today's lecture is entitled a cranial nerves and the autonomic ganglia in the head my name is Carlos Andres orskian I am the author of this lecture and will narrate it for you much of the material I will present to you in this lecture is taken from a book a co-author with my colleagues Joel valenski and Wendy Robertson the title of the book is the clinical anatomy of the cranial nerves the nerves of old Olympus tiring top you will see in a moment why he chose his title to begin the lecture I paraphrase Gertrude's dying a cranial nerve it's a nerve it's a nerve and as much as I admire Miss Stein she missed the boat on this one the cranial nerves are magical these nurse play an essential role in the processes that allow you to experience the wonder of the world around you that is to experience smell taste sight and hearing to maintain your balance and also to feel the wind on your face a kiss on your lips and to express feelings using the muscles of your face without ever being consciously aware that you're doing so similarly speaking singing good or bad and eating are all directly controlled by the cranial nerves in fact one cranial nerve the tenth nerve or vagus is responsible for controlling digestion from your lips to almost the end of your digestive tract and the same nerve regulates heart rate breathing and speech in contrast the nurse of the rest of your body the spinal nerves primary control voluntary muscle movement and conveys simple Sensations for example touch but do not have the Finesse of the cranial nerves in other words we think the spinal nerves are rather mundane in cranial nerves are well as we said at the beginning magical but I still recommend a rose it's a rose as a rose to you let's now superimpose a dissection of the cranial nerves as they emerge from the base of the brain on a Netter drawing of where the cranial nerves travel to and exert a function at their final destinations and at this point let's list the 12 cranial nerves you'll need to learn them and be able to recall what they do for the rest of your careers so I urge you to spend some time with them but don't worry there are mnemonics to help you memorize the names of the nerves and here's the most well-known mnemonic for the names of the cranial nerves and the reason we name our book as such on Old Olympus tiring top of Finn and German beat some hops the beginning of each word corresponds to the first letter of the corresponding nerve if you have a grandfather or grandmother who graduated medical school in the 1950s I'm sure they will know this mnemonic I did try and find out who first came up with it however but was unable to find out I'm also providing a different version from the 1980s and I've read where the Harry Potter generation has come up with their own mnemonic it is up to you to decide how you'll remember the names of the cranial nerves but you must learn them because you will need to apply them in clinical medicine and now come to the objectives of this lecture here I list three features that you must know for each cranial nerve first you must know what is the function of the specific cranial nerve second if you suspect that your patient is suffering a cranial or lesion you must be able to test the function of the cranial nerve and third you must know what are the major foramina involved in the cranial nerves and their branches this ladder May provide a clue as to the possible side of the presence of a tumor or an infection and I cannot stress enough think function when you think about the cranial nerves let's start with the first cranial nerve the olfactory nerve what do we do with this nerve we smell the actual nerves that detect the smell are located at the roof of the nasal cavity it is precisely why your asses stick your nose inside a wine glass project drinking it to discern its bouquet or nose as it is said in the industry if the ediferous molecules do not reach this olfactory epithelium you'll not be able to smell the wine the olfactory cells then Traverse through the equival form plate of the ethmoid bone to end at the olfactory bulb hence there's a direct connection between the olfactory epithelium and the anterior cranial fossa and this has clinical implications trauma to the region can result in tearing of the cranial nerve resulting in anosmia the loss of smell and even more seriously cerebral spinal fluid rhinorrhea examine the drawing to clearly visualize a pathway of how the olfactory nerves reach the olfactory bulb the criboform plate is part of the ethmoid bone that is indicated in the image corporate 4 means Civ and Latin and it's where the olfactory bulb sits hence you can think of the olfactory nerves as microscopic structures percolating through the holes of the criboform plate to reach the olfactory epithelium and by the way ethmoid also means sieve in Latin using our three-part scheme of what we need to know about each cranial nerve we now know what the olfactory nerve does what are the major foramina involved and now we need to discuss how we test for its function and here it is we simply ask patients to see they can smell common everyday objects loss of smell has many causes and may even be congenital before leaving the topic of smell you may have heard that one of the early symptoms exhibited by covid-19 patients is anosmia or partial loss of the sense of smell often accompanied by changes in taste in the recent study published by the Journal of neuroradiology the virus appears to damage the olfactory bulbs by causing micro pleading in this area shown in this image is what micro pleading will look like in the area of the olfactory bulb when examined using Mr Imaging we now move to the cranial nerve to the optic nerve some anatomical details are described here in the text what do we do with this nerve we see need I say more so it's important imagined your life now without a vision will you be here at Medical School in reality the optic nerve is not a true cranial herb it is an outpocketing of the central nervous system but eliminating it now from the list of cranial nerves would ruin the mnemonic you will spend more time studying the visual pathway in Neuroscience here let's just describe the basic pathway of how we see I have drawn an axial section of the head at the level the optic nerve let me put in some labels for orientation the retina is found at the back of the eyeball and initially collects the information we see the information then Travels by way of the optic nerve cranial nerve 2. with respect to the information we gained via our eyes it will cross over at the optic chiasum that is the right eye will send information to the left side of the brain and vice versa the visual information leaving the optic chiasm will then enter an optic tract and will ultimately end up at the visual cortices of the occipital lobes now let's be a little bit more specific and follow array of light that enters our retina that has arrived there from our temporal field of vision here it is from the left eye note how it strikes a medial aspect of the retina travels to the optic nerve then crosses over to the contralateral optic tract and here it is from the right eye it follows a similar path but to the opposite side now let's see what happens when a ray of light strikes a lateral retina on the left eye and the right eye the light rays that strike the lateral retina does not cross over via the optic chiasma why does crossing over occur apparently crossing over is required for binocular vision and allows for depth of field the temporal side fibers are uncrossed and the fibers from the right half of both retinas form the right optic tract fibers from the left half of both retinas form the left optic tracts you'll learn much more about the visual fields in Neuroscience for Now understand that the visual fields are complicated testing of the nerve of course is straightforward can you see but it turns out there's more to it than that let's just look at a quick example of how we test Vision to appreciate that it can be quite complicated when you shine a light into someone's pupil the pupil contracts on the ipsilateral eye but at the same time the pupil of the contralateral eye contracts also albeit not as completely this is described as both pupils demonstrating consensual contraction and is the expected outcome of shining the light into one eye based on the previous discussion of how light rays cross over from one visual field to the other at the optic chiasma that perhaps the efferent light pathway that is the light shining on the ipsilateral eye and the pharyn pathway listening the pupillary contraction for the contralateral eye May originate within the chiasma but the pathway is far more complicated and involves a midbrain as well as shown in this image the details of these Pathways will be featured in Neuroscience for now just be aware that the pathways are complicated and you'll be expected to know them but in a different course aside from the optic nerve that allows us to see we also need to consider cranial nerves three four and six which are responsible for eye muscles that is these nerves move the eyeball in the direction we wish to see cranial nerve 3 the oculomotor controls all extraocular muscles except the superior Bleak and the lateral rectus cranial nerve for the trochlear supplies a superior Bleak it is called the trochlear because the intertendent of the muscle passes through a connective tissue pulley and pulling latinous citrochlea cranial nerve six the abducens supplies the lateral rectus muscle which abducts the eyeball hence its name and you remember these details by the mnemonic lr6 so4 all others by three finally all these nerves will exit the skull via the superior orbital fissure here's a dissection image of the three nerves after they've entered the orbit and here's the location of the superior orbital fissure it is present within the sphenoid bone shown here in yellow let's not say a few words about the specific nerves that work on the eye muscles and start with the oculomotor in the upper image I'm showing you a dissection of the nerve in the bottom image I show you a drawing representing the nerve the nervous motor to four of six extraocular muscles listed here and what is also interesting that the nerve is responsible for proprioception to these muscles hence we were able to tell where our eyes are looking because of the sensory fibers present in the oculomotor nerve this nerve is also responsible for parasympathetic innervation of the ciliary ganglion now indicated in the dissection and the nerve is also responsible for the motor component for the lens accommodation reflex with changes the shape of the eye so we can see up close the efferent pathways by the optic nerve whereas the efferent pathway is by the oculomotor nerve the nerveal activity muscles inside the eye to alter the focal distance of the eye lesions of the nerve are easily recognized by the condition of ptosis or drooping of the upper eyelid and majorities or dilation of the pupil of the eye also since the pupil cannot be adducted it tends to be abducted by the unopposed action of the lateral rectus a muscle that abducts the eyeball and of course since the lens cannot be accommodated Vision will be impaired we next focus in the trochlear nerve which iterates only one muscle the superior oblique this most difficult nerve to preserve in an orbit dissection the nerve has a long intracranial path to reach the muscle and is readily torn during severe head injuries since the muscle action is to depress and abduct the eyeball in the nervous damage the affected eye will not be able to direct inferol laterally and result in diplopia or double vision when looking downwards I include more details in the slide if you wish to stop the movie and read it now the third nerve in this group The abducens is now labeled in the image the nerve provides motor and aeration to the lateral rectus the nerve can also be torn by severe head injuries and thrombosis in the cavernous sinus when this nerve is damaged diplopia will be present in all directions except when gazing to the side opposite to the lesion as you will learn when we do the cranial Vault lab the cavernous sinus is an area in the middle cranial fossa to which several venous channels drain it is found within the door Mater the tough covering of the brain here we see the location of the cavernous sinus in the middle cranial fossa and the appearance of the sinus in a coronal section now observe the various structures that are at risk of injuring within the cavernous sinus including the internal carotid artery the relationship of the cavernous sinus to the various nerves is more than theoretical although the nurse traveling through the cavernous sinus are difficult to see in a dissection we had skipped the trigeminal nerve but now we discuss it it is the largest cranial nerve it is a significant sensory nerve of the greater part of the face scalp teeth tongue and oral and nasal cavities and it is also motored to the muscle domestication the digastric muscle The myelohyoid Tender Valley palatini and the tensor tympani the nerve has three divisions the ophthalmic the maxillary and the mandibular divisions and note that each division can be described by a specific name for example the ophthalmic division or by denoting it as a branch of the trigeminal nerve V with the subscript of one each division will exit the cranial Vault by three distinct routes now indicated in the image and the three divisions ultimately exit the Bony skull to provide sensory innervation to three pie shaped wedges of the frontal bone the maxilla and the mandible respectively indicated in the slide the mandibular division will also innervate four muscles collectively known as a muscle domestication we will mention a little more about them in a separate lecture clinical testing of the sensory component is straightforward the patient is asked to close their eyes in a soft brush is used to test if they can sense the process it gently touches the three distinct areas served by the trigeminal divisions as shown in the slide the atomic division is also responsible for the sensory component of the corneal reflex if you touch our corneas our eyelids blink the efferent component is via the ophthalmic division the fahren component of the reflex is formed by cranial nerve seven the corneal reflex components are now indicated in the slide the corneal reflex is not the pupillary reflex realize that these reflexes are important to be able to discern in a patient to potentially distinguish between lesions of their cranial nerves trigeminal nerve injuries can result from trauma tumors aneurysms and meningeal infections they manifest in the loss of ability to appreciate soft tactile thermal or painful sensation on the face a most debilitating illness associated with this nerve is known as trigeminal neuralgia particular the illness affects a sensory root of cranial nerve 5 and are characterized by excruciating pain of the areas covered by this nerve pain was so severe that some patients would even commit suicide a virus that afflicts individuals and manifests itself in trigeminal specific fashion is herpesoster commonly known as shingles the virus typically remains latent in the sensory neurons of the trigeminal ganglion with an eruption along V1 the concern is for the cornea finally we cannot forget that the motor component of the trigeminal nerve can also be injured generally as a result of trauma tumors aneurysms or even meningeal infections the injury may result in paralysis the muscles of mastication and the deviation of the mandible will occur towards the side of the lesion and somewhat downwards giving that the muscles of mastication cannot hold up the mandible we'll discuss this further in a later lecture the next nerve up is cranial nerve seven the facial nerve and it is quite a remarkable nerve perhaps my favorite the motor root is motor to the muscles of the face and the scalp including the platysma stapedius stylahyoid and the digastric specifically the posterior belly I know this does not mean much to you now but it will as we continue the head and neck module sensory Roots provide taste fibers for the anterior two-thirds of the tongue by way of the corded tympani nerve and the soft palate if you love chocolate the court of timpani is your friend the nerve carries parasympathetic fibers to the lacrimal submandibular and sublingual gland and glands of nasal and Palatine mucosa that is the nerve helps with salivation but also to express our emotions of both Joy and sadness and finally the nerve enters the internal acoustic meat is in Exorcist call by way of the style of mastoid foramen first let's see where the facial nerve leads the base of the brain and enters the skull and here it is at the internal acoustic meatus along with cranial nerve eight don't expect to be able to identify the nerve here except if you have a view of all cranial nerves at most you can tell where the internal acoustic meatus is located as to where you find this meat is it is on the medial aspect of the petrous part of the temporal bone you need to know this when you're removing the brain from the cadaver and because the tentorium cerebelli attaches to the petrous part of the temporal bone for your convenience I colorize the temporal bone pink I have now labeled the squamous part of the temporal bone put your fingers just above the ears you're now the corresponding location of the skull that is labeled as the squamous part of the temporal bone after showing you where the facial nerve enters the skull let me show you now where it exits the skull on the left I show you your lateral view of the skull and in the middle image I'll show you the base of the skull this view is magnified on the right hand image let's label some landmarks for example the stylus process and the mastoid process go behind your ear and feel the hard bump this is the mastoid process please do not try to feel the stylus process this would hurt the mastoid process develops after we are born by the continuous pull of the sternocleidomastoid on it as we develop the ability to raise our heads think of it as the protector of the facial nerve now look at the frame and just medial to the mastoid process the stalomastoid foramen it is here that the facial nerve exits the skull remember it traverses the petrous part of the temporal bone and now it's outside the skull and now think why an infection of the mastoid process may be dilitaries to the facial nerve there are sinuses within the mastoid process and these can become infected from such procedures as inserting a non-sterile trocar to pierce the Pina of the ear mastoid sinus infections are notoriously difficult to treat and may require the bereavement of the infection with Insidious consequences for the facial nerve and we will actually look for the Stylo message foramen just deep to the large salivary gland the parotid gland as shown in this image when we look for the facial nerve when it exits the skull what does this nerve do it sends branches to the muscles of facial expression all of them no exceptions you want to show emotions you need this nerve you want to close your eyes you need this nerve you want to keep from drooling you need this nerve we'll go into detail later how these muscles all work on your face to control these activities but in addition to the motor components to the muscles of facial expression a small Branch from the nerve the courtesympani exits the nerve and joins up with a branch of the trigeminal nerve the lingual nerve and then proceeds to the anterior two thirds of the tongue to gather the sensation of taste I just love this branch now you know where this nerve excesses skull what it does what else you need to know about it how do you test for it and it's very straightforward you ask your patient to make faces as shown in the slide and also test for tase on the anterior two thirds of the tongue however a word of warning please do not put grits in a northerner and ask them what they taste or put boiled tasteless potatoes on a southerner and ask them what they taste you need to be aware of what people are used to eating if you plan to assess their taste buds me I know very well the curly mint you need for the Cuban mojito versus The Peppermint of the mint julep let's just say I've had very nice culinary experiences in my life let's now mention Bell palsy an Affliction of cranial nerve seven and mention how you would discern such an Affliction imagine a virus that damages your cranial nerve seven how will your face look if now the muscles of facial expression on one side of your face become totally flaccid can you tell in this person which side of the face is suffering from Bell palsy were you correct his right side of the face was afflicted stop the video and read the text for more information regarding Bell palsy and specifically think back to the corneal reflex and understand why Bell palsy can be quite deleterious to the well-being of a healthy individual if you lose your ability to Blink a result of Bell palsy you lose the ability to keep your cornea moist and it can become dry and brittle and lead to infections and even loss of the cornea indeed one of the major complications of Bell palsy is losing the corneal reflex we now move to cranial nerve eight the vestibular cochlear nerve I will not spend much time on this nerve except to say that we should consider it as two separate nerves functionally but anatomically it is described as a single nerve we use this nerve to both maintain balance into here rock and roll of course and definitely classical music but why would anyone want to damage their ears with country music is beyond me losing one's hearing however has been considered a major disadvantage historically and for years it was not possible to determine if the hearing loss was permanent or transient there's a simple test that one can do using a tuning fork to discern whether hearing loss is likely to be permanent or amenable to treatment if a vibrating tuning fork is placed near the ear and the patient cannot detect sound they are considered deaf however this test cannot determine how it reaches the loss of hearing is by placing a vibrating tuning fork on the mastoid process of a deaf individual however and asking them if they sense sensation as shown on the left panel will allow the clinician to determine if hearing loss is due to sensory neural laws that is loss of the nerve or if the deafness can be due to less egregious causes if the nervous present of vibrating tuning force your elicit simulation of the sensory cortex and raise hope for hearing recovery we now move to cranial nerves 9 10 and 11. the glossopharyngeal the vagus and the spinal accessory and these nerves gave Galen a bit of a difficult time he thought they were all a single nerve the three nerves exit the skull via the jugular foramen so that answers one objective for each of the three nerves what do they do well this gets a bit complicated looking at the glossopharyngeal nerve this nerve is sensory motor and provides parasympathetic innervation to the parotid gland we will spend specific time on this nerve later in a lecture so for now let's just remember that the glossopharyngeal nerve is a mixed nerve that has both motor and sensory functions let's look more specifically at the glossopharyngeal nerve after the nerve acts as the jugular foramen it sends out several branches one is a carotid brand to the carotid sinus in the Carotid body these are considered visceral sensory branches and are responsible for detecting blood pressure and oxygen tension respectively in a much larger Branch one known as a pharyngeal branch in addition After exiting the jugular foramen the glossopharyngeal nerve will send a branch back into the mastoid process the tympanic nerve and this nerve will ultimately connect at a plexus and emerge as the Lesser petrosal nerve that will provide parasympathetic innervation by way of the otocaine to the parotic gland don't worry about these details at this time we will review this pathway again several times during the course in this second drawing of the glossopharyngeal nerve we can actually see the pathway by which the parotid gland is innervated we'll discuss this pathway in more detail later in the lecture and again in other lectures what I want you to focus now is on the pharyngeal branch this Branch would be motor to one muscle the style of oranges and the pharyngeal constrictors as well as some branches to the posterior one-third of the tongue these branches will be responsible for both taste and general sensation overall a lot of details but bear with me we will review these Concepts again and again during the module I will tell you however that it is very easy to test whether this Nerf is functional simply by checking for the gag reflex if you touch the anterior aspect of the tongue it is unlikely that your patient will gag if you touch the posterior one third of the tongue however and cranial nerve 9 is functioning your patient will gag I will mention though that this nerve is rarely injured except an individuals who exhibit an exceptionally long stylus process in a an x-ray image of an individual with exceptionally long styloid processes shown and on the right the patient is shown mid procedure during the solidectomy in these individuals the stylus process can be damaged due to trauma and because the glossopharyngeal nerve is near the stylus process the different functions controlled by this nerve will be impaired this is a very rare condition difficult to diagnose And yet when it is people immediately realize that if they had simply remember their basic anatomy the impacted symptoms would have readily led to the cause next we describe the vagus nerve the most complicated of all cranial nerves it helps control the digestive tract basically from its origin to almost its termination and in between it controls our vocal cords heart rate respiration and digestion let's just say we can spend a lifetime studying this nerve and perhaps not reach a full understanding of all that it does but what do we know about this nerve and what does it do in the head and neck let me summarize a few points of interest using this drawing it emerges from the jugular foramen and descends within the Carotid sheath behind in between the internal jugular vein and the internal common carotid arteries from Superior to inferior its branches are as follows the auricular this nerve enters the mastoid on its lateral wall of the jugular foramen the auricular provides General sensory to the Oracle the external acoustic meatus and the tympanic membrane do you want to know why some people experience taste when they hear music this is the nerve that does that the next branch is to the pharyngeal this Branch contributes to the pharyngeal plexus and provides motor innervation to muscles of the pharynx and palate specifically to the levator Valley palatini it is the reason you're asked to say ah when you visit the doctor the superior laryngeal nerve is the next Branch it descends lateral to the pharynx and then divides into the internal laryngeal and the external laryngeal nerves posterior superior to the tip of the greater Horn of the hyoid medial to the external carotid artery the internal laryngeal nerve penetrates the thyroid membrane and provides steneral sensory innervation to the mucosa of the larynx and pharynx in general sensory and taste innervation to the very posterior part of the tongue and epiglottis this is the nerve that stimulated when you feel like coughing the external laryngeal nerve is motor to one muscle the cricothyroid muscle the muscle that allows you to sing falsetto if you can finally we get to the recurrent laryngeal nerves the right and left recurrent laryngeal nerves loop posteriorly around the right subclaving artery in aortic Arch respectively the Ascend in the grooves between the trachea and esophagus on their respective sides as they send posterior to the low to the thyroid gland they enter the larynx and provide General sensory iteration to the mucosa of the larynx and the pharynx and motor Innovation to all the muscles of the larynx except the cricothyroid I told you the vagus is complicated and this is just in the head and neck the motor component of the Vegas however gives us a way of how to test for its functionality you will learn that the uvula is elevated by a muscle the levator Valley palatini that is innervated by the vagus nerve when you ask your patient to say ah if the vagus component is damaged the uvula will deviate away from The Afflicted side I will mention however that the vagus controls so many bodily functions that if it is damaged movement of the uvula is the least likely of afflictions to be experienced by your patient they're likely in ICU and you have many other worries to think about however I did find an image of a deviated uvula in the literature and I show it to you now I spent nearly 30 years of my academic life and had never seen a deviated uvula until someone posted this image on the web what about cranial nerve 11 it is a motor nerve to the sternocleidomastoid into the trapezius muscle we will see this nerve when we dissect the posterior triangle of the neck and here's an image from our book on the cranial nerves describing the old concept of cranial nerve 11 in its association with the Vegas versus the current interpretation of this relationship previously it was thought that cranial nerve 11 joined the vagus nerve current thinking is that it does not stop the video if you wish to look at the details but the bottom line given that the nerve goes to the sternocleidomastoid and the trapezius muscles testing for this nerve is straightforward ask your patients who shrug their shoulder against pressure have you forgotten the action of the trapezius already remember it is the only muscle that acts on the Upper Limb that is not innervated by the brachial plexus we have now arrived at the last cranial nerve the hypoglossal why do we call it by this name because glosses means tongue in Latin and this is the nerve that is below the tongue and innervates all the muscles of the tongue except one the polypoglossal muscle we will spend more time describing the tongue in a separate lecture but one feature of the hypoglossal nerve that I should mention now is that the nerve fibers that regulate the strap muscles of the neck required for swallowing piggyback onto the hypoglossal nerve again we'll present more details about this relationship in a later lecture but now how do you test for this nerve you ask your patient to protrude their tongue and if the nerve is Afflicted the tongue will deviate to The Afflicted side we'll describe in a later lecture why this is so but also the tongue has intrinsic muscles regulated as well by the hypoglossal nerve if the nerve is damaged the tongue can show the characteristic pattern exhibited in the inside picture I now finish the lecture by briefly discussing the four autonomic ganglia found in the head they include the ciliary ganglion the terrigal Palatine ganglion the submandibular ganglion and the otaganglion ordinary modality will be reaching these autonomic ganglia the answer is here in the Box each ganglia will receive somatic sensory and visceral motor innervation in the form of parasympathetic innervation in addition each gang layer will be associated with sympathetic innervation although not precisely as shown in the image the sympathetic nerve will not specifically travel through the ganglia as indicated in the drawing let's now focus more on the autonomic ganglia and Trace the nerves that serve them we look at the somatic sensory nerves that serve the ganglia indicated by the black line in the image and note that each ganglion is served by a distinct branch of the trigeminal nerve B1 does a ciliary ganglion V2 does a teragopalatine ganglion and V3 does a submandibular and otic ganglia again these are simply somatic sensory nerves in the course right through the ganglia and come out the other side we now examine the parasympathetic contributions to each ganglia by following the red line the ciliary gland is served by the oculomotor nerve the terrigal Palatine gland is served by the facial nerve as is the submandibular gland and the glossopharyngeal nerve thus the otic gland I want to emphasize that these four parasympathetic branches serving the autonomic ganglia are pre-ganglionic they will synaptic the respective ganglia then X along with the corresponding sensory nerve as postganglionic nerves we now finish our discussion of the autonomic ganglia by examining the sympathetic innervation indicated by the blue lines in the drawing and the first thing we note is that all the sympathetic iteration reaching the autonomic ganglia is postganglionic arising from the superior cervical ganglion these postganglionic fibers piggyback onto the external and internal carotid arteries and travel to their respective autonomic ganglia again in contrast to the parasympathetic fiber serving these ganglia the sympathetic fibers are all postganglionic where were the preganglionic fibers coming from from the sympathetic trunk into the thorax I should mention that some of these parasympathetic and sympathetic fibers have individual names the preganglionic fibers from the facial nerve to the tarigopolitan ganglion are called the greater petrosal nerve it will be joined by the sympathetic fibers known as the Deep petrosal nerve and together they have been given the name of the nerve the pterygoid canal or the video nerve the parasympathetic nerve to the otic ganglion is also known as the Lesser petrosal nerve a summary of the autonomic innervation is not presented in this final slide GS refers to General sensory nerves from the trigeminal this now concludes this introductory lecture on the cranial errors and the autonomic ganglia in the head