Cranial nerves

Nervi craniales

Cranial nerves

• 12 pairs• Emerging from the brain stem (except CN I

and CN II), where they have their nuclei (somatomotor, somatosensitive, sensoric, parasympathic)

• Outside brain - ganglias (sensitive, parasympathetic)

• Sympathetic fibres join along the course, from plexuses following the blood vessels

Cranial nervesCranial nerves• CN I – n. olfactorius - sensoric• CN II – n. opticus - sensoric• CN III – n. oculomotorius - motor + PS• CN IV – n. trochlearis - motor• CN V – n. trigeminus – sensitive + motor• CN VI – n. abducens - motor• CN VII – n. facialis – motor + PS • CN VIII – n. vestibulocochlearis - sensoric• CN IX – n. glossopharyngeus – PS + sens + motor + senz• CN X – n. vagus – PS + motor + sensitive + sensoric• CN XI – n. accessorius - motor• CN XII – n. hypoglossus – motor

Cranial nerves origin in the brain stem

General scheme for CN studying

1. number, Latin and English term2. developmental type of CN3. nuclei + their location4. transmitted modalities5. where CN submerge into skull6. course of CN + topography7. branches8. overview of supplied area9. clinical examination, reflexes10. palsy / iritation

I – n. olfactoriusI – n. olfactorius

• Olfactory nerve • Rather bundle of nerve fibres, than a nerve• Pure sensoric nerve

• Bipolar neurons • Ability to regenerate• N. terminalis, n. vomeronasalis - rudiments

Olfactory tractOlfactory tract

• Fila olfactoria, bulbus – interconnection, tractus, trigonum, stria olfactoria (med. + lat.), brain areas

• Disorders: anosmia, parosmia, kakosmia

II – n. opticusII – n. opticus

• Optic nerve• Diencephalon pouch• Consist of axons of the 3rd nerves of the optic tract• Covers: vagina externa + interna (from meninges)• A.+ V. centralis retinae

• Pars intraocularis• Pars orbitalis• Pars canalis optici• Pars intracranialis

Optic tractOptic tract

• N. opticus –> chiasma opticum –> tractus opticus

• Disorders: amaurosis, hemianopsia, scotom

Nerves for the Nerves for the eye movementeye movement

External muscles of the eye-ballExternal muscles of the eye-ball• 4 recti (superior, inferior, lateralis, medialis)• 2 oliqui (superior + inferior) • m. levator palpebrae superioris • smooth muscles: m. orbitalis, mm. tarsales

Nerves for the eye movementNerves for the eye movement• CN III, IV and VI for 7 muscles• CN IV and VI pure somatomotor functions • CN III – somatomotor + PS functions

III - n. oculomotoriusIII - n. oculomotorius• Oculomotor nerve• nc. oculomotorius (somatomotor)• nc. Edinger-Westphal (PS)• Ramus superior + inferior (r. communicans ad ggl. ciliare)• Palsy: diplopia, divergent strabismus, ptosis, mydriasis• Innervates:

– m. rectus superior – m. rectus medialis – m. rectus inferior – m. obliquus inferior – m. levator palpebrae sup.

ggl. ciliareggl. ciliare

• Ciliary ganglion

m. sphincter pupilae m. dilatator pupilae

m. ciliaris

IV - n. trochlearisIV - n. trochlearis

• Trochlear nerve, pure somatomotor • Innervates m. obliquus superior• Nucleus trochlearis• Only one which emerges from the brain stem dorsally • sinus cavernosus, fissura orbitalis superior, ATC Zinni• Palsy: diplopia when looking down and laterally (downstairs)

IV - n. abducensIV - n. abducens

• Abducens nerve, pure motor (nc. abducens)• Innervates m. rectus lateralis• Dorello´s canal, sinus cavernosus, fissura orbitalis superior, ATC Zinni• Palsy: diplopia, convergent strabism

Nerves for eye-movementNerves for eye-movement

OrbitaOrbita

Sinus cavernosusSinus cavernosus

Anulus tendineus communis ZinniAnulus tendineus communis Zinni

Anulus tendineus communis (Anulus tendineus communis (Zinni)

V – n. trigeminusV – n. trigeminus

• Trigeminal nerve – 3 branches• 3 sensitive nuclei:

– nc. mesencephalicus– nc. pontinus– nc. spinalis (in medulla oblongata)

• 1 motor nucleus: nc. motorius• Vegetative part joins along the course• Emerging from the pons• Sensitive ganglion trigeminale (Gasseri) • PS ganglions (ciliare, pterygopalatinum, oticum,

submandibulare)

VV11 – n. opthalmicus – n. opthalmicus

• Senzitive nerv• 3 main branches: – n. frontalis– n. lacrimalis (sensitive + PS)– n. nasociliaris

• Connections with nerves for eye-movement (sensitive fibres)

• Parasympatic fibres for n. lacrimalis from connection from n. zygomaticus (V2)

VV11 – n. opthalmicus – n. opthalmicus

VV22 – n. maxillaris – n. maxillaris• Sensitive nerve• Parasympathetic fibres for ggl. pterygopalatinum from n. facialis• passes foramen rotundum, branches out in fossa

pterygopalatina – n. infraorbitalis– n. zygomaticus – nn. pterygopalatini

VV33 – n. mandibularis – n. mandibularis

• Sensitive and motor nerve• Parasympatic fibres for ggl. oticum from n. IX,

for ggl. submandibulare from VII• passes foramen ovale, branches out in fossa infratemporalis

VV33 – n. mandibularis – n. mandibularis

– muscle branches (n. massetericus, nn. temporales profundi, nn. pterygoidei)

– n. bucalis – n. auriculotemporalis – n. lingualis – n. alveolaris inferior

VV33 – n. mandibularis – n. mandibularis

Ganglia of trigeminusGanglia of trigeminus

• PS fibres for glands interconnects in the ganglias• Sympatic fibres for smooth muscles pass through• Sensitive fibres pass through

ggl ciliare

ggl submandibulare ggl oticum

ggl pterygopalatinum

ggl. ciliareggl. ciliare

• Ciliary ganglion

m. sphincter pupilae m. dilatator pupilae

m. ciliaris

ggl. pterygopalatinumggl. pterygopalatinum

• PS for lacrimal gland, glands of nose, mouth from n. petrosus major (n. VII)

ggl. oticumggl. oticum

• PS from nucleus of CN. IX to parotid gland

ggl. submandibulareggl. submandibulare

• Near of n. lingualis and submandibular gland

• PS from n. lingualis (by chorda tympani, n. VII) • S from plexus of a. facialis • rr. glandulares for submandibular and sublingual glands (PS)