Cranial Nerves of face, mastication, and movements of the eye

Question 1

Where do cranial nerves V (trigeminal) and VII (facial) arise from?

Answer 1

the pons

Question 2

Does a sensory or motor root arise from the pons of the brainstem for Trigeminal nerve (V)?

Answer 2

both

Question 3

Where are the sensory bodies of Cranical Nerve V (trigeminal) from the pons located?

Answer 3

the semilunar ganglia located in the cranial cavity (similar to dorsal root ganglion, containing cell bodies of general sensory axons)

Question 4

What does the motor compartment of the trigeminal nerve innervate?

Answer 4

muscles of mastication

Question 5

How many major branches arise from the trigeminal nerve after he sensory trigeminal fanglia? What are they called?

Answer 5

Three- 1) V1 or Opthalmic, 2) V2 or Maxillary, 3) V3 or Mandibular

Question 6

Which branch of the trigeminal nerve is the only branch with a motor component?

Answer 6

mandibular or V3 (motor to the muscles of mastication).

Question 7

Which is the main sensory nerve to the face that brings sensory information from the face to the brainstem?

Answer 7

Cr. V (trigeminal)

Question 8

What are the three nerves that branch off of the opthalmic nerve (V1 of the trigeminal nerve)?

Answer 8

1) frontal– which branches into supratrochlear and supraorbital. Sensation from the skin above the eye and nose. 2) Lacrimal– general sensation to the lacrimal gland (also carries postganglionic parasympathetics from CN VII that synapsed in pterygopalatine gangla). 3)nasociliary nerve– sensation to ethmoid sinuses, upper nose. Long and short ciliary nerves are associated.

Question 9

Describe the maxillary nerve (V2)

Answer 9

There are no branches of V2 to identify in lab except the maxillary nerve (V2), which ends on the face as infraorbital. Supplies general sensation to the skin below the eye– infraorbital nerve. Also supplies upper teeth, lower nasal septum, and lateral nose palate. Part of the meninges.

Question 10

What are the two branches of V3, or the mandibular nerve branch of the trigeminal nerve.

Answer 10

1) inferior alveolar nerve– goes into the mandibular foramen. Sensation to the lower teeth and skin of the lower jaw, where it ends as the mental nerve. Nerve to the mylohyoid is a branch.
2) lingual nerve– general sensation to the anterior two thirds of the tongue– V3. But also carries taste fibers to the anterior two thirds from CN VII. Also preganglionic parasympathetic fibers from CN VII to the submandibular ganglia.

Question 11

Where is the main component of the facial nerve (CN VII) derived from?

Answer 11

facial nucleus in brain stem, which contains somatic motor axons that innervate muscles of facial expression.

Question 12

What does the facial nerve main component contain?

Answer 12

somatic motor axons that innervate muscles of facial expression.

Question 13

What are the muscles that are innervated by the facial nerve?

Answer 13

Obicularis oculi, obicularis oris, buccinator, posterior belly of the digastric, stylohyoid, and the stapedius.

Question 14

Which gland does the facial nerve pass through when it exits the skull?

Answer 14

the parotid gland

Question 15

What causes Bell’s palsy?

Answer 15

lower motor neuron lesion of motor components of the facial nerve.

Question 16

What is Bell’s palsy?

Answer 16

flaccid paralysis on one side of the face.

Question 17

What are the two sources of the facial nerve (CN VII)

Answer 17

facial nucleus and nervous intermedius

Question 18

*What is the significance of the nervous intermedius portion of the facial nerve?

Answer 18

1) taste from anterior two thirds of the tongue, 2) preganglionic parasympathetic fibers to lacrimal gland, mucuous glands of the nose, sublingual and submandibular gland (secretions), 3) general sensation to a small area of the skin near the ear.

Question 19

Axons from the preganglionic parasympathetic neurons in the superior salivatory nucleus synapse in either the ____ or the ____

Answer 19

submandibular ganglion or the pterygopalatine ganglion. These ganglia contain cell bodies of postganglionic parasympathetic neurons.

Question 20

*What glands do the postganglionic parasympathetic axons from the pterygopalatine ganglion stimulate?

Answer 20

lacrimal gland and mucous glands in the nose and palate

Question 21

*what glands do the postganglionic parasympathetic axons from the submandibular ganglion stimulate to secrete?

Answer 21

submandibular and sublingual

Question 22

What nerve is responsible for you sensing irritation to the eye? What is responsible for causing you to blink the eye in response?

Answer 22

Afferent – V1 of trigeminal, nasociliary nerves.

Efferent – facial nerve for orbicularis oculi muscle.

Question 23

When one eye is irritated does just that eye blink?

Answer 23

No– both eyes blink. The irritated eye response is called a direct response, while the other eye blinking is a consensual response.

Question 24

where in the brain stem are the axons that carry the motor information to the muscles of mastication?

Answer 24

masticatory nucleus

Question 25

which branch of the trigeminal nerve is responsible to innervating the muscles of mastication

Answer 25

V3 or the mandibular branch

Question 26

What is the TMJ?

Answer 26

temperomandibular joint-- a modified hinge type of synovial joint between mandibular condyle and mandibular fossa of zygomatic process. An articular fibrocartilage disc separates the condyloid process from the mandibular fossa. There is an atricular tubercle just anterior to the fossa. The movements of the TMJ are rotational (depression and elevation) and translational (protrusion and retraction), and can move the jaw from side to side.

Question 27

What are the ligaments of the TMJ?

Answer 27

1) capsule, 2) lateral temperomandibular ligament. It is part of the capsule and prevents excessive side to the side movements and depression

Question 28

What is the stable position of the TMJ?

Answer 28

elevation

Question 29

Which ligament of the TMJ prevents excessive side to side movements and depression?

Answer 29

lateral temperomandibular

Question 30

Which ligament of the TMJ prevents excessive protrusion and depression?

Answer 30

stylomandibular

Question 31

Which ligament of the TMJ prevents excessive depression?

Answer 31

sphenomandibular

Question 32

What is the difference between an upper motor lesion and lower motor lesion with Bell's Palsy?

Answer 32

Upper motor = opposite side of the damage. DOES NOT affect the forehead. The lesion comes from the pons. Lower motor lesion = affects same side of the nerve damage. The entire side of the face droops.

Question 33

What carries information for taste or special sensation to the anterior two thirds of the tongue to the lingual nerve?

Answer 33

chorda tympani

Question 34

If a bug flies in your eye what nerve carries pain or sensation fibers from the cornea of your eye?

Answer 34

V1 (nasociliary) of the trigeminal nerve.

Question 35

What nerve causes the reflex of you blinking from the bug in your eye?

Answer 35

VII (facial) as reflex.

Question 36

A patient's face droops downward on the left side and she cannot wrinkle the left side of her forehead. A) What structure is affected that would result in these symptoms? B) is this an upper motor or lower motor type lesion?

Answer 36

A) the facial nerve-- motor components, B) lower motor

Question 37

Which two eye muscles are not innervated by the occulomotor nerve (CN III)?

Answer 37

superior oblique and lateral rectus

Question 38

What would happen if there were complete damage to CN III?

Answer 38

1) loss of levator palpebrae, so there would be a droopy eyelid ipsilaterally, 2) only the superior oblique and lateral rectus are in-tact, so the eye would be stuck in the "down-and-out" position. 3) loss of sphincter pupillae (unopposed dilator pupillae innervated by sympathetics) results in dilated pupil and loss of pupillary light reflex in affected eye. 4) loss of ciliary muscle-- no accommodation of lens

Question 39

What is lateral strabismus?

Answer 39

when the eye is stuck in the down and out position (due to damage to CN III -- oculomotor nerve). This results in double vision.

Question 40

What happens if there is partial CN III damage due to compression of CN III against the petrous portion of the temporal bone by intracranial pressure caused by a hematoma?

Answer 40

parasympathetic fibers of CN III are damaged first (b/c they are more superficial). This results in dilated pupil (loss of pupillary light reflex and accomodation). Called internal opthalmoplegia. You could also have external opthalmoplegia, where somatic motor fibers of CN III are damaged by the parasympathetics are intact.

Question 41

What is the acccommodation reflex?

Answer 41

CN II and CN III. Eye focuses on near object sensory signal sent down CN II to the brain and the message is interpreted and motor signal is sent down CN III to the ciliary muscle, which changes the shape of the lens to bring the eye into focus.

Question 42

What is the pupillary light reflex?

Answer 42

CN II and CN III. When you shine a light near the eye a sensory signal is sent down CN II to the brain and the message is interpreted and a motor signal is sent down CN III by parasympathetic fibers via short ciliary nerve to the sphincter pupillae muscle, which constricts the pupil in response to the light.

Question 43

What are the two accessory muscles of mastication?

Answer 43

mylohyoid and anterior digastric

Question 44

What are the muscles of mastication?

Answer 44

lateral pterygoid, temporalis, medial pterygoid, masseter,

Question 45

What innervates the mylohyoid and anterior digastric?

Answer 45

nerve to mylohyoid, motor branch of V3 (mandibular branch of trigeminal nerve)

Question 46

What are the steps of mastication?

Answer 46

First step is to move the mandibular condyle forward onto the articular process of the temporal bone. The lateral pterygoid protracts the mandible. The condyle is depressed (rotation) and then protruded (translation). The second step is to open wider. The mylohyoid and anterior digastric can depress the mandible further. Step 3 is to return to a stable position. In this step the anterior temporalis, masseter, and medal pterygoid elevate the mandible. The posterior temporalis is the retractor. The jaw returns to the stable position in the mandibular fossa.

Question 47

Which step of mastication is unstable? Why? What can result from this?

Answer 47

step 2. The jaw can be dislocated in front ofthe anterior tubercle. The ligaments can become stretched. This could lead to TMJ syndrome, which could be pain and clicking.

Question 48

What is the difference between incisal chewing and side-to-side chewing?

Answer 48

incisal chewing is when the condyles rotate forward on both sides and depress the mandible symmetrically. To return the mandibular condyles rotate and the condyles are elevated. Side to side chewing is when one condyle is forward on an articular tubercle, while the other is not. This is assymetrical.

Question 49

Which nerve exits through the stylomastoid foramen?

Answer 49

the motor portion of the facial nerve (VII)

Question 50

Taste or special sensation of the tongue is innervated by?

Answer 50

CN VII (Facial)

Question 51

Anterior two thirds of the tongue gets general sensation from?

Answer 51

V3 (Lingual) of CN V (Trigeminal)

Question 52

Posterior one third of the tongue gets general sensation and taste from?

Answer 52

CN IX Glossopharyngeal

Question 53

What provides motor innervation to the tongue?

Answer 53

hypoglossal nerve (CN XII). Hypoglossal nerve arises from the medulla. There are two hypoglossal nerves. When the tongue is stuck out, the genioglossus muscles on both sides pull the tongue forward.

Question 54

What happens if there is a lesion to the hypoglossal nerve on one side?

Answer 54

The tip of the tongue will deviate toward the side of the lesion. The genioglossus on the affected side is not working, so it can't pull the tongue forward on that side. Fasciculations and atrophy of the tongue can occur on the side that is deinnervated.

Question 55

How do you check the integrity of the hypoglossal nerve and the medulla?

Answer 55

stick the tongue out. If it deviates towards one side then there is a lesion on that side to the hypoglossal.

Question 56

Which portion of the temporalis is a retractor of the mandible?

Answer 56

posterior

Question 57

What is the innervation of the extraocular muscles of the eye?

Answer 57

LR6SO4AO3. Lateral rectus = CN VI, Superior oblique = CN IV, All others = CN III

Question 58

Which nerve provides motor innervation to the levator palpebral, superior rectus, medial rectus, inferior oblique, and inferior rectus muscles?

Answer 58

occulomotor (CN III)

Question 59

Which motornerves derive from the midbrain?

Answer 59

CN III and CN IV, oculomotor and trochlear.

Question 60

What motor innervation does the trochlear nerve (CN IV) provide?

Answer 60

superior oblique

Question 61

What motor nerve/s derive from the pons?

Answer 61

Abducens (CN VI)

Question 62

What muscle does the abducens (CN VI) provide motor innervation for?

Answer 62

lateral rectus

Question 63

What are the branches of Ci (Opthalmic) nerve?

Answer 63

1) Frontal-- divides into supratrochlear and supraorbital. Lacrimal-- to lacrimal gland. Nasociliary - to the nose, ethmoidal sinuses, and long ciliary branches to the cornea. Corneal reflex.

Question 64

Which nerve innervates levator palpebrae?

Answer 64

CN III (superior division)

Question 65

what would happen to the eye if there were a lesion to CN III?

Answer 65

drooping of eyelid

Question 66

The Z axis of the eyeball has which types of movements?

Answer 66

adduction and abduction (lateral rectus = abduction; medial rectus = adduction)

Question 67

The X axis of the eye has which types of movement?

Answer 67

elevation and depression. The superior rectus elecates and the inferior rectus depresses.

Question 68

The Y axis has which types of movement?

Answer 68

extorsion and intorsion. oblique muscles.

Question 69

What muscles would activate if I were to look to the right?

Answer 69

lateral rectus of right eye abducts while medial rectus of left eye adducts

Question 70

what muscles would be activated if I were to look upward and out?

Answer 70

the inferior oblique is active on the outer eye (up and out). The superior rectus looks up and in for the opposite eye.

Question 71

What muscles would be activated if I were to look downward and out?

Answer 71

The superior oblique would be the prime mover for the outer eye. The inferior rectus would look down and in for the other eye.

Question 72

What muscles are activated to look straight up?

Answer 72

superior rectus and inferior oblique on both eyes

Question 73

What muscles are activated if I were to look straight down?

Answer 73

superior oblique and inferior rectus for both eyes.

Question 74

What is diplopia?

Answer 74

double vision. common symptom for eye muscle problems.

Question 75

What is strabismus?

Answer 75

can be lateral or medial. The eye cannot move to the side of the lesion. It can be pulled in the opposite direction by the muscle that is not lesioned.

Question 76

What is ptosis?

Answer 76

drooping of upper eyelid

Question 77

What would cause loss of constriction or accomodation?

Answer 77

loss of parasympathetic fibers with the oculomotor nerve (III)

Question 78

Lesion of what nerve would cause lateral strabismus?

Answer 78

oculomotor

Question 79

Lesion of what nerve would cause double vision?

Answer 79

oculomotor (III), trochlear (IV), or abducens (VI)

Question 80

What are the five branches of facial nerve that innervate muscles of facial expession?

Answer 80

Tell Ziggy Bob Marley Called: Temporal, Zygomatic, Buccal, Mandibular, Cervical

Question 81

Loss of corda tympani results in?

Answer 81

loss of taste to anterior 2/3 of the tongue.

Question 82

Which nerve is vulnerable to damage during neck surgeries?

Answer 82

Accessory XI

Question 83

Summarize the cranial nerve related to the tongue

Answer 83

1) anterior two thirds of the tongue: general sensation is CN V V3 lingual branch, special sensation-- taste is from CN VII chorda tympani branch. 2) posterior 1/3 of tongue. General sensation is the CN IX glossopharyngeal nerve. The special sensation is CN IX glossopharyngeal nerve.

Question 84

The hypoglossal nerve (XII) arises from?

Answer 84

the medulla

Question 85

What are the branches of the opthalmic nerve?

Answer 85

Frontal, lacrimal, and nasociliary

Question 86

What does the opthalmic nerve (V1) do?

Answer 86

sensory to the orbit, frontal scalp, upper eyelids, cornea, and ethmoidal air sinuses.

Question 87

Describe the corneal reflex?

Answer 87

Corneal reflex = VI brings sensory information from cornea to brain via long ciliary nerves. The facial nerve (VII) innervates the obicularis occuli, closing the eyelids, and the preganglionic parasympathetic axons oto the pterygopalatine ganglion that leads to tearing.

Question 88

In strabismus is the eye pulls ipsilaterally or contralaterally with regards to the injured muscle?

Answer 88

eye is pulled in opposite direction of injured muscle (contralaterally)

Question 89

If a patient has to tilt her head downward to use the unaffected side to see downward, what nerve is likely lesioned?

Answer 89

Trochlear nerve (CN IV) because the superior oblique is affected, leading to a weak downward gaze.

Question 90

If the patient cannot move the affected eye outward, what nerve is likely lesioned and why?

Answer 90

CN VI (Abducens) because the lateral rectus is affected. This is medial strabismus-- the eye stays fixed because of tension generated by the medial rectus.