SM_13b: Overview of the Cranial Nerves: IX-X

Question 1

Glossopharyngeal nerve (IX) exits the ___ in the ___

Answer 1

Glossopharyngeal nerve (IX) exits the jugular canal in the posterior cranial fossa

(inferior ganglia of CN IX and X is for special and visceral sensation while superior is for general sensation)

Question 2

Glossopharyngeal nerve (IX) exits the ____ with the ____, ____, and ____

Answer 2

Glossopharyngeal nerve (IX) exits the jugular canal with the vagus nerve (X), spinal accessory nerve (XI), and internal jugular vein

Question 3

Describe the components and branches of the glossopharyngeal nerve (IX)

Answer 3

Components and branches of the glossopharyngeal nerve (IX)

• Visceral sensory to naso- and oropharynx (gag reflex) and middle ear (inferior and superior ganglia)
• Taste to back of tongue (inferior ganglion)
• Branchiomotor to stylopharyngeus muscle
• Parasympathetics to otic ganglion/V3/parotid gland via tympanic, lesser petrosal, and auriculotemporal nerves
• Special sensory to carotid body and sinus (inferior ganglion)

Question 4

Primordium of glossopharyngeal nerve (IX) is ___

Answer 4

Primordium of glossopharyngeal nerve (IX) is pharyngeal arch 3

(tympanic nerve is its pretrematic branch)

Question 5

Roots of the vagus nerve (X) exit the ____ between nerves ____ and ____

Answer 5

Roots of the vagus nerve (X) exit the jugular canal between nerves IX and XI

Question 6

Describe the functions of the vagus nerve

Answer 6

Functions of the vagus nerve

• Branchiomotor to pharynx and larynx: test for soft palate movement (say “ahhh”)
• Visceral sensory to most foregut and midgut (inferior vagal ganglion)
• General sensory to external auditory meatus and posterior fossa dura (superior ganglion)
• A little taste in laryngopharynx (inferior ganglion)
• Special sensory to aortic sinus and body (inferior ganglion)
• Presynaptic parasympathetics

Question 7

Vagus branches in the neck include ____, ____, and ____

Answer 7

Vagus branches in the neck include pharyngeal branch, superior laryngeal, and inferior (recurrent) laryngeal

Question 8

Describe the vagus nerve (X) branches in the neck

Answer 8

Vagus nerve (X) branches in the neck

1. Pharyngeal branch to constrictor and palate muscles (except tensor)
2. Superior laryngeal: splits into: internal laryngeal which is visceral sensory to larynx above vocal cords, external laryngeal which is motor to cricothyroid muscle
3. Inferior (recurrent laryngeal): motor to all other laryngeal muscles and visceral sensory below vocal cords

(superior and inferior laryngeal also have parasympathetics)

Question 9

Pharyngeal branch of vagus nerve goes to ____

Answer 9

Pharyngeal branch of vagus nerve goes to constrictor and palate muscles (except tensor)

Question 10

Superior laryngeal branch of vagus nerve splits into ____ and ____

Answer 10

Superior laryngeal branch of vagus nerve splits into internal laryngeal and external laryngeal

• Internal laryngeal: visceral sensory to larynx above vocal cords, parasympathetic
• External laryngeal: motor to cricothyroid muscle, parasympathetic

Question 11

Inferior (recurrent) laryngeal branch of vagus nerve is ____, ____, and ____

Answer 11

Inferior (recurrent) laryngeal branch of vagus nerve is motor to all other laryngeal muscles, visceral sensory below vocal cord, and parasympathetic

Question 12

Primordium of vagus nerve (X) is ____

Answer 12

Primordium of vagus nerve (X) is pharyngeal arches 4 and 6