Disscus possible routes of infection into the cavernous sinus from each of the following locations. As always, include key relations for each anatomical pathway. (30 pts)
face near the lateral aspect of the upper lip
lower border of mandible near the angle
scalp (What fascial boundaries are compromised?)
ischiorectal fossa (this is not a typographical error)
frontal sinus (air sinus)
sphenoid sinus (air sinus)
mastoid air cells
ethmoid air cells
prostate (this is not a typographical error)
One of the most commonly fractured bones in males is the body of the left mandible. What neurovasuclar structures are vulnerable? Discuss the entire course of these structures from origin to terminal distribution.
Discuss the cutaneous innervation of the nose. Include the specific nerves involved and the anatomic pathways followed by these nerves from their origin. (15 pts.)
The galea aponeurotica and the rest of the occipitofrontalis muscle define a potential space. Lacerations of the scalp can introduce infection into this space. From this space, emissary veins can transmit infectious material to an intracranial location. What are the boundaries of the potential space of the scalp known as the the loose areolar space? How deep must a scalp laceration penetrate before concerns of intracranial infection are primary?
Section of which facial muscle exposes the infraorbital n.?
Several attendees mentioned that they could anesthetize both the maxillary nerve and the mandibular nerve from injections into the infratemporal fossa. Thus, a few persons incorrrectly concluded that the maxillary nerve traversed foramen ovale. Eplain maxillary nerve anesthesia following infratemporal fossa injections? Hint. Mandibular nerve blocks are done by passing a needle through the mandibular notch and stopping the needle at the lateral pterygoid plate. The needle is then "walked" to the posterior free edge of the lateral pteryoid plate. At this location, the needle is at the opening of the foramen ovale. Injection here anesthetizes the mandibular nerve. If, instead of walking the needle posterior, the needle is angled anterior, the maxillary nerve is apt to be anesthetized. This is a strong hint.
How would you determine whether a facial nerve lesion is distal to the stylomastiod foramen, within a specific part of the facial canal, or at the internal acoustic meatus? Suggest clinical procedures to test the functional components of the facial nerve.
Explain the symptoms of Horner's syndrome? What structure within the middle cranial fossa may be damaged if the symptoms are limited to the region of the orbit? (4 pts)
A patient has paralysis of the muscles of facial expression. There are salavitory deficits on the same side as the paralysis. Tearing of the eyes is normal. What is the location of neural damage that could cause this condition? What additional tests (observations) would you do to confirm the location? Support your answer. (8 pts)
A patient has an infection on the lateral side of the nose. There is loss of lateral gaze (inability to abduct the eye) on the same side. Discuss the relevant spread of infection. What structures are vulernable to injury?
An early procedure to limit spread of a facial infection into the cavernous sinus was to ligate (suture closed) facial vein communications into the orbit (e.g. supratrochlear, supraorbital, and other veins entering the orbit from the face). Unfortunately, this procedure is not entirely effective. Suggest an additional venous ligation and explain.
Horner's Syndrome refers to symptoms that result from a disruption of sympathetic innervation to the head. Briefly discuss the anatomy pertaining to each of the following symptoms..
Mild ptosis (drooping) of the upper eye lid
"red eye" (conjunctival injection)
Nasal congestion and "runny" nose
Flushing (redness and warmth) and dryness of the facial skin
Discuss the relations (six directions) of the sphenoid sinus. Include mention of structures at risk during surgery involving the sphenoid sinus.
How would you determine whether a facial nerve lesion is distal to the stylomastiod foramen, within a specific part of the facial canal, or at the internal acoustic meatus? Use your knowledge of facial nerve anatomy and functional components. Suggest procedures to exhaustively test the functions of each branch of the facial nerve.
Discuss the boundaries (6 directions), contents, and relations of the cavernous sinus. In the event of infection, discuss the cascade of symptoms from early onset to death.
Discuss the relations of the anterior scalene. Your discussion would benefit from inclusion of at least 7 arteries, 5 nerve roots, 1 celetrated nerve having contributions from roots of both the cervical and the brachial plexuses (doesn't this take your breath away), 1 bony landmark associated with carotid compression, a noted component of the sympathetic nervous system, glandular tissue often targeted by surgeons, and a bevy of additional relations. This is a fun one.
Discuss the relations of the posterior belly of the digastric. Your discussion would benefit from inclusion of at least 5 arteries, 3 cranial nn medial, 1 cranial n. lateral, a bony landmark used by surgeons and anesthesiologists, a moveable bone involved in swallowing, and a few few more structures to take you from 8 to 10 points.
Discuss the relations of the hyoglossus. Your discussion would benefit from inclusion of two nerves on the lateral side and a cranial nerve on the medial side. Naturally, a few arteries are in the area. What about the pterygomandibular raphe? Wait, there is more.