Cn 9, 10, 11 Anatomy Exam 5

Front 1

1. What do glossopharyngeal and vagus nerves emerge from?
2. What kinds of fibers comprise CN9 and 10?
3. What is spinal accessory nerve (XI) comprised of?

Back 1

The glossopharyngeal (IX) and vagus (X) nerves emerge from the lateral medulla as several rootlets that coalesce to form their respective nerves (rostral rootlets form CN-IX; caudal rootlets form CN-X).
 Both CN-IX and CN-X are comprised of GSA, GVA, GVE, SVE and SA fibers.
 The spinal accessory nerve (XI) is comprised of fibers from the cervical spinal cord. These fibers, classified as SVE, ascend within the subarachnoid space, enter the cranial cavity through the foramen magnum and course with CN-IX and CN-X to reach the jugular foramen.

Front 2

1. What do glossopharyngeal and vagus nerves emerge from?
2. What kinds of fibers comprise CN9 and 10?
3. What is spinal accessory nerve (XI) comprised of?

Back 2

The glossopharyngeal (IX) and vagus (X) nerves emerge from the lateral medulla as several rootlets that coalesce to form their respective nerves (rostral rootlets form CN-IX; caudal rootlets form CN-X).
 Both CN-IX and CN-X are comprised of GSA, GVA, GVE, SVE and SA fibers.
 The spinal accessory nerve (XI) is comprised of fibers from the cervical spinal cord. These fibers, classified as SVE, ascend within the subarachnoid space, enter the cranial cavity through the foramen magnum and course with CN-IX and CN-X to reach the jugular foramen.

Front 3

Where do CN 9, 10, 11 exit the skull? What part the skull is this?

Back 3

Exit the posterior cranial fossa via jugular foramen

Front 4

1. What does tympanic nerve emerge from?
2. From here, where does it pass through and turn to reenter the skull?
3. Where does it ascend along once it enters the tympanic cavity?
What does it now contribute to?
4. What emerges at the superior aspect?

Back 4

1. emerges from inferior ganglion of CNIX. passes through jugular foramen, but reenters cranial cavity via tympanic canaliculus.
2. In the tympanic cavity now it ascends along the medial wall.
Here, it contributes to tympanic plexus
3. At the superior aspect of tympanic plexus, lessor petrosal nerve emerges

Front 5

Describe all the branches of the glosspharyngeal nerve.

Back 5

1. Nerve to stylopharyngeus: runs along posterior aspect of this muscle and innervates it
2. Carotid branch - goes to carotid body and sinus
3. Pharyngeal branch and plexus - at middle constrictor, GVA joins pharyngeal branches of CNX (GVE, SVE) and post gangl symp (GVE).
4. Tonsilar
5. Lingual

Tonsilar an lingual branches emerge between superior and middle pharyngeal constrictor

branches: No Cheese Please Till Later

Front 6

Describe the course of the lesser petrosal nerve begininng from where it emerges to where it exits

Back 6

1. emerges from tympanic plexus (GVE)
pierces roof of tympanic cavity/floor of middle cranial fossa by transversing hiatus for lesser petrosal nerve.
2. lesser petrosal nerve goes in anteromedial direction to reach foramen ovale
3. From here it reaches otic ganglion

Front 7

What are the 2 branches of the vagus nerve in the jugular fossa?

Back 7

1. meningeal branch - emerges from superior vagal gang., reenters cranial cavity via jug. foramen + distributed to dura in posterior cranial fossa.
2. auricular branch - emerges from superior vagal ganglion and gets fiber from CN9 and CN7. Supplies auricle, EAM, outer surface of tympanic membrane

Front 8

Name the branches of the vagus nerve in the neck

Back 8

 Pharyngeal branch Descends from inferior vagal ganglion to reach the middle pharyngeal constrictor, where its branches to contribute to the pharyngeal plexus (along with CN-IX).
 Superior laryngeal n. Emerges from inferior vagal ganglion and terminates by branching into:
o Internal laryngeal nerve (aka: internal branch of the superior laryngeal n.): pierces thyrohyoid membrane to gain access to the larynx.
o External laryngeal nerve (aka:external
branch of the superior laryngeal n.):
descends to supply the cricothyroid
muscle (also contributes to motor
innervation to the inferior pharyngeal constrictor muscle).

Left recurrent laryngeal nerve Arises from CN-X in the thorax;
courses around the aortic arch.
 Right recurrent laryngeal nerve Arises from CN-X in the neck;
courses around the subclavian artery.
o Both the right and left recurrent laryngeal nerves ascend in the groove between the trachea and esophagus, before reaching the inferior pharyngeal constrictor muscle. As these nerves ascend, the

Front 9

1. What is the auricular branch of (GSA) joined by?
2. What does the auricular branch enter into now?
3. What happens about 4 mm above the styloid mastoid foramen?

Back 9

1. The auricular branch of X (GSA) emerges from the superior vagal ganglion and, almost immediately, is joined by a communicating auricular branch of IX (GSA).
2. The auricular branch of CN-X (now also carrying fibers from IX) courses to the lateral wall of the jugular fossa and enters the mastoid canaliculus.
3.About 4 mm above the stylomastoid foramen the auricular branch of CN-X intersects with the facial nerve in its canal. Here, the auricular branch of X acquires fibers from the facial nerve (VII).

Front 10

1. What's the tympanomastoid fissure?

Back 10

Now carrying GSA fibers from CN-VII and CN-IX, the auricular branch of CN-X traverses the tympanomastoid fissure where it branches to supply the auricle, external acoustic meatus and lateral surface of tympanic membrane.

Front 11

QWhat is CNIX formed by? What do they enter the cranial cavity through, and what do they meet up with?

Back 11

CN-IX is formed by motor fibers from the cervical spinal cord (~C1-C5). These fibers ascend within the sub- arachnoid space, enter the cranial cavity through foramen magnum and course laterally to meet up with CN-IX and -X

Front 12

At the jugular foramen, what does CNXI temporarly unit with?

Back 12

Near the jugular foramen, CN-XI temporarily unites with the caudal rootlet of CN-X. This is a brief union; the caudal rootlet of CN-X leaves CN-XI and joins the main trunk of CN-X.

Front 13

What does CNXI leave the cranial cavit through adn where does this course?

Back 13

CN-XI leaves the cranial cavity via the jugular foramen and course inferiorly to innervate the sternocleidomastoid and
trapezius muscles.