Cranial Nerve Overview Dr. Selski

Motor fibers in cranial nerves arise from motor nuclei of the brainstem and can be categorized as branchiomotor (to pharyngeal arch derivatives), somatic motor, and visceromotor (autonomic/parasympathetic). • _______ is a useful category to designate innervation of muscles derived from pharyngeal arches (aka branchial arches in fish). {purely FYI: Historically it was given the admittedly confusing term special visceral efferents (SVE), which will not be emphasized in this course - but you may encounter it in the future - sorry.} **Cranial nerves __, ___, __, and ___ innervate skeletal muscles derived from pharyngeal arches 1, 2, 3, and 4, respectively.** • Somatic motor fibers arise from nuclei composed of typical somatic motor neurons. These are similar to those found in spinal cord _____ horn, and are designated general somatic efferents (GSE). They synapse directly on ______ muscles. **Cranial nerves III, IV, VI, XI and XII make up this category (oculomotor, trochlear, abducens, glossopharyngeal, and hypoglossal).** • Visceral motor fibers in cranial nerves are invariably _______ parasympathetics. They are designated as general visceral efferents (GVE) similar to preganglionic sympathetics in the spinal cord. These fibers arise from preganglionic, parasympathetic nuclei and leave the brainstem as a component of a _____ nerve. The fibers synapse on cells of parasympathetic ganglia in or near the target organs. Postganglionic fibers then innervate smooth muscles or glands. **Only cranial nerves ___, ___, ___, and ____ contain preganglionic parasympathetic fibers.**

Branchiomotor V, VII, IX, X (trigeminal, facial, glossopharyngeal, vagus) ventral skeletal PREGANGLIONIC cranial III, VII, IX and X (3 GFs go to Vegas)

f. CN VI—Abducent nerve. See above

Yeah.

Branches of V2 (continued...) The maxillary nerve also gives off palatine and nasopalatine branches that supply the palate, and parts of the nasal cavity. Two palatine nerves, the greater and lesser, arise from the maxillary nerve and rundown through a bony tunnel. The palatine nerves emerge through the palatine foramen. The palatine nerves provide sensation to the parts of the palate. In addition the greater palatine nerve has nasal branches. Together with nasal branches from the trunk of the maxillary nerve, these supply part of the lining of the nasal cavity. The nasopalatine nerve passes through the sphenopalatine foramen, round the front of the sphenoid sinus, and onto the nasal septum. The nasopalatine nerve supplies the nasal septum, and then passes through the incisive foramen, in the maxilla, to supply the anterior part of the hard palate.* Last of all, the maxillary nerve gives off a zygomatic branch. This divides into the zygomaticofacial and zygomaticotemporal nerves. These pass through the zygomatic bone to supply part of the _____. These will also carry some _________ PARASYMPATHETIC fibres toward the lacrimal gland. *Similarly, the palatine sensory nerves described above also carry postganglionic parasympathetic fibres to the nasal/palate mucosa.* These fibres come from the pterygopalatine ganglion associated with V2, but innervated by PREGANGLIONICS from CN VII via the greater petrosal nerve.

cheek POSTGANGLIONIC!

Parasympathetic (GVE) component of CN III: The *preganglionic* parasympathetic fibers synapse in the _____ ganglion (located just behind the eyeball) and *postganglionic* fibres run to the iris to synapse on smooth muscles that change lens and pupil shape. *The ciliary ganglion is associated with the short ciliary nerves which branch from the nasociliary branch of V1 in the orbit. The short ciliary nerves are GSA, but also carry the GVE *postganglionic* fibres to two muscles: ciliary muscle (for lens accomodation for near vision); and sphinchter pupillae (for constriction of the pupil). Note also that postganglionic sympathetic fibres from superior cervical ganglion join the short ciliary nerve to innervate the dilator pupillae.* d. CN IV—Trochlear nerve. See above.

ciliary

V3 - Mandibular Nerve The mandibular nerve passes downward through the foramen ____. It also gives off a meningeal branch that returns to the interior of the skull via foramen spinosum. The mandibular nerve has both MOTOR and SENSORY branches. Its motor branches go to the muscles of ________ : masseter, temporalis, and the pterygoid muscles. *Small branches supply tensor tympani and tensor veli palatini.* The other branches of the mandibular nerve are almost entirely sensory. The buccal nerve runs downwards and forwards to supply sensation to the ____, both outside and inside. *The auriculotemporal nerve passes deep to the neck of the mandible, and then runs upwards to supply sensation to a region on the side of the head. This leaves two major branches which run downward on the ____ _______ muscle. They're the inferior alveolar nerve, and just in front of it, the lingual nerve. The inferior alveolar nerve follows the medial pterygoid muscle down toward the mandible. It enters the mandible through the mandibular foramen. As it enters the bone, the inferior alveolar nerve lies just behind the lingula. Just before it does so it gives off a mylohyoid branch, which runs downwards a groove to supply the mylohyoid muscle and the anterior belly of the digastric*. Passing along the mandibular canal, the inferior alveolar nerve gives off branches that supply the lower teeth and gums. A large branch, the mental nerve, emerges through the mental foramen. The mental nerve supplies the chin and the lower lip. The lingual nerve passes close to the mandible. Early in its course the *lingual nerve* is JOINED by the *chorda tympani, which is a special branch of the _____ nerve*. *The lingual nerve runs down toward the corner of the medial pterygoid muscle, passing just medial to the buttress of the mandible. The lingual nerve passes forwards along the base of the tongue, giving off branches along its length.* The lingual nerve provides common sensation, and also taste sensation, to the ______ two-thirds of the tongue. The taste fibers that travel in the lingual nerve are carried by the chorda tympani from CN VII. Also associated with the lingual nerve is the submandiblar ganglion which gives rise to __________ PARASYMPATHETICS to the submandibular and sublingual glands (and oral mucosa). The submandibular ganglion itself is innervated by preganglionics from CN VII via the chorda tympani.

ovale mastication cheek medial pterygoid facial (VII) anterior POSTGANGLIONIC!

c. CN III—The third, fourth and sixth cranial nerves: the oculomotor, trochlear, and abducent (III, IV, and VI) are motor nerves. Between them they supply the six muscles that move the eye, and also the levator of the upper lid. *The oculomotor nerve arises between the cerebral _____, the trochlear nerve arises from the back of the _____, and the abducent nerve arises below the pons.* The bony opening that these three nerves pass through is the *superior orbital fissure*, but they enter the dura quite a bit further back. The oculomotor nerve passes through the dura just alongside the posterior _______process. The oculomotor CN III and trochlear CN IV nerves pass forward in the lateral wall of the cavernous sinus with the trigeminal branches, V1 and V2. The abducent nerve, CN VI, lies within the ______ sinus with the internal carotid artery. All three nerves pass forward into the orbit through the superior orbital fissure. The seven muscles in the orbit that these nerves supply are the four rectus muscles, the two oblique muscles, and the levator of the upper eyelid. *The oculomotor nerve supplies five muscles, the trochlear and abducent nerves supply just one muscle each. The oculomotor nerve divides into an upper and lower branch, supplying the _____ ______ _______ and superior rectus muscles and the medial rectus and inferior rectus, and the inferior oblique muscles, respectively.*

peduncles midbrain clinoid cavernous levator palpebrae superioris

Parasympathetic (GVE) component of CN IX: As CN IX emerges from jugular foramen, _________ parasympathetic fibres leave the nerve to go to the ___ ganglion where postganglionic fibres supply the _____ gland. *The course and names of these fibres is complex: The tympanic nerve carries the preganglionic parasympathetic fibres from CN IX back into the temporal bone, where they cross through the middle ear as part of the tympanic plexus. From there they emerge from the temporal bone in the middle cranial fossa as the lesser petrosal nerve which joins V3 through foramen ovale to synapse in the otic ganglion just behind the nerve. Postganglionic fibres follow the auriculotemporal branch of V3 to the parotid gland.*

preganglionic otic parotid

*Parasympathetic (GVE) components* of CN VII are TWO-FOLD: 1) Greater petrosal nerve is ultimately headed toward the ________ ganglion where __________ fibres go to the lacrimal gland *(as well as mucosa of the nasal cavity and palate). The full course of these fibres is complex and involves following branches of V2 and V1.* 2) Chorda tympani, in addition to carrying taste fibres, is carrying ________ parasympathetics to the _______ ganglion where postganglionic fibres supply the submandibular and sublingual glands (as well as mucosa of the lower oral cavity). Chorda tympani emerges from the temporal bone and follows the lingual nerve from V3.

pterygopalatine postganglionic preganglionic submandibular

h. CN VIII—Vestibulocochlear nerve enters the internal auditory meatus, dividing as it does so into the vestibular and cochlear nerves. The two nerves transmit the senses of balance and hearing respectively. The sensory cell bodies are located in the ______ ganglion and cochlear (aka ____) ganglion associated with each nerve.

vestibular spiral

General Functions (cont.) •Cranial nerve VII innervates the muscles of facial expression (and three others). {Branchiomotor to the muscles from pharyngeal arch #___.} However, it conveys other functions: CN VII provides ________, parasympathetic innervation to the lacrimal gland and to the sublingual and submandibular salivary glands. Additionally, sensory fibers in CN VII provide the sense of taste to the ______ 2/3 of the tongue. •Cranial nerve IX has several motor and sensory functions in the head and neck, most of which are difficult to assess clinically: General sensation and taste from the ______ 1/3 of the tongue, general sensation from the upper pharynx (specifically the oropharynx), and Brachiomotor to one muscle in the pharynx (________ m.) It also provides preganglionic parasympathetic control of the *parotid gland* (so parotid gland think IX, but the other glands, think VII). •Cranial nerve X provides ________ parasympathetic innervation to thoracic and abdominal organs. In head/neck it has additional functions: Innervates *all larynx muscles* and *most pharynx muscles.* {Branchiomotor to the muscles from pharyngeal arch #___.} Taste from the "root" of the tongue near epiglottis. General sensation from: larynx, lower pharynx, and small area of external ear. THE LAST 2 CRANIAL NERVES ARE STRICTLY MOTOR. •Cranial nerve XI is strictly motor to the trapezius and sternocleidomastoid muscles. •Cranial nerve XII is strictly motor to the muscles of the tongue.

2 *preganglionic* anterior posterior stylopharyngeus preganglionic 4

Overview: There are 12 pairs of cranial nerves. Each cranial nerve is represented by both a Roman numeral designation (never Arabic!) and a name. The name provides a general description of the function. CN I—Olfactory nerve CN II—Optic nerve CN III—Oculomotor nerve CN IV—Trochlear nerve CN V—Trigeminal nerve CN VI—Abducens nerve CN VII—Facial nerve CN VIII—Vestibulocochlear nerve CN IX—Glossopharyngeal nerve CN X—Vagus nerve CN XI—Spinal accessory nerve CN XII—Hypoglossal nerve Name the 4 nerves with parasympathetic components.

3, 7, 9, 10 (Oculomotor, Facial, Glossopharyngeal, Vagus) Mnemonic: *3* *G*irl *F*riends go to *V*egas

Some Important Learning Objectives: Organize the cranial nerves into categories: 1) Special sensory - ___________________ 2) General sensory - __________________ 3) Motor - ________________ 4) Brachiomotor - _______________ 5) Parasympathetic - _________________ 6) Those that "carry" parasympathetic - ____________ (What's the difference b/w motor and brachiomotor? - Dale) Brachiomotor refers to motor to pharyngeal arch derivatives.

CHECK THESE: Special Sensory: 1, 2, 8 (what about taste?) General sensory: 5, 9, 10 + plus a little bit of 7 which supplies general sensory to part of the external ear Motor: 3, 4, (5), 6, (7), (9), (10), 11, 12 Brachiomotor: just 5, 9 and 10? Parasympathetic: 3, 7, 9, 10

Categories of Cranial Nerves The following is a suggested study strategy for categorizing cranial nerves based on their function or distribution or location. *Sensory* functions of cranial nerves further divide into the special senses, general visceral sensation (aka ____) and general somatic sensation (____). •The special senses include _______, vision, hearing and ______. The cell bodies of the neurons in these senses are *in or near the special sensory apparatus* (i.e., in the olfactory epithelium for CN I, ______ for CN II, and the vestibulocochlear apparatus for CN VIII). • The special sense of taste is typically placed in a separate category. {Historically it was called *special visceral afferents - SVA.*} This function is served by fibers in CN VII, CN IX and CN X (in other words, ______, ________, and _____. The sensory cell bodies are in *peripheral ganglia* associated with those three cranial nerves. The central processes of taste fibers all terminate in the same location in the medulla {the ______ nucleus}.

GVA GSA olfaction balance retina Facial, Glossopharyngeal, Vagus (for TASTE!) solitary

k. CN XI—The accessory nerve passes around the upper end of the ______ jugular vein, then passes downward and backward behind the posterior belly of the digastric. It runs beneath the ________________ muscle. The accessory supplies the sternocleidomastoid muscle, sometimes running deep to it, sometimes through it. Emerging near the posterior border of the sternocleidomastoid, the accessory nerve runs downward and backward across the _____ muscle, and passes beneath the other muscle that it supplies, the trapezius.

INTERNAL (aka IJV or IV) sternocleidomastoid splenius KNOW THE RELATIONSHIP OF SPINAL ACCESSORY TO THESE MUSCLES!!!! Potential test questions or lab IDs! Find a good pic.

l. CN XII—The *hypoglossal nerve* emerges between the ______ carotid artery and ______ jugular vein. It runs downward and forward across the external carotid artery. The hypoglossal nerve supplies *all three extrinsic muscles of the tongue* and the *intrinsic muscles*. Realize that the palatoglossus is a muscle of the palate, thus innervated by CN X; and that the geniohyoid and thyrohyoid muscles are innervated by C1 fibres from cervical plexus that follow CN XII. Similarly, C1 and C2 fibres follow CN XII then form the *______ root* of the ansa cervicalis, which passes down in front of the internal jugular vein. It is joined by a branch from C2 and C3 to form a loop, called the ansa cervicalis. The branches that arise from the ansa cervicalis provide the motor supply to the _______ muscles.

INTERNAL, INTERNAL *superior Infrahyoid (strap)

• General somatic sensation (touch, pain, temperature, etc.) is similar to sensory function in spinal nerves for general somatic afferent neurons (GSA). Mainly, cranial nerves V, IX and X (aka ______, ________ , and ______) contain fibers that convey general somatic sensation. {CN VII is general sensory to only a tiny area of the external ear.} Sensory fibers arise from pseudo-unipolar sensory neuron cell bodies that are in a *peripheral ganglion* associated with that cranial nerves: CN V, CN VII, CN IX and CNX. Each sensory neuron and its peripheral fiber convey only one sensation (e.g. either touch or pain). The central process of all GSA sensory neurons synapses on cells of the "sensory nucleus" of the brainstem {the ______ ______ nucleus}. The cells of the sensory nucleus then relay that information to other areas of the brain. • General ______ sensation (*arterial pressure, gut distension, etc.*) is known as general visceral afferents. The general visceral afferent (GVA) neuron cell bodies are in the ______ peripheral ganglia associated with CN IX and X {which connect centrally to the nucleus of the ______ tract}.

Trigeminal, Glossopharyngeal, and Vagus (for GSA!) trigeminal sensory visceral inferior solitary

The following is a fairly complete list of cranial nerve anatomy and function. Much of it should be review. You will need to know all of this by the end of the class (final exam). Italics (*bold* for our quizlet purposes) note information that will not be covered until the last block; thus you should at least know the information that is not italicized for the next exam. Although this format may be confusing, and the content is daunting, I hope that a comprehensive list will be helpful. a. CN I—Olfactory nerve. The olfactory nerve is extremely short. It consists of numerous axons from the olfactory epithelium neurons in the roof of the nasal cavity. These axons project through the ______ plate (of the ethmoid bone) to *synapse on CNS neurons* in the _____ ____ on the underside of the frontal lobe. {The CNS neurons and tracts of the olfactory tract were historically called CN I; but that designation is archaic and should no longer be used.}

cribiform olfactory bulb

g. CN VII—Facial nerve The vestibulocochlear nerve and the facial nerve pass through the ______ auditory meatus. It's a short tunnel with three openings. The facial nerve passes forwards to enter its own bony tunnel, the facial canal. In the facial canal, the facial nerve has a complex course in the temporal bone, passing round the wall of the tympanic cavity, and coming out behind the _____ process. Entering its canal the facial nerve passes forward briefly, then makes an abrupt turn called the *genu* and passes backward. The ______ ganglion is located there and contains the cell bodies of SENSORY neurons (taste and a small bit of general sensory to the external ear). The facial nerve passes backwards high in the medial wall of the tympanic cavity, above the oval window. It then turns downwards, to emerge at the stylomastoid foramen, just behind the root of the styloid process. On its way through the temporal bone the facial nerve gives off three branches, the *greater petrosal nerve* which is a *preganglionic parasympathetic* branch, a branch in the middle ear to the stapedius muscle, and a special branch, the chorda tympani. The chorda tympani passes upwards on the inside of the tympanic membrane, and leaves the cranium to join the lingual nerve from V3. The main continuation of facial nerve passes through the ____ gland. The posterior auricular branch supplies the occipitalis (and the three auricular muscles). The temporal branches supply the frontalis muscle and upper eye muscles. The _______ branches supply the muscles below the eye, including orbicularis oculi. The buccal branches supply buccinator and orbicularis oris. The marginal mandibular branches, which pass just below the body of the mandible, supply the muscles that move the lower lip. Cervical branches supply the ______. In addition to supplying the muscles of facial expression the facial nerve gives off a branch that supplies the posterior belly of the digastric and the stylohyoid muscles.

internal styloid GENICULATE (duh, cuz it's at the genu formed by the facial nerve, VII). parotid zygomatic platysma

i. CN IX—The glossopharyngeal nerve emerges from the _____ foramen, descends ______ to the internal carotid artery *passing around lateral to it, the between stylohyoid and stylopharyngeus muscles. It enters the wall of the pharynx between the superior and middle constrictor muscles and runs deep to the palatine tonsil in the "tonsilar bed".* The glossopharyngeal nerve is branchiomotor to one muscle, the ____________, and provides sensation, including taste, to the ____ third of the tongue, and also sensation to the back of the oral cavity and the oropharynx. *{Note that in the upper pharynx, there is OVERLAP in the sensory distribution of CN IX and CN V2. Similarly in the lower pharynx there is overlap in sensory distribution of CN IX and CN X.}*

jugular *posterior* stylopharyngeus posterior

Other useful ways to categorize cranial nerves: • Nerves of the ______ foramen: CN IX, X, and XI • **Nerves of the cavernous sinus: CN III, IV, V1, V2, and VI.** Remember, Dr. Rhodes has stressed that the first two things to be injured if the cavernous sinus is lesioned or infected are the *Internal Carotid Artery* and *Abducens (VI)!* • Nerves of the superior orbial fissure: CN III, IV, VI, and V1. • Nerves of the orbit (there are 6): CN II, III, IV, VI, V1 and V2. *Remember that the nerves of the orbit are the same as those of the cavernous sinus, with the addition of II, the optic nerve.* • Nerves of the face: CN VII (____) and CN V (_____). • Nerves of the tongue: CN XII (motor); CN V3 and IX (general _____); CN VII, IX, and X (taste). • Nerves of the pharynx/larynx: CN IX (mainly _____) CN X (mainly _____).

jugular motor, sensory sensory sensory motor (you need a motor vehicle to get to karaoke in Vegas. Think karaoke = pharynx/larynx = Vagus nerve X)

j. CN X—Vagus nerve. The principal role of the vagus is to provide parasympathetic supply to organs throughout the thorax and upper abdomen. Generally it is general sensory and motor supply to the lower pharynx and all of the _____. It is brachiomotor to *all muscles of the larynx and to almost all muscle of the pharynx and palate* (except for the one pharyngeal muscle innervated by IX aka syand the one palate muscle innervated by V3). Small general sensory branches go to the ____ ear (and variably to the dura mater in posterior cranial fossa). The vagus runs down the neck with the internal jugular vein ______ it, and the internal and common carotid arteries IN FRONT of it, all the way down to the superior thoracic aperture. The vagus nerve has important branches in the neck. High in the neck the vagus gives off a pharyngeal branch, and the superior laryngeal nerve. *The _______ branch of the vagus enter the wall of the pharynx. It supplies the superior, middle, and inferior constrictor muscles; all the muscles of the palate except the tensor veli palatini; and the longitudinal muscles of the pharynx except the stylopharyngeus (which is innervated by IX). The superior laryngeal nerve passes downwards and forwards towards the lower pharynx. The superior laryngeal nerve divides into an external branch, and an internal branch. The internal branch enters the wall of the lower pharynx by passing through the ______ membrane. It provides sensation to the lower pharynx, the epiglottis, and the part of the larynx that lies above the vocal folds*. The external branch gives motor supply to the cricothyroid muscle and the inferior constrictor muscle. *VERY IMPORTANT DIFFERENCE!!!!* On the RIGHT, the recurrent laryngeal nerve goes beneath the ________ _____. On the LEFT, the recurrent laryngeal nerve goes beneath the ____ of the aorta. In its upward course it crosses the branches of the inferior thyroid artery, or runs between them. *The recurrent laryngeal nerve gives motor supply to ALL THE MUSCLES OF THE LARYNX, except the cricothyroid. It also provides sensation to the larynx below the vocal folds.*

larynx external BEHIND pharyngeal thyrohyoid subclavian artery arch

b. CN II—Optic nerve. CN II exits the back of the eyeball and then the orbit between the tendons of origin of the _____ muscles. The optic nerves merge to from the optic chiasm. Just beneath the chiasm is the _____ ____ of the pituitary fossa. Strictly speaking the optic nerve isn't a nerve; it is an extension of the brain. The retinal ganglion cell neurons (and all other neurons in the retina) are CNS. The optic nerve and tract is covered throughout its course by extensions of all three meningeal layers, dura, arachnoid and pia. The dura is continuous with the ___ layer of the eyeball, the sclera. The optic chiasm is a cross-over point for optic nerve fibers. The fibers of each nerve that connect to the nasal (aka _____) half of the retina cross over into the opposite optic tract. The fibers that connect to the temporal (lateral) halves of the retinae stay on the ___ side. The optic tract is the continuation of these axons *to the ______ {superior colliculus} and to the adjacent thalamus {lateral geniculate nucleus/body}.*

rectus diaphragma sellae outer *medial* same *midbrain*

Again: The recurrent laryngeal nerve that goes beneath the R subclavian artery is the _____ one. The recurrent laryngeal nerve on the _____ goes beneath the arch of the aorta!

right left

V2 - Maxillary Nerve The maxillary nerve gives rise to a small meningeal branch before passing into foramen _______ to emerge in a space ANTERIOR to the sphenoid bone {deep in the pterygomaxillary fissure behind the lateral pterygoid plate}. As it approaches the maxilla it divides into branches. The main continuing trunk of the nerve is known as the ________ nerve. The infraorbital nerve runs forward into a bony tunnel in the floor of the orbit. It emerges again at the _______ foramen. The infraorbital nerve divides into palpebral, labial and nasal branches. These supply the *lower eyelid, part of the nose and cheek, and the upper lip.* The other branches of the maxillary nerve supply the *upper teeth, the nasal cavity and palate, and the upper part of the cheek*. *Most of them run through tunnels in the bone. Because of this, and because they're small, they're hard to show in a dissection. The upper teeth are supplied by the ____ _______ nerves, posterior and anterior, which together form a LOOP. The posterior superior alveolar nerves (in this case there are two) branch off behind the maxilla, and run down to enter tunnels in the maxilla. The anterior superior alveolar nerve arises from the infraorbital nerve within its tunnel, and runs downwards and forwards within the bone. The superior alveolar nerves, anterior, and posterior, form a loop within the maxilla. From this loop dental and gingival branches arise that supply the upper teeth, and the upper gums.

rotundum infraorbital infraorbital superior alveolar

e. CN V—Trigeminal nerve The fifth cranial nerve, the trigeminal, is the largest of the cranial nerves. It's named from the fact that it has three major branches, the ophthalmic, the maxillary and the mandibular. The main functions of the trigeminal nerve are to provide _______ to the face, the nasal cavity and the oral cavity, and to provide _____ supply to the muscles of _______. The trigeminal nerve emerges from the pons, and passes forwards. All GSA *sensory* neuron cell bodies of the trigeminal nerve are in the trigeminal ganglion (remember sensory ganglia ONLY in the trigeminal ganglion). The openings for the three branches are the superior orbital fissure for the ophthalmic, the foramen _______ for the maxillary, and the foramen ovale for the mandibular.

sensation motor, mastication rotundum (Think Oh Max Man, SRO = Standing Room Only.)

General Functions (NOT a complete list of functions) •Cranial nerves I, II and VIII are strictly ______ nerves. •Cranial nerves III, IV and VI are strictly ______ and control movement of the eyes. CN III also carries *parasympathetic ______ * axons toward the eyeball (iris). •Cranial nerve V is the general sensory nerve to the face. The *sensory* cell bodies are in the ______ ganglion; it lies in the middle cranial fossa in the cavernous sinus. The peripheral processes of trigeminal ganglion cells form three major branches — ophthalmic (V1), maxillary (V2) and mandibular (V3). V3 also innervates the muscles of mastication (and four others). {Branchiomotor to the muscles from pharyngeal arch #___.} CN V is NOT parasympathetic as it leaves the brainstem, but parasympathetic fibers that arise from CNs *III, VII, and IX* join some peripheral branches of the trigeminal nerve to reach their destination.

sensory motor preganglionic trigeminal 1

V1 - Ophthalmic Nerve The first branch of the trigeminal, the ophthalmic nerve, gives rise to the ______ nerve, the largest sensory nerve to the dura mater, then V1 passes forwards through the superior orbital fissure. *As it does so it divides. It gives off the ______ nerve which runs just beneath the roof of the orbit, and divides into cutaneus branches which go to the _____. In addition the ophthalmic nerve gives rise to the _____nerve, which supplies the lacrimal gland and a tiny area of skin on the upper lateral eyelid, and the nasociliary nerve, which gives off one or more ethmoidal nerves and a cutaneous branch, the *infratrochlear* nerve. The ethmoid branches of the nasociliary nerve supply this part of the lining of the nasal cavity. Through long and short ciliary nerves, the nasociliary nerve provides sensation to the eyeball.* The branches of the frontal nerve emerge onto the face around the *orbital margin*, or through openings in it. The branches of the frontal nerve are the supraorbital, and the ________. Through these branches the ophthalmic nerve supplies the forehead, the upper eyelid, and the upper part of the nose. Small branches of the ethmoid nerve extend up through small foramina near the cribriform plate to a small area of dura mater in the anterior cranial fossa.

tentorial frontal, forehead lacrimal supratrochlear