Download Pterygopalatine fossa

Pterygopalatine fossa
I recommend you to see this video before you study the lecture "it gives
a good visualization to the fossa" it's only 4.43 minutes .
http://www.youtube.com/watch?v=ORtExv3qKU8
I write only what the doctor said in the lecture .
Refer to the pictures in the slides .
HERE WE START The pterygopalatine fossa is tear-drop in shape ,lies
between bones of the lateral side of the skull .
Walls "boundries" of the fossa are formed by :
Posteriorly and roof : the sphenoid bone .
Anteriorly : the posterior wall of the maxilla .
Medially : palatine bone ,the sphenopalatine foramen which transmit
the blood vessels and nerves to the nasal cavity .
That’s why this fossa is important because it contains stuctures which
pass to the nasal cavity, nasopharynx and oral cavity .
The pterygopalatine fossa is space between the bones and this space
contains important structures like pterygopalatine ganglia ,maxillary
nerve and maxillary artery .
The psterior wall of the maxilla lies anterior to the fossa "anterior
boundry" .
The importance of sphenoid bone in it's two foramina between the
middle cranial fossa and pterygopalatine fossa :
1-foramen rotundum : between the middle cranial fossa and the
pterygopalatine fossa "the maxillary nerve pass through it to the
pterygopalatine ganglia" .
2-pterygoid canal : below the foramen rotundem ,the nerve of pterygoid
canal pass through it ;also called vidian nerve"sympathetic and
parasympathetic nerve" .
*The beginning of pterygoid canal is in the middle cranial fossa where it
lies in the roof of the foramen lacerum,the great petrousal nerve pass
through it ;also the internal carotid artery pass through the roof of the
foramen lacerum after it enter the carotid canal "the carotid canal is in
the wall of petrous bone" ,we also see the artery in the cavernous sinus
when it make the S –shape .
The nerve of pterygoid canal pass below it ,in the pterygoid canal,
the great petrousal nerve is the parasympathetic nerve in the pterygoid
canal and the deep petrousal is the sympathetic .
Note : we take a lot of petrousal nerves :
-Lesser petrousal nerve associated with the otic ganglia .
-Greater petrousal nerve which make synapse in the pterygopalatine
ganglia .
this is a parasympathetic nerve so there is preganglionic and
postganglionic fibers ,that’s why the pterygopalatine ganglia is a
parasympathetic ganglia .
-Deep petrousal nerve ,a branch of the internal carotid plexus
this is sympathetic nerve so there is only postganglionic fiber which
comes from the superior cervical sympathetic ganglia .
> The greater petrousal and deep petrousal unite to form nerve of
pterygoid canal "vidian nerve" so this nerve contain sympathetic and
parasympathetic fibers .
The importance of the pterygopalatine fossa that it communicate with
the surrounding spaces "Gateways of the pterygopalatine fossa" :
1-Middle cranial fossa by foramen rotundum and pterygoid canal .
2-Nasopharynx by palatovaginal canal ,pharyngeal branches either
"nerves and vessels" pass through it from the ganglia and third part of
maxillary artery .
*The maxillary artery divides into 3 parts "first ,second and third" by the
lateral pterygoid muscle
3-palatine canal between the maxilla and the sphenoid ,link the fossa to
the oral cavity…it contains nerves and blood vessels .
The nerve is the palatine nerve which divide into greater palatine and
lesser palatine nerve which pass through the greater palatine and lesser
palatine foramen , respectively .
The lesser palatine nerve goes to the soft palate ,but the greater
palatine nerve goes to the hard palate as far as the incisive foramen then
it pass through it to the nasal cavity .
4-pterygomaxillary fissure :this is a space between the pterygopalatine
fossa and the infratemporal fossa ,it's name indicate that it lie between
the pterygoid and the maxilla .
This fissure contain nerve and artery ;the nerve exit the pterygopalatine
fossa to the infratemporal fossa ,but the artery enter the
pterygopalatine fossa from the infratemporal fossa "inverse to each
other".
5-sphenopalatine foramen link the fossa to the nasal cavity ,all the
nerves and arteries which go to the nasal cavity pass through it
Like sphenopalatine artery and sphenopalatine nerve ,each one divides
into long and short branches sphenopalatine .
The long sphenopalatine nerve is very important to the septum ;the long
sphenopalatine artery anastomose with branch of the facial artery"the
long sphenopalatine artery is responsible for epistaxis ,although it's
common from the facial branch".
6-inferiororbital fissure link the pterygopalatine fossa with the orbital
cavity ;the maxillary nerve pass through it ,then it enter immediately in
the floor of the orbital cavity in a canal or groove to exit from the
ifraorbital foramen as infraorbital nerve "so the maxillary nerve is called
infratemporal nerve at it's end".
The artery is the same ;when the third part of maxillary artery reach the
pterygopalatine fossa ,also it enters the infraorbital fissure and pass
through a groove ,canal and foramen then it ends as infraorbital artery .
Contents of the pterygopalatine fossa :
1- The maxillary nerve branch of the trigeminal nerve ,pure sensory
,pass to the upper jaw "sensory to everything in the upper jaw"
The mandibular nerve pass to the lower jaw but it contains
sensory and motor fibres .
2- Terminal part of maxillary artery this is the third part ,important
because it's branches is in the pterygopalatine fossa .
the branches of the artery ,nerve and ganglia is the same e.x.
pharyngeal branches to the nasopharynx ,orbital branches pass to the
orbital cavity ,sphenopalatine branches to the nose ,palatine
branches to the oral cavity .
*Pterygopalatine ganglia is a parasympathetic ganglia ;we also took
otic ganglia ,submandibular ganglia and ciliary ganglia .
This 4 ganglia is a parasympathetic ;we call it parasympathetic ganglia
because the synapse is in the ganglia ,preganglionic, and
postganglionic exit from it .
So when we talk about the pterygopalatine ganglia ;we must know
the sympathetic ,parasympathetic and sensory .
The sensory is from the maxillary nerve , the maxillary gives two
sensory fibers to the ganglia .
The preganglionic parasympathetic from the greater petrousal
synapse in the ganglia while the sympathetic from the deep petrousal
pass without synapsing because it's postganglionic fiber .
After the sympathetic and parasympathetic reach the ganglia ,they
distributed through the branches of the maxillary nerve .
So the branches of the maxillary nerve carry sympathetic
,parasympathetic and sensory fibers
3- The veins same as the arteries ,also the same names .
4- The lymphatics .
Pterygopalatine ganglion
Largest parasympathetic ganglia in the head .
*Geniculate ganglia of the facial nerve ,origin of the parasympathetic
through the great petrousal nerve .
*Superior cervical ganglia ,origin of the postganglionic sympathetic
through the deep petrousal nerve .
Nerve of pterygoid canal consist of sympathetic fibers "great
petrousal " and parasympathetic fibers "lesser petrousal" .
They distribute from the gnglia through the V2 nerve "maxillary" by
two small branches of the maxillary nerve to the ganglia .
There are 3 branches of the trigeminal ganglia which lie in the middle
cranial fossa : V1 ophthalmic ,V2 maxillary ,V3 mandibular .
How the sympathetic and parasympathetic fibers reach the lacrimal
gland from the pterygopalatine ganglia ?
From the ganglia by two small branches"twins" of the maxillary nerve
, then from the maxillary nerve by the zygomatical branch which
divide into zygomaticofacial and zygomaticotemporal "these are
sensory branches to the facial and temporal respectively" ,then by
the zygomaticotemporal which pass the fibers to the lacrimal nerve
and from it ,the fibers reach the lacrimal gland .
*The zygomatic branch pass through the inferior orbital fissure .
Branches of the maxillary nerve :
1- Orbital branches to orbital cavity especially to the periosteum
;also to the sphenoidal and ethmoidal air sinuses .
2- Pharyngeal branches to nasopharynx and it innervates glands
there .
3- Palatine "divide into greater and lesser" and sphenopalatine
"divide into long and short" .
4- Posterior superior alveolar ; We said that the maxillary nerve is
the inverse of the maxillary artery in it's way ,so it enters the
infratemporal fossa through the pterygomaxillary fissure WHY
IT COME HERE ? to give the posterior superior alveolar nerve
So it's branch of maxillary nerve in infratemporal fossa
It pass along the posterior wall of the maxilla to last upper 3
molars ;when the maxillary nerve pass to the orbital cavity
through inferior orbital fissure then through the groove and
canal to emerge finallt as infraorbital nerve WHY IT PASS
THROUGH THE GROOVE AND CANAL ? to give middle and
anterior superior alveolar branches "so these branches arise
from the maxillary when it pass through the groove of the floor
of the orbital cavity" ;they innervate the upper
premolar,canine and incisors .
5- Infra-temporal nerve :when it arise from the foramen ,it gives
palpebral to the skin of the lower eyelid ,nasal to lateral wall of
the nose ,labial to the upper lip and sensory to the skin .
6- Meningeal branches to the dura in the middle cranial fossa .
*Some notes from Qs :
-the zygomatic nerve divide into zygomaticotemporal +
zygomaticaofacial ; the zygomaticotemporal pass to the skin
over the temporal but it carries with it sympathetic and
parasympathetic which go to the lacrimal nerve .
-the maxillary nerve and it's branches is purely sensory to the
upper jaw .
Now we will start with the maxillary artery
The maxillary artery is a branch of the external carotid artery
The terminal branches of the external carotid artery is the
maxillary artery and superficial temporal artery WHERE? In the
parotid gland
The lateral pterygoid muscle divide the maxillary artery into 3
parts ; the 1st part lie before the muscle ,the 2nd part is related
to the muscle "either it pass deep or superficial to the muscle"
,the 3rd part lie after the muscle "in the infratemporal fossa
then it pass through the pterygomaxillary fissure to reach the
pterygopalatine fossa where it gives the same branches as the
nerve" .
We said that it's way is inverse to the nerve
The 1st part :lies in the medial side of the neck of mandible
"above the artery is the auriculotemporal nerve while below it
is the maxillary vein";it gives 5 branches ,all of them enter
foramen or fissure :
1- two arteries to external ear ,they enter the external auditory
meatus "auricular and temporal arteries" .
2-two arteries go upward through the base of skull "middle
meningeal through the foramen spinosum and accessory
middle meningeal through the foramen ovale" ;they called
meningeal because they supply the dura matter .
3-descending branch "inferior alveoular" which enter in the
mandibular foramen and this branch which gives blood supply
to all lower teeth "here the artery is different from the nerve
because the it's a branch of the mandibular nerve ;both the
artery and nerve enter the mandibular foramen" .
The 2nd part : related to the lateral pterygoid muscle ;it gives
muscular arteries to the muscles of mastication "temporalis
,masseter ,media pterygoid and lateral pterygoid" .
The 3rd part : it gives :
1- The posterior superior alveolar ,it pass with the nerve to the
upper last three molars .
2- Palatine "greater and lesser" ;the lesser palatine artery
doesn't mentioned in the slides because it's too small to be
seen .
3- Sphenopalatine "long and short" .
4- in the orbital cavity ;the 3rd part gives anterior and middle
superior alveoular branches and ends as infra-orbital artery
"which also gives palpebral ,nasal and labial" .
5- pharyngeal .
6- the artery of the pterygoid canal .
*So the distribution is the same as the nerve .
*Sphenopalatine artery gives posterior lateral nasal
branches and posterior deptal branches .
veins
-All the veins drain to the pterygoid plexus in the
infrapterygoid fossa .
-The pterygoid plexus of veins is a collection related to the
lateral pterygoid muscle "surrounding the muscle" .
-The pterygoid plexus ends by draining to the maxillary vein
which join the superficial temporal vein in the parotid
gland to form retromandibular vein .