3 foramina in roof
of 4th ventricle to circulate in
subarachnoid space, upward
over surfaces of cerebral
hemispheres and downward
around spinal cord.
The spinal subarachnoid space
extends down as far as 2nd sacral
vertebra.
The fluid enters bloodstream by
passing into arachnoid villi and
diffuses into venous sinuses.
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Pia mater
It is a thin vascular membrane
that closely covering the brain.
It extends over the cranial
nerves and fuses with their
epineurium.
The cerebral arteries enter
the brain carrying a sheath of
pia mater.
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Venous Sinuses
They are blood channels between the
endosteal & meningeal layers of dura
mater.
The walls of sinuses are lined by
endothelium.
They receive tributaries from : the brain,
the diploe of skull, the orbit, & the internal
ear.
Paired sinuses are :
1-transverse sinuses.
2-sigmoid sinuses.
3-cavernus sinuses.
4-superior & inferior petrosal
sinuses.
5-sphenoparietal sinuses.
They differ from the veins in having no
valves, or muscles in their walls. So they
do not contract when they are ruptured
and bleeding is controlled only by
pressure.
Single sinuses are :
1-superior sagittal, 2-inferior sagittal, 342
straight sinus & 4-intercavernus sinus.
5-Occipital sinus.
Superior Sagittal Sinus
It lies in the upper fixed border of falx
cerebri.
It begins in front at frontal crest &
foramen cecum, where it receives :
vein from nasal cavity, then runs
backward grooving vault of skull.
At the internal occipital protuberance,
it is dilated to form the confluence of
the sinuses, here it deviates to one
side (usually the right) to become the
right transverse sinus.
It is connected to the opposite
transverse sinus and it receives the
occipital sinus.
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Tributaries and communications of the Superior
Sagittal Sinus
The sinus communicates with 2-3
venous lacunae on each side.
Numerous arachnoid villi &
granulations project into the lacunae,
which also receive the diploic &
meningeal veins.
It receives also the cerebral veins.
It communicates with veins of scalp
by emissary veins passing through
the parietal foramina.
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Inferior Sagittal Sinus
It lies in the free lower border of falx
cerebri.
It runs backward to join great
cerebral vein at free border of
tentorium cerebelli to form straight
sinus.
Straight Sinus
It lies at the junction of falx cerebri
with tentorium cerebelli.
It is formed by union of inferior
sagittal sinus & great cerebral vein.
It ends by turning to left to form the
left transverse sinus.
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Transverse Sinuses
Are paired sinuses, begin at the
internal occipital protuberance.
Right sinus is usually continuous
with the superior sagittal sinus, and
left sinus is continuous with the
straight sinus.
Each sinus occupies the attached
margin of tentorium cerebelli,
grooving the occipital bone.
They receive the superior petrosal
sinuses, cerebral & cerebellar veins,
& diploic veins.
They end by turning downward as
sigmoid sinuses.
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Sigmoid Sinuses
Are direct continuation of transverse
sinuses.
Each sinus turns downward and
medially and grooves the mastoid part of
temporal bone, here it lies behind mastoid
antrum.
Finally, it passes through jugular
foramen to join the internal jugular vein.
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Occipital sinus
It is a small sinus occupying the
attached border of falax cerebelli.
It begins near foramen magnum,
where it communicates with vertebral
veins and drains into the confluence
of the sinuses.
It connects the beginning of
transverse sinus with the end of
sigmoid sinus.
May be single or paired.
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Cavernus sinuses
Are lie in middle cranial fossa on
each side of body of sphenoid bone
( hypophyseal fossa).
Each sinus extends from superior
orbital fissure anteriorly, to apex of
petrous temporal bone posteriorly.
Inside the sinus :
1- internal carotid artery surrounded
by sympathetic plexus.
2- abducent nerve.
In the lateral wall of cavernus
sinus :
1-oculomotor nerve.
2-trochlear nerve.
3-ophthalmic nerve of trigeminal N.
4-maxillary nerve of trigeminal N.
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Cavernus sinuses
Tributaries :
1-superior & inferior ophthalmic veins.
2-cerebral veins.
3- sphenoparietal sinus, along posterior
margin of lesser wing of sphenoid.
4-central vein of retina.
Each sinus drains posteriorly into :
superior & inferior petrosal sinuses
and inferiorly into : pterygoid venous
plexus.
The 2 sinuses communicate with
each other by anterior & posterior
intercavernous sinuses, which run in
diaphragma sellae.
Each sinus has important
communication with facial vein through
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superior ophthalmic vein.
Superior & inferior Petrosal sinuses
Are small sinuses lying on the
superior & inferior borders of
petrous part of temporal bone.
The superior sinus drains the
cavernus sinus into transverse
sinus.
The inferior sinus drains the
cavernus sinus into internal jugular
vein.
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It is the master endocrine gland, which
attached to brain by the infundibulum.
Hypophysis Cerebri
(Pituitary
gland)
Site: : sella turcica of sphenoid bone
(hypophyseal fossa).
It has 2 lobes, anterior lobe or
adenohhypophysis and posterior lobe or
neuro-hypophysis.
Superiorly : diaphragma sellae, which
has a central aperature to allow passage
of infundibulum.
Inferiorly : body of sphenoid+ sphenoid
air sinuses.
Laterally : cavernus sinus.
Posteriorly : dorsum sellae, basilar
artery, & pons.
Blood supply : superior & inferior
hypophyseal branches of internal carotid
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artery / veins drains into intercavernous
sinuses.
Diploic Veins
They are thin- walled, valveless
veins lying in the diploe of skull
(between the inner & outer tables
of the bones of skull).
They communicate with the
meningeal veins & dural venous
sinuses.
They include : frontal, temporal
& occipital diploic veins.
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Emissary Veins
They are small valveless veins,
pass via foramina in the skull and
connect the dural venous sinuses
with veins outside the skull.
Function : they help to equalize
the pressure in veins outside the
skull and in the dural venous
sinuses.
Their danger : infection outside
the skull may spread along the
emissary veins to reach the dural
venous sinuses and produce
septic thrombi.
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Intracranial part of Internal Carotid
Artery
:
It enters the cranial cavity through
the carotid canal in petrous part of
temporal bone.
It passes into foramen lacerum to
enter the cavernus sinus.
It lies with the abducent nerve on
the floor of cavernus sinus.
It pierces the roof of cavernus sinus
to lie on the medial side of anterior
clinoid process and divide into
anterior & middle cerebral arteries.
Branches :
1-superior & inferior hypophyseal
arteries to pituitary gland.
2- meningeal branches.
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