CN V: Trigeminal

Question 1

What are the 3 divisions of the trigeminal and are they sensory, motor or both?

Answer 1

1. Opthalmic (CN V1)- sensory
2. Maxillary (CN V2)- sensory
3. Mandibular (CN V3)- sensory and motor

Question 2

What nerve innervates the anterior 2/3’s of the tongue?

Answer 2

Lingual nerve of V3.

Question 3

What are the resident components of CN V?

Answer 3

Somatic afferent (sensory)- pain, temp, light touch, pressure, and proprioception of from face.

Motor- muscles of mastication, palate and inferior oral cavity.

Question 4

What are the acquired components of CN V?

Answer 4

Special afferent- taste, sensory of anterior 2/3 of tongue.

Parasympathetic-originate in CN 3, 9 and 7. Salivary and mucosal glands and smooth muscle (spinchter of pupil).

Question 5

Which foramen does V1 travel through?

Answer 5

Superior orbital fissure

Question 6

Which foramen does V2 travel through?

Answer 6

Foramen rotundum

Question 7

Which foramen does V3 travel through?

Answer 7

Foramen Ovale

Question 8

What nerves are present in the cavernous sinus?

Answer 8

Occulomotor (III), Trochlear (IV), Opthalmic (V1), Maxillary (V2), and Abducents (VI).

Question 9

What nerve would be effected first by an infection in the cavernous sinus? What would the symptoms be?

Answer 9

Abducents (VI)- innervates the lateral rectus.

• eye would drift medially.
• patient would have a fever and complain of double vision.

Question 10

What are the four branches off of the Opthalmic V1 division of the trigeminal?

Answer 10

1. Meningeal
2. Lacrimal
3. Frontal
4. Nasociliary

Question 11

What muscles of mastication are innervated by the motor branch of the mandibular branch of CN V?

Answer 11

Masseter, lateral pterygoid, medial pterygoid and temporalis.

Question 12

What oral floor muscles are innervated by V3?

Answer 12

Mylohyoid and anterior digastric.

Question 13

What muscle in the middle ear is innervated by V3?

Answer 13

Tensor tympani

Question 14

What muscle in the palate is innervated by the V3?

Answer 14

Tensor veli palatini

Question 15

Which nerves are post ganglionic parasympathetic neurons from CN V destinations for?

Answer 15

Oculomotor (III), Facial (VII), and glossopharyngeal (IX)

Question 16

Where does CN V originate and in what cranial fossa?

Answer 16

Lateral surface of the pons in the posterior cranial fossa.

Question 17

What structure does the trigeminal ganglion sit it?

Answer 17

Meckels cave in the posterior cranial fossa into the middle cranial fossa.

Question 18

What are all of the muscles innervated by the motor root of CN V?

Answer 18

Masseter, Temporalis, medial and lateral pterygoids, mylohyoid, anterior digastric, tensor tympani, tensor veli palatini.

Question 19

Where does CN V1 provide sensory innervation to?

Answer 19

Orbit, cornea, skin of the bridge of nose, scalp and forehead (upper eyelid and above).

Question 20

What are the 4 branches off of V1 (opthalmic)?

Answer 20

1. Lacrimal
2. Meningeal
3. Frontal
4. Nasociliary

Question 21

Where does CN V2 (maxillary) provide sensory innervation to?

Answer 21

Nasal cavity, paranasal sinuses, palate, maxillary teeth and gums, maxillary face (lower eyelid to upper lip).

Question 22

Where does CN V2 originate?

Answer 22

Trigeminal ganglion in middle cranial fossa.

Question 23

What is the course of V2?

Answer 23

Trigeminal ganglion–> lateral wall of cavernous sinus–> enters pterygopalatine fossa via foramen rotundum then divides into multiple branches.

Question 24

What are the branches off of V2 that we are concerned about for this test?

Answer 24

• Posterior superior alveolar nerve
• Infraorbital nerve
• Middle superior alveolar nerve
• Anterior superior alveolar nerve

Question 25

What foramina does the Posterior superior alveolar nerve travel through and what does it innervate?

Answer 25

Enters through posterior superior alveolar foramen. Innervates maxillary molars 2 and 3, and most of molar 1. Innervates Superior vestibular buccal gingiva.

Question 26

What foramina does the infraorbital nerve travel through and what does it innervate?

Answer 26

Goes through inferior orbital tissue, and emerges from infraobital foramen onto face. - Supplies maxillary teeth, lower eyelid, upper lip, lateral surface of the nose.

Question 27

What are the 2 branches off of the infraorbital nerve that we are concerned about for this test?

Answer 27

1. Middle superior alveolar nerve | 2. Anterior superior alveolar nerve

Question 28

What does the middle superior alveolar nerve provide sensory for?

Answer 28

Maxillary premolars and part of 1st molar. Superior vestibular buccal/labial mucosa Maxillary sinus mucosa

Question 29

What does the anterior superior alveolar nerve provide sensory for?

Answer 29

Maxillary incisors and canines. Superior labial gingiva Maxillary sinus mucosa.

Question 30

Where do the parasympathetic fibers of the submandibular and sublingual glands originate and where do they relay at?

Answer 30

O: CN VII (superior salvitory nucleus) R: Submandibular ganglion

Question 31

Where do the parasympathetic fibers of the lacrimal gland originate and where do they relay at?

Answer 31

O: CN VII (superior salvitory nucleus) R: Pterygopalatine ganglion

Question 32

Where does V3 provide sensory innervation to?

Answer 32

Lower face (bottom lip down) Anterior 2/3 tongue Mandibular teeth Anterolateral scalp

Question 33

Which pharyngeal arch does the V3 provide motor innervation to?

Answer 33

1st pharyngeal arch: muscles of mastication

Question 34

What type of fibers are involved in the parasympathetic aspect of CN VII?

Answer 34

SVE | GSA

Question 35

What type of fiber is SVE?

Answer 35

Special visceral efferent- | Muscles from 2nd pharyngeal arch: muscles of facial expression and scalp, stapedius, stylohyoid, posterior digastric.

Question 36

What type of fiber is GSA?

Answer 36

General somatic afferent- | Auricle (external ear, skin of auditory canal and small patch behind ear, outer surface of tympanic membrane.

Question 37

What type of fiber is involved in the sympathetic sensory aspect of CN VII?

Answer 37

SVA- Special visceral afferent | Gustatory taste fibers, anterior 2/3 of tongue and soft palate.

Question 38

What type of fiber is involved in the sympathetic motor aspect of CN VII?

Answer 38

SA- Somatic afferent | Pain, temperature, light touch, pressure and proprioception from face.

Question 39

Where do sympathetic fibers of CN VII relay?

Answer 39

Sympathetic ALWAYS relay at the Superior Cervical Ganglion!!!!!!!!!!!!!!!

Question 40

How do post ganglionic SYMPATHETIC fibers travel to the head and neck?

Answer 40

Periarteriorally.

Question 41

What would happen if there was injury to distal lingual nerve?

Answer 41

- Lose taste from anterior 2/3 tongue. - Lose saliva from submandibular/sublingual glands. - Lose trigeminal component (no sensation to side of tongue and floor of oral cavity).

Question 42

What would happen if you injured the proximal lingual nerve?

Answer 42

Just lose general sensory (trigeminal component).

Question 43

What would happen if you injured chord tympani near eardrum?

Answer 43

- Lose taste - Lose saliva production - Would NOT LOSE GENERAL SENSATION

Question 44

What are the 4 branches of the facial nerve in the temporal bone and what are their associated fibers?

Answer 44

1. Greater petrosal (SVA, GVE, GVA) 2. Nerve to Stapedius (SVE) 3. Chorda Tympani (SVA GVE, GVA). 4. Sensory fibers from auricular branch of CN X (not important)

Question 45

What is important about branches 5-12 of CN VII that happen after exiting the stylomastoid foramen?

Answer 45

Motor branches for muscles of facial expression.

Question 46

What are the muscle groupings innervated by branches 5-12 of CN VII?

Answer 46

Two Zebras Bit My Coccyx | Temporal, zygomatic, buccal, marginal mandibular, cervical.

Question 47

What would be effected if there was a lesion at the entrance to the internal acoustic meatus?

Answer 47

- Motor paralysis - salivation and taste - Deafness - Lacrimation - vestibular dysfuction (dizziness).

Question 48

What would be effected if you had a lesion at the horizontal facial canal (just past internal auditory meatus)?

Answer 48

- Motor paralysis - Salivation and taste - Disturbances of hearing - Lacrimation - No vestibularcochlear component.

Question 49

What would happen if there was a lesion just inferior to where the greater petrosal nerve is given off?

Answer 49

- Motor paralysis - Salivation and taste - Disturbances of hearing - Still able to produce tears

Question 50

What would be the effects if there was a lesion just inferior to stapedius?

Answer 50

- Peripheral motor facial paralysis. | - Disturbances of salivation and taste.

Question 51

What would be the effects of a lesion at the styloidmastoid foramen?

Answer 51

Peripheral motor facial paralysis. | *** Most common lesion***