Cranial Nerves II

Question 1

Innervation Chart

Answer 1

Question 2

CN VII Modalities

Answer 2

• Facial nerve
  
  • Visceromotor (GVE)
  • Branchiomotor (SVE)
  • Somatosensory (GSA)
  • Viscerosensory (GVA)
  • Special sensory (SVA)

Question 3

Facial Canal

Answer 3

Between the IAM and stylomastoid foramen

Question 4

CN VII exits the cranial cavity through…

Answer 4

the internal acoustic meatus

Question 5

• Facial canal
  
  • Geniculate ganglion

Answer 5

• contains cell bodies for sensory neurons (1^o GSA/GVA/SVA) in CN VII
  
  • Vestibular nerve (CN VIII)
  • Cochlear nerve (CN XIII)
  • Geniculate ganglion
  • Chorda tympani
  • Cochlea
  • Semicircular canals (vestibular apparatus)
  • Malleus
  • Tympanic membrane
  • Auditory canal

Question 6

CN VII: Visceromotor (GVE)

Answer 6

• Lacrimal gland
• Nasal mucosa
• Sublingual gland
• Submandibular gland
• Functions
  
  • parasympathetic: stimulates productions of tears, mucous, and saliva

Question 7

CN VII: Branchiomotor (SVE)

Answer 7

• Muscles of facial expression
• Stapedius muscle
• Posterior belly of digastric muscle
• Stylohyoid muscle

Question 8

CN VII: Somatosensory (GSA)

Answer 8

External ear (pinna)

Question 9

CN VII: Viscerosensory (GVA)

Answer 9

• Sensation from the mucosal lining of the nasopharynx and soft palate
• Follows the same path as SVA fibers

Question 10

CN VII: Special sensory (SVA)

Answer 10

• taste of anterior 2/3 of tongue
• synapse in geniculate ganglion
• Chorda tympani n.

Question 11

CN VIII

Answer 11

• Vestibulocochlear nerve
• Modalities: SSA
• Sensations of hearing (from cochlea) and balance (from vestibular apparatus)

Question 12

Middle ear function

Answer 12

transmit sounds between tympanic membrane (ear drum) and the cochlea (inner ear); convert mechanical vibrations to pressure waves in cochlear fluid

Question 13

3 ossicles of middle ear

Answer 13

• Malleus (“hammer”): sits on the tympanic membrane
• Incus (“anvil”)
• Stapes (“stirrup”): sits on the oval window of the cochlea

Question 14

Middle ear muscles

Answer 14

• Stapedius m.
  
  • CN VII (SVE)
  • Stabilize stapes
• Tensor tympani m.
  
  • CN V₃ (SVE)
  • Dampens sounds (e.g. chewing sounds)

Question 15

The middle ear connects

Answer 15

• pharynx via the auditory tube
• mastoid air cells via the aditus ad antrum

Question 16

Inner ear

Answer 16

• Cochlea
  
  • spiral shaped organ responsible for hearing
• Vestibular apparatus
  
  • balance and orientation in space
  • semicircular canals: measure head rotations
  • otoliths: measure linear acceleration, contained within utricle and saccule

Question 17

CN IX modalities

Answer 17

• Glossopharyngeal nerve
  
  • Viscermotor (GVE)
  • Branchiomotor (SVE)
  • Somatosensory (GSA)
  • Viscerosensory (GVA)
  • Special sensory (SVA)

Question 18

CN IX: Visceromotor (GVE)

Answer 18

• Parotid gland
• Parasympathetic, stimulates saliva production

Question 19

CN IX: Branchiomotor

Answer 19

Stylopharyngeus m.

Question 20

CN IX: Somatosensory (GSA)

Answer 20

Posterior 1/3 of tongue

Question 21

CN IX: Special Sensory (SVA)

Answer 21

Taste from posterior 1/3 of tongue

Question 22

CN IX: Viscerosensory (GVA)

Answer 22

• Carotid sinus (baroreceptors)
• Carotid body (chemoreceptors)
• Upper pharynx
  
  • Oro- and naso- pharynx
• Middle ear

Question 23

CN X Modalities

Answer 23

• Vagus nerve
  
  • Visceromotor (GVE)
  • Branchiomotor (SVE)
  • Somatosensory (GSA)
  • Viscerosensory (GVA)
  • Special sensory (SVA)

Question 24

CN X: Visceromotor (GVE)

Answer 24

• Mucous membranes
  
  • pharynx
  • larynx
  • trachea
• thoracic organs
  
  • heart and lungs
• abdominal organs
  
  • foregut and midgut

Question 25

CN X: Branchiomotor (SVE)

Answer 25

* Soft palate mm. * Levator veli palatini m. * Palatopharyngeus m. * Palatoglossis m. * Salpingopharyngeus m. * Pharyngeal constrictors * Intrinsic laryngeal muscles (via recurrent laryngeal nerve) * Cricothyroid m. (via external branch od superior laryngeal nerve)

Question 26

CN X: Somatosensory (GSA)

Answer 26

* External ear and canal * Tympanic membrane (external)

Question 27

CN X: Viscerosensory (GVA)

Answer 27

* Inferior pharynx * Laryngopharynx * Larynx * Thoracic organs * heart and lungs * aortic body * Abdominal organs * foregut and midgut

Question 28

CN X: Special sensory (SVA)

Answer 28

* Sense of taste * Root of tongue * Epiglottis

Question 29

CN IX

Answer 29

* Spinal accessory nerve * Two parts: * Cranial part (CN XI_C) * Spinal part (CN XI_S) * Modalities * SVE (CN XI_C) * GSE (CN XI_S)

Question 30

Cranial part of CN XI: Branchiomotor (SVE)

Answer 30

* Accompanies CN X * Motor part of pharyngeal plexus * Musculus uvulae m. * Levator veli palatini m. CN XI_C is functionally (clinically) and often anatomically indistinguishable from CN X

Question 31

Spinal part of CN XI: Somatomotor (GSE)

Answer 31

* Trapezius m. * Sternocleidomastoid m.

Question 32

CN XII Modalities

Answer 32

* Hypoglossal Nerve * Somatomotor (GSE)

Question 33

CN XII: Somatomotor (GSE)

Answer 33

* Extrinsic tongue mm. * Genioglossus m. * Hyoglossus m. * Styloglossus m. * Intrinsic tongue mm.

Question 34

Clinical tests for lower cranial nerves

Answer 34

* Shrug test * elevate shoulders against resistance * Motor: Accessory nerve (CN XI) * structure: trapezius * Head turn * turn head against resistance * motor: accessory nerve (CN XI) * structure: SCM muscle * Tongue protrusion * Motor: * Tongue deviates towards side of lesion * Unopposed genioglossus m. (protracts tongue) * Left hypoglossal nerve lesion * Soft palate- uvula position * left CN X/XI_C lesion (nucleus ambiguus) * uvula deviates away from side of lesion * unopposed levator veli palatini m. (elevates uvula)