Neuro: 8:00 - 9:00Scribe: Brittney Wise

Thursday, March 12, 2009Proof: Laura Adams

Dr. BimczokPterygopalatine Fossa, Nose and Paranasal SinusesPage1 of 10

Abbreviated Terms: PPF (Pterygopalatine Fossa)

NOTE: The italicized words are the notes located under each slide. She did not necessarily address all of these notes in class but I included them in this transcript for convenience. They were definitely a study aid for the 1st exam because many of the test questions come from the notes below the slides.

  1. Introduction [S1]: This is a frontal section of the head. You can see a few structures that you will be able to ID at the end of this lecture.
  2. [S2] Pterygopalatine Fossa, Nose, Paranasal Sinuses, and Dissection
  3. Pterygopalatine Fossa – not the easiest region in the heads
  4. Nose
  5. Paranasal Sinuses
  6. Dissection
  7. [S3] Pterygopalatine Fossa
  8. She has made an analogy for this: “A crossroads in a crevice”
  9. Showed 5 points south being a crossroads and symbolizing the PPF. This is where the maxillary nerve enters and goes off in many directions. At a crossroads you may have more than one street and sometimes more than one lane. So, in the PPF you can more than one structure go through more than one road.
  10. You have to imagine that you are putting this crossroads (3 dimensional) into a crevice (other picture).
  11. [S4] Picture of the Pterygopalatine Fossa and Landmarks
  12. Here is your infratemporal fossa and here is your PPF and you are looking into the PPF through the pterygomaxillary fissure.
  13. The PPF is bordered by the maxilla bone anteriorly; the sphenoid bone superiorly and posteriorly: the perpendicular plate of the palatine bone medially.
  14. The palatine bone (blue in the diagram is the long arm of the “L”) is shaped like an “L”. You have a perpendicular plate and a horizontal plate. It is part of your palate so it is considered medial.
  15. The blue that you are looking at is the perpendicular plate and is actually the long arm of the “L” and the horizontal plate will kind of go off medially from here.
  16. If you are looking at a real skull you would have the zygomatic process covering all these structures.
  17. Roof - greater wing of sphenoid
  18. post. wall - lat. pterygoid plate
  19. med. wall - perpendicular plate of the palatine.
  20. ant. wall - post. surface of the maxilla
  21. Ant and post wall converge inferiorly
  22. [S5] Real Skull showing location of Pterygopalatine Fossa
  23. Here the skull is tilted and you can see the zygomatic process that is partly removed. Here is the sphenoid bone, pterygoid process, and this region where the red arrow is pointing to is the exit of the PPF.
  24. Is a continuation of the Infratemporal fossa
  25. [S6] Pterygopalatine Fossa
  26. The yellow oval is the PPF and you have 3 main structures that enter it:
  27. The maxillary nerve (V2) of the trigeminal
  28. The maxillary artery
  29. The 3rd part is the pterygopalatine part; the 3rd part is a nerve that is composed of parasympathetic and sympathetic fibers of the greater and deep petrosal nerve and it is called the nerve of the pterygoid canal or the Vidian nerve(NOTE: the Vidian nerve is the same thing as the greater and deep petrosal nerve)
  30. The maxillary nerve is in the middle cranial fossa to start with as are the greater and deep petrosal nerves.
  31. The maxillary artery comes from the infratemporal fossa.
  32. The maxillary nerve exits the middle cranial fossa through the foramen rotundum and enters into the PPF.
  33. The pterygomaxillary fissure is how the maxillary artery enters the PPF.
  34. The nerve of the pterygoid canal comes through the pterygoid canal.
  35. So, foramen rotundum, pterygoid canal, and pterygomaxillary fissure are our access routes into the PPF.
  36. Greater and deep petrosal nerves form the Nerve of the Pterygoid canal (or Vidian nerve)
  37. [S7] Pterygopalatine Fossa
  38. You have one exit into the orbit via the inferior orbital fissure, one exit into the nasal cavity via the sphenopalatine foramen, and another exit into the oral cavity and that’s the greater palatine canal or just the palatine canal.
  39. [S8] Maxillary Artery in the PPF
  40. Let’s start with the 3rd part of the maxillary artery.
  41. The maxillary artery enters through the pterygomaxillary fissure. Before this it gives off one branch to the posterior superior alveolar artery.
  42. Then the maxillary artery has branches going to the orbit and face, into oral cavity, and into the nasal cavity.
  43. The infraorbital artery leaves through the inferior orbital fissure.
  44. The sphenopalatine artery to the nose leaves through the sphenopalatine foramen.
  45. The descending palatine artery leaves through the palatine canal.
  46. We have one artery that makes the PPF a 2-way street and that is the artery of the pterygoid canal (just a little branch of it).
  47. The pharyngeal branch to the pharynx is present but not shown on this slide.
  48. [S9] Maxillary Artery (part 3) Lateral View
  49. This is a head that has been dissected and part of the orbit and zygomatic process has been removed. Here is a muscle that you have already dissected and is named the lateral pterygoid muscle.
  50. This muscle defines the 3 parts of the maxillary artery. Part 2 is in the region of the pterygoid muscle. Part 3 is in the PPF. You can see the infraorbital artery going into the orbit.
  51. The posterior alveolar artery to the teeth is also seen. The middle and anterior come off the infraorbital artery.
  52. The 3RD PART OF THE MAXILLARY A. also lies in the pterygopalatine fossa. It has numerous brs., the most imp. of which are:

1) INFRAORBITAL A. --- In the floor of the orbit this artery gives off the MID. SUP. ALVEOLAR A. to the

premolars and the ANT. SUP. ALVEOLAR A. to the incisors and canine.

2) POST. SUP. ALVEOLAR A. --- Supplies the molar teeth.

3) DESCENDING PALATINE A. --- Not shown.

4) SPHENOPALATINE A. --- Not shown.

  1. [S10] Maxillary Artery (part 3) Medial view
  2. Here is your nasal septum and your cranial cavity. The pterygoid plate of the sphenoid bone can be seen and you can also see the pterygopalatine foramen that comes from the PPF into the nasal cavity. Here is also the sphenopalatine artery that passes through that foramen too.
  3. Here is an artery that descends to the palate aka the descending palatine artery. The greater and lesser palatine arteries branch off of it.
  4. And again here is your posterior superior alveolar artery.
  5. The other BRS. OF THE 3RD PART OF THE MAXILLARY A. are shown here. The DESCENDING PALATINE A. splits into two branches. --- The greater and lesser palatine arteries which supply the hard and soft palates (resp.). The SPHENOPALATINE A. passes through the foramen of the same name to supply the nasal cavity. Note that the 2nd part of the maxillary a. (in the infratemporal fossa) passes through the pterygomaxillary fissure to enter the pterygopalatine fossa.
  6. [S11] Maxillary Nerve in the PPF
  7. Maxillary nerve enters through the foramen rotundum and it carries on through the inferior orbital fissure as the infraorbital nerve and the zygomatic nerve.
  8. Found in the PPF is the pterygopalatine ganglion which is the parasympathetic ganglion of the head. Some fibers of the maxillary nerve which are sensory and not parasympathetic at all run through this ganglion, but they are called pterygopalatine nerves because they connect this main branch of the nerve to the ganglion.
  9. Off of this ganglion, the branches to the oral and nasal cavities come off.
  10. Through the sphenopalatine foramen, access to the nose, we have posterior superior medial nasal rami and lateral nasal rami (you can just call them medial and lateral nasal rami.) These innervate the nasal cavity and the ones on the septum are the medial branches and the lateral ones are on the lateral side of the nasal cavity.
  11. The biggest one off the medial rami is the nasopalatine nerve.
  12. We also have the greater and lesser palatine nerves running through the palatine canals into the oral cavity.
  13. [S12] Maxillary Nerve (V2) Lateral View
  14. Some of the bones have been dissected away to open up the view into the orbit and into the maxillary sinus. You can still see the mucosa that covers the sinus if the dissection is done well.
  15. Here is your trigeminal nerve showing all 3 branches: V1 goes up, the maxillary branch (V2) going through the foramen rotundum leading into the PPF, and V3 going through the foramen ovale.
  16. The 1st branch that comes off V2 is the zygomatic nerve that further branches into the zygomaticofacial and the zygomaticotemporal nerves. Then you see the infraorbital nerve that runs through the orbit and then through the infraorbital canal and then comes out onto the face.
  17. The 1st branch that comes off of this main branch after the zygomatic nerve is a nerve that innervates the last 2 molars: the posterior superior alveolar nerve (PSA). This is important for dentists because you can anesthetize this with a local anesthetic to do work on the last 2 molars. Through the inferior orbital fissure you have direct access into the orbit so there is a risk that some of the anesthetic might leak into part of the orbit and numb some of the nerves there when trying to get the PSA. An example of a nerve in the orbit that you could get would be the abducens nerve which is on the lateral aspect of the orbit.
  18. There are also middle and anterior alveolar nerves and they form a plexus with dental and gingival branches.
  19. These anterior and middle alveolar nerves run along the wall of the maxillary sinus. So here is the maxillary sinus and nerve and these branches actually run through the mucosa. This is important clinically because if you have an infection of the maxillary sinus you can have pain that feels like it’s coming from the maxillary teeth, aka referred pain. So, the pain is not coming from the teeth but rather a sinus infection because the area is supplied by the same nerves. (A blue circle appeared later on in the slide to show where you would give the block. This circle was not on the original power point.)
  20. Here is the ganglion with the pterygopalatine nerves running through it.
  21. TWO OF THE MOST IMP. CONTENTS OF THE PTERYGOPALATINE FOSSA ARE THE MAXILLARY N. (V2) & THE PTERYGOPALATINE GANGLION. V2 enters the fossa posteriorly (via f. rotundum) and leaves the fossa anterosuperiorly (via inf. orbital fissure) to become the infraorbital n. V2 HAS NUMEROUS BRANCHES, INCLUDING THE FOLLOWING:

1) ZYGOMATIC N. --- This nerve enters the orbit and splits into the ZYGOMATICOTEMPORAL & ZYGOMATICOFACIAL NN. which are cutaneous to the temple and face.

2) INFRAORBITAL N. --- This is the terminal part of the maxillary n. Before reaching the infraorbital f. tosupply skin of the face, the infraorbital n. gives off the MID. SUP. ALVEOLAR N. to the maxillarypremolars and the ANT. SUP. ALVEOLAR N. to the maxillary incisors and canine. These nerves run within the bone of the wall of the maxillary sinus and also supply the mucous membrane of the sinus.

3) POST. SUP. ALVEOLAR N. --- This nerve arises directly from V2. It enters the post. sup. alveolar foramina and canals to supply the maxillary molars and the mucosa of the maxillary sinus.

4) PTERYGOPALATINE NN. --- These short nerves connect V2 with the pterygopalatine ganglion. Theycontain primarily sensory fibers (GSA) of V2 which pass through the ganglion WITHOUT SYNAPSE tobe distributed to the pharynx, palate and nasal cavity. The branches of distribution to these areas areillustrated in the following plate.

  • Clinical relevance: infraorbital nerve
  • Trigeminal nerve often involved in referred pain
  • Pain from abcessed tooth can be described as ocular pain! – overload!
  1. [S13] Maxillary Nerve (V2) Medial View
  2. Looking from this view, again here is our main branch and here is our ganglion. You wouldn’t usually be able to see that because the palatine canal is covered by a thin bony lamina. You might be able to see the ganglion because it’s located more or less immediately behind the sphenopalatine foramen.
  3. Here is our medial aspect: you can see the ganglion and the nerves descending into the oral cavity and those are the greater and lesser palatine nerves.
  4. Greater palatine nerve supplies the hard palate
  5. Lesser palatine nerve supplies the soft palate posteriorly.
  6. Here is the canal that runs through the body of the sphenoid or the base of the pterygoid process and that’s the nerve of the pterygoid canal formed by the greater petrosal nerve and the deep petrosal nerve.
  7. Here again, is the little branch to the pharynx called the pharyngeal branch.
  8. In this MEDIAL VIEW of the pterygopalatine ganglion some of the OTHER (INDIRECT) BRANCHES OF V2 can be seen:

1) PHARYNGEAL BR. --- Sensory to the roof of the pharynx (above the auditory tube).

2) GR. & LSR. PALATINE NN. --- Sensory to the hard and soft palates (resp.).

3) POST. SUP. & POST. INF. LAT. NASAL BRS. --- Sensory to the lateral wall of the nasal cavity.

4) NASOPALATINE N. --- Sensory to the septum (med. wall) of the nasal cavity.

  • Also note the PTERYGOID CANAL (containing a nerve of the same name) which passes from the f. lacerum through the sphenoid to open into the post. wall of the pterygopalatine fossa.
  1. [S14] Pterygoplatine ganglion
  2. This is the parasympathetic ganglion of the head. The fibers that synapse here are parasympathetic fibers and you know that there are only 4 cranial nerves that have parasympathetic fibers. The greater petrosal nerve has fibers from the intermediofacial nerve, cranial nerve #7. Again this is a paramedian section: the orbit and the nasal cavities have been open.
  3. This is your cranial cavity and take note of your internal auditory meatus with the facial nerve and the vestibulocochlear nerve entering into the petrous bone.
  4. The facial nerve has its own sensory ganglion, the geniculate ganglion. In this region, this little nerve comes off and that’s the greater petrosal nerve and it crosses the area of the foramen of lacerum and foramen ovale and enters the pterygoid canal. It then synapses in this ganglion here. The parasympathetic fibers then attach themselves to all these fibers of the maxillary nerve that we have already talked about and they go into the nasal cavity to supply the nasal glands because that’s where we need parasympathetic innervation.
  5. We also have glands in the palate, the palatine glands, so again the parasympathetic fibers of the greater petrosal nerve after synapasing at the ganglion attach themselves to the greater and lesser palatine nerve of the maxillary and innervate the glands of the palate.
  6. The most important gland that is innervated by the fibers of the greater petrosal nerve is the lacrimal gland.
  7. Why don’t we just call it the greater petrosal nerve (not sure what she’s talking about here)? Because we have other fibers attaching to it (the structures labeled in green).
  8. They are sympathetic fibers that run together with the parasympathetic fibers as the deep petrosal nerve in the pterygoid canal and they come like any other sympathetic fibers in the head and come off of the sympathetic ganglion of the neck region and they attach themselves to the internal carotid as a carotid plexus and actually the internal carotid nerve and goes through the carotid canal.
  9. Then these fibers attach to this greater petrosal nerve and also run with all these fibers. They don’t innervate the glands directly but they innervate the blood vessels and if you reduce the blood supply to a gland part of the secretions are reduced.
  10. SQ: inaudible
  11. ANSWER: The sympathetic fibers travel with the carotid artery. The parasympathetic fibers come off the facial nerve in the region of the geniculate ganglion.
  12. The PTERYGOPALATINE GANGLION is a parasympathetic ganglion. Only presynaptic parasympathetic fibers from the gr. petrosal br. of VII synapse in this ganglion (GSA fibers from V2 and postsynaptic sympathetic fibers from the deep petrosal n. pass through the ganglion without synapse). Postsynaptic parasympathetic fibers supply the gls. of the orbit (lacrimal gl.), roof of the nasopharynx, palate and nasal cavity (secretomotor). (Note: the postsynaptic sympathetic fibers in the deep petrosal n. are destined mainly for blood vessels). Very strange
  13. [S15] Parasympathetic and sympathetic fibers to lacrimal gland
  14. The Pterygopalatine ganglion supplies the lacrimal gland. The is a lateral view: here is the orbit, maxillary sinus with these branches to the teeth, and here is the ganglion in the PPF and here is V2.