Cranial Nerves to the face

Question 1

Trigenimal nerve: CN V

Answer 1

has a sensory and motor root that arise from the PONS brainstem.

sensory: in the semilynar ganglia located in the cranial cavity
motor: innervation for themuscles of mastication 3 major branchesafter the sensory trigeminal ganglia:
1. opthalmic, V1
2. Maxillary V2
3. Mandibular V3

Question 2

opthalmic nerve

Answer 2

V1: goes through the superior orbital fissure and branches off into 3 other nerves.

1. frontal nerve: divides into supraorbital and supratrochlear nerves. General sensation to the forehead
2. Lacrimal nerve: goes to lacrimal gland, carries parasympathetic fibers from VII that are secretomotor to the gland
3. nasociliary nerve: sensation to the ethmoidsinuses and part of the lining of the nose. Long and short ciliary nerves. Sensory to the upper part of the nasal septum and lateral wall of the nose.

also supplies general sensation of the cornea to the eye

Question 3

Maxillary Nerve

Answer 3

V2: second branch of trigem. Goes thru foramen rotundum in the skull

runs under the eye and exits the skull through the infraorbital foramen. Then provides general sensation to the skin of the face below the orbit and the nose

infraorbital nerve: sensory from the upper teeth, lower eyelid, maxillary sinueses, upper lip, lateral lower nose and septum, and palate

part of the dura in the middle cranial fossa

Question 4

Mandibular Nerve

Answer 4

V3: comes from the cranial cavity through the foramen ovale and into the infratemporal fossa

Branches:

1. inferior alveolar: branches off main mandibular nerve, goes into mandibular foramen, sensation to lower teeth, passes through mandible and exits out through the mental foramen where it becomes the mental nerve, sensation to theskin of the lower jaw/face
2. lingual nerve: branches from mandibular in infratemporal fossa. General sensation to the anterior 2/3 of the tongue

chorda typani: carries preganglionic sympathetic nerve fibers from CNVII that go into the lingual nerve and then to the submandibular ganglia. synapse with post ganglionic fibers and are secretomotor to the submandibular and sublinqual salivary glands

also provides sensation to the cheek, lower lip oral cavity, temporal region of the face, in front of the ear and meningeal branch that could lead to headaches

only branch of the trigem with a motor component, motor to muscles of mastication

Question 5

3 muscles of facial expression

Answer 5

1. obilcularis oculi: closes eye
2. obilcularis oris: helps to close the mouth
3. buccinator: pulls cheek against teeth, puckering

Question 6

2 parts of the facial nerve

Answer 6

come from the pons of the brainstem:

1. motor root: motor to muscles of facial expression
2. intermediate nerve, “nervous intermedius”: carries taste, somatic sensory and parasympathetic fibers

Question 7

path of the facial nerve

Answer 7

pons –> internal acoustic meatus (forms geniculate [sensory] ganglia)–> behind ear to facial canal –> stylomastoid foramen–> 5 branches–>thru parotid–V innervates facial expression muscles

1. temporal
2. zygomatic
3. buchacal
4. mandibular
5. cervial

Question 8

geniculate ganglia

Answer 8

sensory ganglia that is formed by a bend in the facial nerve

the greater petrosal nerve runs forward from the ganglia and provides preganglionic parasymp. fibers to the pterygopalatine ganglia. After syndapse these fibers get onto the lacrimal gland and nerbe and are secretomotor for tears. Some taste fibers come from CNVII and fo to the upper palate

Question 9

parasympathetic parts for the facial from the intermediate nerve

Answer 9

motor to the lacrimal, sublingual, and submandibular glands

Question 10

taste or special senation

Answer 10

anterior 2/3 of the tongue carried by chorda tympani to lingual nerve

Question 11

other muscles with motor from facial

Answer 11

post belly of digastric

stylohyoid

stapedius

Question 12

Corneal Reflex. Whats sensory? Whats motor?

Answer 12

sensory/afferent: irritation carried on V1, nasociliary nerves

motor/efferent: facial to obicularis oculi

Question 13

You are running a ten mile loop and a bug flies in your eye. What happens? Do you blink? What nerve carries pain or sensation fibers from the cornea of your eye?

Answer 13

Both eyes are supposed to blink. Irritated eye response is a direct response where the other eye is a consentual response.

opthalmic n.

Question 14

Bell’s palsy

Answer 14

injury to the facial nerve or its branches which produces paralysis of some of all of the facial muscles on affected side.

symptoms:

• droopy eyelid, dry eye, excessive tears
• facial paralysis, twitching or weakness
• drooping cornor of mouth, dry mouth, impaired taste