Cranial nn. VII - XII details

Question 1

What are the cranial nuclei of the seventh cranial nerve?

Quality of fibers?

Answer 1

n. facialis

4 nuclei:

• ncl. n. facialis = SVM
• ncl. salivatorius sup. = GVM
• ncll. tractus solitarius = SVS
• ncl. spinalis n. trigemini = GSS

Question 2

Differentiate btw the 2 parts of n. VII and its type of fibers.

Answer 2

• facialis part = SVM, GSS
• n. intermedius = GVM, SVS

Question 3

Describe the pathway of n. VII.

Answer 3

n. facialis

1. exits brain seperately at angulus pontocerebellaris
2. canalis n. facialis
   
   1. enters through porus acusticus int.
   2. forms geniculum, receives fibers from ggl. geniculi, giving off 3 branches
   3. exits in foramen stylomastoideum, give off 3 mm. branches
3. forms motor plexus intraparotideus at gl. parotis

_{1 = geniculum + ggl. gen., 2 = for. stylom., 3 = at gl. par.}

Question 4

List all branches of n. VII.

Where do they originate?

Answer 4

in order, 7 branches:

• n. petrosus maj.: in geniculum n. VII
• n. stapedius: in desc. part of canalis n. VII
• chorda tympani: before leaving canalis n. VII
• mm. branches
  
  • n. auricularis post.: at for. stylomastoideum
  • r. digastricus, stylohyoideus: at for. stylom.
  • plexus intraparotideus: at gl. parotis

_{1 = gen., 2 = for. stylom., 3 = plexus intrap., 9 = n. auric. post., 10 = n. petr. maj., 12 = chorda tymp.}

Question 5

Describe the various functions of the facial part of n. VII.

Refer to the responsible branches and quality of fibers.

Answer 5

SVM

• n. auricularis post. → mm. of ext. ear
• plexus intraparotideus → mm. of facial expression
• r. digastricus → venter post. m. digastrici
• r. stylohyoideus → m. stylohyoideus
• n. stapedius → m. stapedius

GSS

• n. auricularis post. → skin of post. ear

Question 6

Which branches of n. VII are considered part of n. intermedius?

Describe their function, also refer to the quality of fibers.

Answer 6

SVS = taste

• chorda tympani → ant. 2/3 of tongue

​parasymp. GVM

• chorda tympani → gl. subm., subl., gl. lingualis ant.
• n. petrosus maj. → gl. lacrimalis

Question 7

Describe the pathway of n. petrosus maj.
N. facialis or n. intermedius?

Function?

Answer 7

branch of n. intermedius

1. preganglionic parasymp. fibers from NTS branch off at geniculum n. VII into hiatus canalis n. petrosi maj.
2. run through for. lacerum and
3. canalis pterygoideus to form together w/ n. petrosus prof. n. canalis pterygoidei
4. terminate in ggl. pterygopalatinum

​→ eventually fibers carried via branches of n. V to gl. lacrimalis (cf. own card)

_{3 = NTS, 4 = n. VII, 6 = n. petr. maj., 7 = ggl. pterygop., 9 = gl. lacr., 10 = r. comm. of n. zyg., 11 = n. lacr. (V1)}

Question 8

Describe the pathway of n. stapedius.
N. facialis or n. intermedius?

Function?

Answer 8

branch of n. facialis

branches off in des. part of canalis n. facialis to

→ m. stapedius (sound adaptation)

Question 9

Describe the pathway of chorda tympani.
N. facialis or n. intermedius?

Function?

Answer 9

branch of n. intermedius

1. SVS fibers (from NTS), GVM fibers (from ncl. sal. sup.) branch off from n. facialis before leaving canalis n. facialis
2. in plica malleolaris through tymp. cavity
3. exits skull through fissura petrotympanica
4. fibers run together w/ n. lingualis​

→ GVM fibers to ggl. submandibulare, SVS fibers continue to ant. 2/3 of tongue

_{2 = ncl. sal. sup., 3 = NTS, 4 = n. fac., 5 = ggl. gen., 12 = chorda ty., 13 = n. ling., 14 = ggl. subm., 17 = taste fibers}

Question 10

Where can ggl. geniculi be found?

Function?

Answer 10

at geniculum in canalis n. facialis

• pseudounipolar SVS perikarya for taste innervation of ant. 2/3 of tongue _{(NTS → chorda tympani)}
• pseudounipolar GSS perikarya for sensory innervation of post. ear _{(ncl. spinalis n. V → n. auricularis post.)}

_{3 = NTS, 4 = n. facialis, 5 = ggl. gen., 12 = chorda ty., 17 = taste fibers}

Question 11

Where does n. auricularis post. branch off from n. VII?

Function?

Answer 11

first branch of n. VII at foramen stylomastoideum

• SVM: venter occ. m occipitofrontalis + mm. of ear
• GSS: post. ear

Question 12

Where can plexus intraparotideus be found?

Branches?

Function?

Answer 12

mm. branches of n. facialis exiting gl. parotis
⇒ mm. of facial expression

2 main branches:

• n. temporofacialis
  →rr. temporales, zygomatici
  → rr. buccales → m. buccinator
• n. cervicofacialis
  → r. marginalis mandibulae
  → r. colli (part of ansa cerv. superf.) → plathysma

_{​3 = enters gl. par., 4 = rr. temp., 5 = rr. zyg., 6 = rr. bucc., 7 = r. marg. mand., 8 = r. colli}

Question 13

Where can ggl. pterygopalatinum be found?

Which nerves only cross it w/o synapsing?
Target organs?

Answer 13

in fossa pterygopalatina

• symp. root:
• *n. petrosus prof.** (plexus car. int.) → lacrimal gland
• sensory root:
• *rr. ganglionares** (V/3) → mucosa of nasopharynx, palate, nose

₇

Question 14

Where does ggl. pterygopalatinum receive its preganglionic fibers from (nucleus + nerve)?

Where to (nerve + target organ)?

Answer 14

GVM fibers from ncl. salivatorius sup.

preganglionic parasymp. fibers:

• n. petrosus maj. (VII)

postganglionic parasymp. fibers:

• rr. ganglionares, n. zygomaticus (V/2), n. lacrimalis (V/1) → lacrimal gland
• nn. nasales post. (V/2) → nasal glands
• nn. palatini (V/2) → palatine glands

Question 15

Where can ggl. submandibulare be found?

Which nerves only cross it w/o synapsing?
Target organs?

Answer 15

between gl. lingualis and submandibularis

• symp. root:
• *plexus car. ext.** along a. facialis
• sensory root:
  rr. ganglionares of n. lingualis

⇒ gl. subm., subl., lingualis ant.

_{14 = ggl. subm., 15 = gl. subm., 16 = gl. subli.}

Question 16

Where does ggl. submandibulare receive its preganglionic fibers from (nucleus + nerve)?

Where to (nerve + target organ)?

Answer 16

GVM fibers from ncl. salivatorius sup.

preganglionic parasymp. fibers:

• chorda tympani (VII), n. lingualis (V/3)

postganglionic parasymp. fibers:

• rr. glandulares → gl. subm., gl. subl
• n. lingualis (V/3) → gll. lingualis ant. (NUHN-BLANDIN)

_{12 = chorda tymp., 14 = ggl. subm., 15 = gl. subm., 16 = gl. subli.}

Question 17

Where does the eighth cranial nerve originate?

Quality of fibers?

Function?

Answer 17

n. vestibulocochlearis (SSS)

2 branches:

• n. cochlearis
• n. vestibularis

→ auditory perception + position, locomotion

Question 18

Describe the pathway of n. VIII.

Answer 18

1. n. cochlearis originates from ggl. cochleare
   * *n. vestibularis** originates from ggl. vestibulare
2. both nerves fuse to n. VIII in meatus acusticus int., exit at porus ac. int.
3. enter brain in angulus pontocerebellaris
4. terminate seperately in ncl. cochleares, vestibulares

​_{5 = n. vest., 6 = ggl. vest., 8 = n. cochl., 9 = ggl. cochl., 10 = porus ac. int., 11 = ang. pontoc.}

Question 19

What is special about ggl. cochleare, vestibulare?

Answer 19

both contain perikarya of bipolar neurons

• ggl. cochleare:
  organ of Corti → n. cochlearis
• ggl. vestibulare:
  semicircular ducts, sacculus, utriculus → n. vestibularis

_{​2 = semic. ducts, 3 = sacc., 4 = utr., 5 = n. vest., 6 = ggl. vest., 7 = cochlea, 8 = n. coch., 9 = ggl. cochl.}

Question 20

List the nuclei of n. IX.

Quality of fibers?

Answer 20

n. glossopharyngeus

5 nuclei:

• ncl. ambiguus = SVM
• ncl. salivatorius inf. = parasymp. GVM
• ncll. tractus solitarius = SVS
• ncl. spinalis n. trigemini = GSS
• ala cinerea lat. = GVS

Question 21

Describe the pathway of n. IX.

General function?

Answer 21

n. glossopharyngeus

1. exits brainstem in sulcus paraolivaris lat.
2. runs caudally through foramen jugulare, forming:
   
   • ganglion sup. n. IX
   • ganglion inf. n. IX
3. then btw m. stylopharyngeus, m. styloglossus to root of tongue → terminal branches

→ sensory innervation of tongue, motor innervation of pharynx

_{1 = for. jug., 2 = ggl. sup., 3 = ggl. inf., 7 = m. stylogl., 8 = m. styloph.}

Question 22

Where can ggl. superius of n. IX be found?

What is its function?

Another name?

Answer 22

• *= Ehrenritter’s ganglion**
  sup. to foramen jugulare

contains: pseudounipolar GSS perikarya for sensory innervation of post. 1/3 of tongue, parts of pharynx, meningei, auditory tube, tonsills, etc. (ncl. spinalis n. V → various)

Question 23

Where can ggl. inferius of n. IX be found?

Another name?

Function?

Answer 23

= ganglion petrosum
in fossula petrosa

contains:

• pseudounipolar GVS perikary for glomus caroticum (ala cinerea lat → Hering’s nerve)
• preganglionic SVS perikary for taste innervation of post. 1/3 of tongue (NTS → rr. linguales)

Question 24

List all branches of n. IX.

Answer 24

in order

• n. tympanicus
• 1 muscular branch
  
  • r. m. stylopharyngei
• 3 (types of) sensory branches
  
  • rr. pharyngei
  • rr. linguales
  • r. sinus carotici

_{​4 = n. tymp., 9 = rr. pharyngei, 10 = r. sinus car.}

Question 25

Describe the pathway of n. tympanicus. Function (quality of fibers)?

Answer 25

_branch of n. IX_ 1. branches off at ggl. inf. n. IX 2. runs through canaliculus tympanicus to tympanic cavity 3. receives symp. fibers forming plexus tympanicus → GSS for **tympanic cavity + tuba**, also parasymp. preggl. fibers for **gl. parotis** _{3 = ggl. inf., 4 = n. tymp., 5 = plexus tymp.}

Question 26

Where is plexus tympanicus located? It is formed by which nerves? Main function.

Answer 26

in tympanic cavity _formed by:_ * parasymp. preggl. fibers of **n. tympanicus** (IX) * symp. postggl. fibers of **nn. caroticotympanici** (plexus caroticus int.) ⇒ gives off **n. petrosus min.** to ggl. oticum _{4 = n. tymp., 5 = plexus tymp., 6 = ggl. oticum}

Question 27

Describe the pathway of n. petrosus min. Pathway + function.

Answer 27

_branch of n. tympanicus, plexus tympanicus_ (IX) reenters cranium through **hiatus** **canalis n. petrosi min.**, leaves again through **foramen lacerum** to get to fossa infratemporalis → carries preggl. parasymp. fibers to ggl. oticum

Question 28

Which branches form the plexus pharyngeus? Function?

Answer 28

**_rr. pharyngei of n. IX and X_**_, innervates_ * pharyngeal constrictors * m. salpingo- and palatopharyngeus * m. levator veli palatini _{NOTE: SVM fibers mainly from n. vagus}

Question 29

What are the functions of rr. linguales of n. IX? Quality of fibers?

Answer 29

​_branches of n. IX_ * **GSS** → post. 1/3 of tongue * **SVS** → taste at post. 1/3 of tongue _{sajnos nem labeled, but shown though at root of tongue}

Question 30

What is the function of r. sinus carotici? Where can it be found? Quality of fibers? Another name.

Answer 30

**Hering's nerve**, branch of n. IX = **​GVS** runs to bifurcation of a. carotis → sensory innervation of **chemoreceptors of glomus caroticum, pressoreceptors in sinus caroticus** ₁₀

Question 31

Where can ggl. oticum be found? Roots + target organs?

Answer 31

medially to exit of n. V/3 in fossa infratemporalis * _symp. root:_ * *plexus car. int.** around a. cerebri media * _sensory root:_ * *rr. ganglionares** (V/3) ⇒ innervation of **gl. parotis** _{1 = ggl. oticum, 2 = n. V/3, 3 = n. petrosus min.}

Question 32

Where does ggl. oticum receive its preganglionic fibers from (nucleus + nerve)? Where to (nerve + target organ)?

Answer 32

GVM fibers from **ncl. salivatorius inf.** _preganglionic parasymp. fibers:_ * n. tympanicus (IX), **n. petrosus min.** (IX) _postganglionic parasymp. fibers:_ * **n. auriculotemporalis** (V/3) → gl. parotis = **JACOBSON ANASTOMOSIS** * **n. buccalis** (V/3) → gll. buccales

Question 33

List the nuclei of n. X. Quality of fibers.

Answer 33

_n. vagus_ _5 nuclei:_ * **ncl. ambiguus** (SVM) * **ncl. dorsalis n. vagi** (GVM) . * **ncl. spinalis n. trigemini** (GSS) * **ncll. tractus sol.** (SVS) * **ala cinerea lat.** (GVS)

Question 34

Describe the pathway of n. X in the head region.

Answer 34

_n. vagus_ exits brain in **sulcus paraolivaris lateralis**, leaves cranium through **foramen jugulare** forms * **ganglion sup.** n. X in foramen jug. * **ganglion inf.** n. X caudal to foramen jug. _{1 = ggl. sup., 2 = ggl. inf.}

Question 35

Where can ganglion inf. of n. X be found? Another name? Function.

Answer 35

= **ganglion nodosum** caudal to foramen jugulare _contains:_ * **pseudounipolar cell bodies of GVS** neurons from guts * **preganglionic cell bodies of SVS** neurons from vallecula epiglottica

Question 36

Where can ganglion sup. of n. X be found? Function?

Answer 36

_in foramen jugulare_ contains **pseudounipolar GSS** cell bodies of dura mater, auditory tube, larynx

Question 37

Which branches are given off by n. vagus in the head region? Pathway, quality of fibers + function.

Answer 37

_GSS_ * **r. meningeus** through foramen jug. back into cranium → meningi of fossa cranii post. * **r. auricularis** from ggl. sup. through canaliculus mastoideus, fissura tympanomastoidea → skin of meatus acusticus int. + cymba conchae

Question 38

Describe the pathway of n. X in the neck region. Which branches are given off?

Answer 38

runs together w/ a. carotis int. + v. jugularis caudally, then giving off 1. **r. lingualis** to epiglottis, larynx (_taste, SVS_) 2. **r. pharyngeus** 3. **n. laryngeus sup.** 4. **rr. cardiaci** 5. **n. laryngeus inf.** _{2 = ggl. inf., 3 = r. phar., 4 = n. lar. sup., 5 = rr. card. 6 = n. lar. inf.}

Question 39

Which structure is formed by r. pharyngeus of n. X? Function?

Answer 39

_branch of n. vagus_ forms together w/ n. IX and ggl. cerv. sup → **plexus pharyngeus** ⇒ **ALL mm. of pharynx, _exc._ m. stylopharngeus** + sensory innervation of **oro-, laryngopharnyx** 3

Question 40

Describe the pathway of n. laryngeus sup. Function.

Answer 40

_branch of n. vagus_ branches off at ggl. inf., btw a. carotis int. + wall of pharynx, branches cranially to larynx into * **r. externus** → m. cricothyroideus * **r. internus** → mucosa of pharynx sup. glottis _{2 = ggl. inf., 4 = n. laryng. sup.}

Question 41

What is the function of rr. cardiaci of n. X? Differentiate. Function + quality of fibers.

Answer 41

_branches of n. X_ * rr. cardiaci cervicales sup. * rr. cardiaci cervicales inf. * rr. cardiaci thoracici _2 functions:_ * **​preganglionic parasympathetic GVM** fibers → to plexus cardiacus, then postganglionic fibers of right vagus to SA-node, left to AV-node * **GVS** fibers to baroreceptors ₅

Question 42

Describe the pathway of n. laryngeus inf.. Function + quality of fibers?

Answer 42

_= **n. laryngeus recurrens**, branch of n. vagus_ * left: hooks around arcus aorticus * right: hooks around a. subclavia then btw trachea + esophagus to larynx cranially again → **all laryngeal mm.** (exc. m. cricothyroideus) + sensory innervation of **laryngeal mucosa inf. to glottis** ₆

Question 43

Which further branches are given off by n. X in the thorax and abdomen? Function?

Answer 43

* **rr. bronchiales** to plexus pulmonalis * **rr. oesophagei** to plexus oesophageus * **rr. gastrici ant. + post.** to stomach * **rr. hepatici** to liver + pylorus * **rr. coeliaci** to plexus coeliacus → GVM, GSS

Question 44

Differentiate btw the 2 truncus vagalis. Where are they located?

Answer 44

fibers of 2 vagal nn. mix, form 2 plexuses, ventrally and dorsally to oesophagus * **truncus vagalis ant.** = 90% fibers of left n. vagus * **truncus vagalis post.** = 90% of right n. vagus __REMEMBER:_ _{Dexter (right) belongs to Dorsal (post.)}

Question 45

Where does the innervation of n. vagus end?

Answer 45

**Cannon-Böhm point** in left colic flexure → around that area overlapping of parasymp. innervation of n. vagus and parasymp. innervation of plexus sacralis

Question 46

Differentiate btw the various functions of n. vagus w/r/t the different qualities of fibers.

Answer 46

* **SVM** → laryngeal, pharyngeal mm. * **GSS** → larynx, auricle + meatus ac. ext. * **SVS** (taste) → pharynx, epiglottis * **GVS** → guts, mechanorec. in lung, mechano-, chemorec. in heart, arcus aorticus * **GVM** → parasymp. innervation of guts (until Cannon-Böhm point)

Question 47

Where does n. XI originate from? Quality of fibers? Function?

Answer 47

**_n. accessorius_** (SVM) _2 roots:_ * **radix cranialis** from C1-6 * **radix spinalis** from ncl. n. accessorius (SVM) → n. sternocleidomastoideus, trapezius

Question 48

Describe the pathway of n. accessorius.

Answer 48

1. 6 roots of radix spinalis bundle and run through **foramen magnum** into skull 2. take up radix cranialis, give them off shortly after as **r. internus** to n. vagus 3. then exits cranium as **r. externus** through **foramen jugulare** to enter trigonum colli lat. _{1 = rad. spin., 2 = for. mag., 3 = rad. cran., 4 = for. jug., 6 = m. sternocl., 7 = m. trapezius}

Question 49

Where does n. XII originate from? Quality of fibers? Function?

Answer 49

**_n. hypoglossus_** originates from ncl. n. hypoglossi (SM) → **extrinsic and intrinsic muscles of tongue** (m. stylo-/hyo-/genioglossus), except _m. palatoglossus_ (innervated by plexus pharyngeus)

Question 50

Describe the pathway of n. XII.

Answer 50

1. exits brain in **sulcus paraolivaris medialis** 2. leaves cranium through **canalis n. hypoglossi** in foramen magnum 3. runs in trigonum caroticum, briefly accompanying fibers of ansa cervicalis prof. 4. to **sulcus lateralis linguae** _{1 = n. XII., 2 = canalis n. XII}