Cranial nn. I - VI details Flashcards
List the 4 autonomic ganglia that can be found in the head and neck region.
Function?
paired, parasymp. (GVM) ganglia
- ggl. ciliare: sphincter pupillae, ciliary m.
- ggl. pterygopalatinum: gl. lacrimalis, gll. of nasal cavity
- ggl. oticum: gl. parotis
- ggl. submandibulare: gll. submand., subling.
What are the 3 roots entering each of the parasympathetic ganglia?
Quality of fibers?
motor root
- presynaptic parasympathetic nerve fibers (GVM)
- terminate in the ganglion and synapse with the postsynaptic fibers that project to target organs
sympathetic root
- postsynaptic sympathetic fibers (GVM)
- traverse the ganglion without synapsing
sensory root
- general somatosensory fibers (GSS)
- also do not synapse in the ganglion
NOTE: some ganglia also carry special sensory fibers (SVS) for taste sensation
Where does the first cranial nerve originate from?
Quality of fibers?
Pathway.
General function.
n. olfactorius (SVS)
- 20 fila olfactoria originating from olfactory mucosa
- run through lamina cribrosa
- terminate in bulbus olfactorius
- via tractus olfactorius to primary olf. cortex
→ olfaction
<span><u>NOTE:</u> bulbus olfactorius = </span>equivalent to cranial nerve ncl.<br></br>1 = filia olf., 2 = olf. muc., 3 = lamina crib., 4 = bulbus olf.
What is special about the fila olfactoria?
bipolar neurons → form axons (unmyelinated) that terminate in bulbus olfactorius
<u>NOTE:</u> bulbus olfactorius = equivalent of cranial nerve ncl.
Where does the second cranial nerve originate from?
Quality of fibers?
Pathway.
General function.
n. opticus (SSS)
- processes of retinal ganglion cells pass together through papilla of retina
- pierce sclera, exit orbit together w/ a. ophthalmica through canalis opticus
- enter fossa cranii media, reach chiasma opticum
- run via tractus opticus to
- corpus geniculatum lat. of thalamus (→ visual cortex)
→ vision
What are 2 other names for the papilla of the retina?
- blind spot
- discus n. opticus
What is a unique feature of n. opticus?
no real peripheral nerve, rather extension of CNS bc
- myelinated by oligodendrocytes
- dura/pia mater
once it leaves the sclera
Describe how the different fibers of n. opticus behave in chiasma opticum.
-
fibers from medial part of retina = lat. visual field
→ cross to contralateral side -
fibers from laterla part of retina = med. visual field
→ traverse chiasma opticum w/o crossing
⇒ in tractus opticus crossed + uncrossed fibers
Which nerves are responsible for the movement of the eye?
- n. oculomotorius
- n. trochlearis
- n. abducens
Describe the pathway of the third cranial nerve.
Branches?
General function.
n. oculomotorius
- exits mesecenphalon in fossa interpeduncularis
- runs through sella turcica, pierces dura mater
- through lat. wall of sinus cavernosus
- traverses fissura orbitalis sup. to reach orbit
- passes through anulus tendineus communis to bifurcate into r. sup., r. inf.
→ movement of eye
2 = fissura orb. sup., 3 = r. sup., 4 = r. inf.
What is anulus tendineus?
Other names.
anulus of Zinn, annular tendon
ring of fibrous tissue surrounding n. opticus at its entrance at the apex of the orbit
origin for 5 of 7 extraocular muscles
(no m. obliquus inf., levator palpebrae sup.)
What are the contents of anulus tendineus?
- n. III, IV, VI
- n. nasociliaris (V/1)
- a. ophthalmica
- a. centralis retinae
Where does n. oculomotorius originate from?
Quality of fibers?
originates in mesencephalon from
- ncl. n. oculomotorii = SM
- ncl. n. accessorius n. oculomotorii = parasymp., GVM
Which muscles are innervated by n. III?
Differentiate btw striated and smooth m.
-
ncl. n. oculomotorii:
5 out of 7 striated extraocular mm.
→ m. obliquus inf.
→ m. rectus sup., med., inf.
→ m. levator palpebrae sup.: lifting eyelid -
ncl. n. accessorius n. oculomotorii:
smooth intraocular mm.
→ m. ciliaris: accommodation
→ m. sphincter pupillae: constriction of pupil
function of ncl. n. III (+ m. levator palpebrae)
Which branches are given off by n. oculomotorius?
Which mm. are innervated by them?
-
r. sup. (the 2 sup.)
→ m. rectus sup.
→ m. levator palpebrae sup. -
r. inf. (rest)
→ m. rectus med., inf.
→ m. obliquus inf.
→ branch to ganglion ciliare: m. sphincter pupillae, m. ciliaris
3 = r. sup., 4 = r. inf., 5 = ggl. ciliare
Where can ggl. ciliare be found?
Sympathetic, sensory root.
Target organs?
dorsal to eyeball, lateral to n. opticus
-
symp. = plexus ophthalmicus
→ smooth m. dilatator pupillae -
sensory root = n. nasociliaris (n. V/1)
→ cornea
Where does ggl. ciliare receive its preganglionic fibers from (nucleus + nerve)?
Postganglionic fibers via which nerve to which organ?
ncl. accessorius n. III (EDINGER- WESTPHAL)
preganglionic parasymp. fibers:
- r. inf. n. III
postganglionic parasymp. fibers:
- nn. ciliares breves (n III)
⇒ m. sphincter pupillae, m. ciliaris
Where does the fourth cranial nerve originate from?
Quality of fibers?
Pathway.
General function.
n. trochlearis (SM)
- exits brain dorsally caudally to coll. inf.
BUT: fibers CROSS to contralat. side - runs in cisterna ambiens to lateral wall of sinus cavernosus
- through fissura orbitalis sup.
→ eye movement
2 = dorsum sellae, 3 = sinus cav., 4 = fissura orb. sup
Which m. is innervated by n. trochlearis?
Function?
m. obliquus sup.
→ cf. picture (in fixed position, if eyeball adducted depressor of eyeball)
What is the function of ncl. spinalis n. trigeminus?
Quality of fibers?
GSS
protopathic sensation of face
→ sensibility of deep tissue to crude touch/pressure, pain/heat
NOTE: somatotopic organization
1
What is the name of the first division of n. trigeminus?
Describe its pathway + branches.
n. ophthalmicus (V/1)
- enters lat. wall of sinus cavernosus after exiting ggl. trigeminale
- r. meningeus recurrens to meningi
- enters fissura orbitalis sup., giving off 3 further branches:
- n. lacrimalis
- n. frontalis
- n. nasociliaris
9 = ggl. trig., 1 = r. men. rec., 2 = n. nasocili., 3 = n. front., 4 = n. lacr.
What is the function of n. V/1?
n. ophthalmicus
sensory innervation of orbita, eye, cornea, skin of forehead, nose, upper nasal cavity, nasal septum
1
What is the function of r. meningeus recurrens?
Another name.
branch of n. V/1, also: r. tentorius
- meningi of fossa cranii media
- tentorium cerebelli
1
Describe the pathway of n. lacrimalis.
Function?
branch of n. V/1
runs laterally in orbit to carry postganglionic r. communicans of n. zygomaticus (V/2) from ggl. pterygopalatinum to lacrimal gland, then to skin
→ lat. part of orbit, upper eyelid, conjunctiva
4 = n. lacr., 5 = n. zygom., 6 = r. communicans
Describe the pathway + branches of n. frontalis.
Function?
branch of n. V/1
runs ventrally in orbit btw n. lacrimalis/n. nasociliaris, branches into
-
n. supraorbitalis branches into
r. med. through incisura frontalis → forehead
r. lat. through foramen supraorb. → vertex -
n. supratrochlearis
→ nasal root + upper eyelid
3 = n. front., 7 = n. supraorb., 8 = n. supratroch.
Describe the pathway + branches of n. nasociliaris.
Function?
branch of n. V/1
runs medially through anulus tendineus in orbit, gives off 5 branches:
-
n. ethmoidalis ant. + post.: through foramina ethmoidalia/lamina cribrosa
→ ethmoidal air cells, sinus sphenoidalis, nasal septum -
n. infratrochlearis:
→ med. part of orbit, root of nase, conjunctiva -
nn. ciliares longi:
→ cornea - r. communicans cum ganglio ciliari
2 = n. nasoc., 3, 4 = n. ethm. post., ant., 5 = n. infratro., 6 = r. comm., 8 = nn. cili. long.
What is the name of the second division of n. trigeminus?
Describe its pathway + branches.
n. maxillaris (V/2)
- enters basolat. wall of sinus cavernosus after exiting ggl. trigeminale
- r. meningeus to fossa cranii ant., med.
- exits cranium through foramen rotundum to give off branches in fossa pteryogpalatina:
- rr. ganglionares
- n. zygomaticus
- rr. alveolares sup. post.
- n. infraorbitalis
1 = ggl. trig., 2 = for. rot.3 = rr. ggll., , 4 = ggl. pterygop., 5 = n. zygo., 7 = n. infraorb., 10 = r. men.
What is the general function of n. V/2?
n. maxillaris
sensory innervation of
- skin btw eye and lips
- area lat. to eye,
- post. 2/3 of nasal cavity
- palate
- teeth of upper jaw
2
What is the function of rr. ganglionares of n. V/2?
List the rr. ganglionares + describe their pathway.
sensory fibers crossing ganglion pterygopalatinum, also carry postganglionic parasymp. fibers to n. zygomaticus
-
rr. nasales post. sup. lat., med.
through for. sphenopalatinum → post. 2/3 of nasal cavity + tuba auditiva + n. nasopalatinus (cf. own card) -
n. palatinus maj., min.
through canalis palatinus → palate + tonsil
also give off rr. nasales post. inf. - r. pharyngeus → nasopharynx
3 = rr. ganglionares, 4 = ggl. pterygopalatinum
Describe the pathway of n. nasopalatinus.
Another name?
Function?
branch of V/2, also: n. nasopalatinus of SCARPA
longest branch of n. nasales post. sup.
runs through foramen sphenopalatinum to sulcus nasopalatinus, then through canalis incisivus to
→ hard palate + mucosa
sajnos nem labelled
Describe the pathway + branches of n. zygomaticus.
Function?
branch of n. V/2
carries parasymp. postganglionic fibers from ggl. pteryogpalatinum, enters orbit via fissura orbitalis inf. to
- give off fibers via r. communicans to n. lacrimalis (V/1) → lacrimal gland
- give off r. zygomaticotemporalis, -facialis, through canalis zygomaticus → temple + forehead
4 = ggl. pterygop., 5 = n. zygom., 6 = r. comm.
Describe the pathway + branches of n. infraorbitalis.
Function?
branch of n. V/2
enters orbit via fissura orbitalis inf. gives off
- rr. alveolares sup. med., ant. → teeth of upper jaw
then runs through foramen infraorbitale to give off
- rr. palpebrae inf. → lower eyelid
- rr. labiales sup. → upper lip
8 = n. infraorb., 9 = for. infraorb.
As a summary…
Which nn. innervate the upper jaw?
- rr. alveolares sup. post. = direct branches of n. V/2 → molars
- rr. alveolars sup. med. + ant. = branches of n. infraorbitalis (n. V/2) → remaining teeth
⇒ form plexus dentalis sup.
rr. alveolares sup. post not labeled, but visible, 7 = n. infraorb.
What is the name of the third division of n. trigeminus?
Describe its pathway + branches.
n. mandibularis (V/3)
- exits cranium through foramen ovale
- enters fossa infratemporalis
-
gives off 5 sensory and 4 motor branches
- r. meningeus
- n. auricotemporalis
- n. alveolaris inf.
- n. buccalis
- n. lingualis
- 4 motor branches
1 = r. men., 3 = n. bucc., 4 = n. alv. inf., 9 = n. auricot., n. lingualis shown but not labeled
What is the function of n. V/3?
n. maxillaris
sensory innervation of
- chin, lower jaw, incl. teeth, up to temple, buccal mucosa
- mm. of mastication
- ant. 2/3 of tongue
3
Describe the pathway of r. meningeus of n. V/3.
Function?
first branch, enters together w/ a. meningea media foramen spinosum fossa cranii media to innervate meningi
1 = r. meningeus, 2 = a. meningea med.
Describe the pathway + branches of n. auricotemporalis.
Function?
branch of n. V/3
around a. meningea med., receives postganglionic parasymp. fibers (n. IX) via rr. ganglionares (V/3) from ggl. oticum to carry them to gl. parotis, terminates w/ sensory branches
- n. meatus acusticus int. to eardrum
- sensory innervation of temple, ant. part of auricle
2 = a. men. med., 9 = n. auriculotemp.
Describe the pathway of n. alveolaris inf.
Function?
branch of n. V/3
runs btw mm. pterygoidei from fossa infratemporalis through foramen mandibulae to lower jaw, eventually exits as n. mentalis through foramen mentale
→ sensory innervation of lower jaw + teeth, gingiva, chin
4 = n. alveol. inf., 5 = rr. to roots of teeth, 6 = to gingiva, 7 = n. ment., 8 = for. ment.
Describe the pathway of n. buccalis.
Function?
branch of n. V/3
runs btw heads of m. pterygoideus lat. to pierce m. buccinator, then
→ sensory innervation of buccal mucosa + adjacent gingiva
3 = n. bucc., 10 = m. buccinator
Where does the sixth cranial nerve originate from?
Quality of fibers?
Pathway.
General function.
n. abducens (SM)
- originates from. ncl. n. abducentis
- runs in rostral direction on clivus to enter dura (longest intradural pathway)
- through sinus cavernosus to
- fissura orbitalis sup. and anulus tendineus into orbit
→ eye movement
1 = n. VI, 2 = enters dura on cliv., 3 = sinus cav., 4 = fissura orb. sup.
Which m. is innervated by n. VI?
Function?
m. rectus lat.
obviously abducts eye
