面神经的外科解剖

1、12021/4/27Embryology vN of 2nd branchial archv3rd wk fibro acoustic crest (DL aspect of hindbrain , cranial to otic placode)v4th wk Distinct FN 22021/4/27Contv5th wk GG formed FN divides(main trunk & CT)v7th wk 5 brs appear in parotid budv8th wk sulcus in post. Otic capsule(primitive FC)v16th wk neu

2、ral commmunications wit facial muscles is complete32021/4/27ContFacial nucleus neuroblasts in PONS with 6th N nucleus in close proximityAs brain develops pons expands “: any inflammatory event in this part both N involved42021/4/27Congenital AnomaliesMoebius syndrome(cong facial diplegia) Abnormal V

3、I ,VII,XII N nuclei FN absent / smaller Cong. Extra ocular muscle & facial palsyqTreacher collins syn(mandibulo facial dysostosis)qGoldenhars syn(oculoauriculo vertebral dysplasia)52021/4/27IntroductionVII Cr N ; Mixed N10,000 Motor , Sensory , parasympathetic fibersMotor root 7000 special visc. eff

4、. FibersSensory & Parasymp. 3000 carried by “”(N of wrisberg)NI consists of General visc. Eff. Special visc. Aff. Somatic Aff. 62021/4/2772021/4/27Facial Nerve Nuclei3 nuclei1)Motor nucleus lower pons below 4th ventricle2)Superior salivatory nucleus dorsal to motor N3)N of tractus solitarius medulla

5、 oblongata82021/4/27Central Connections of FNDorsal part of N B/L supra nuclear inn.Lower part of N C/L inn.Clinical varieties of VII N lesions92021/4/27ContFN course unusualFibers course towards floor of IV ventricleWrap around VI N nucl.Facial colliculusRetrace along ponsExits ponto medullary jn.1

6、02021/4/279、 人的价值，在招收诱惑的一瞬间被决定。22.2.2722.2.27Sunday, February 27, 202210、低头要有勇气，抬头要有低气。6:19:246:19:246:192/27/2022 6:19:24 AM11、人总是珍惜为得到。22.2.276:19:246:19Feb-2227-Feb-2212、人乱于心，不宽余请。6:19:246:19:246:19Sunday, February 27, 202213、生气是拿别人做错的事来惩罚自己。22.2.2722.2.276:19:246:19:24February 27, 202214、抱最大的希望，

7、作最大的努力。2022年2月27日星期日上午6时19分24秒6:19:2422.2.2715、一个人炫耀什么，说明他内心缺少什么。2022年2月上午6时19分22.2.276:19February 27, 202216、业余生活要有意义，不要越轨。2022年2月27日星期日6时19分24秒6:19:2427 February 202217、一个人即使已登上顶峰，也仍要自强不息。上午6时19分24秒上午6时19分6:19:2422.2.27Course 122021/4/27Intra cranial portionqFrom brainstem to fundus of IAMq length

8、 24mmqFN crosses CP angle wit 8th CN & NIqDevoid of epineuriumqThin layer of pia mater1)Iatrogenic trauma in CP angle tumour surgery2)Diff to identify in schwannoma(no conn tissue)132021/4/27Meatal SegmentEnters in ant sup segment of IACLength 5 12 mmCrista falciformisBills barNo separate sheathShar

9、es wit NI & 8th CNFN merges wit NI at fundus142021/4/27Intra Temporal RegionFrom fundus to SMFLength 28 to 30 mmLongest bony canal3 segments by 2 genus 152021/4/27Labyrinthine SegmentvNarrowest(0.68) & Shortest(3-5mm)vNo anastomosing arteriesvPeriostium is thickervPost. Sup. to cochleavAnt. Med. to

10、SSCCvPost. to vestibulevDistal end 162021/4/271)Anatomical bottle neck ischemia in oedema2)Part most vulnerable for ischemia(no art anast)3)Temporal bone # - MC injured:Bipolar gang cellsAff. input somatic & special visceral affSecretomotor F to lacrimal gld(witout synapse)172021/4/27Tympanic Segmen

11、tHorizontal segmentFrom GG to 2nd genuLength 8 to 11mmLies beneath LSCC & above OW above & medial to 182021/4/27ContNerve lies lateral & posterior to Creats 2 recesses1.Facial recess (lat)2.Sinus tympani(med)q2nd genu192021/4/27ContProcessus cochleariformis(consistant landmark)Imp landmark for 2nd g

12、enu -LSCC -Pyramidal eminence -B/w short process of incus(L) & LSCC(M) FR & ST MC sites for recurrence202021/4/27Mastoid SegmentVertical segmentFrom 2nd genu(PM) to SMF(AL)Longest (13mm)Landmark “FN leaves FC via SMF(b/w mastoid tip & styloid process)212021/4/27Extra Temporal Region From SMF to term

13、inal branchesRuns in substance of parotidMain trunk divides - upper temperofacial - lower cervicofacialqSuperficial to Retromandibular V 222021/4/27ContRMVFNDMSCMEJV232021/4/27Branches Intra temporal region :1)GSPN2)N to stapedius3)Chorda tympani4)Sensory auricular branch242021/4/27GSPNFrom GG2 type

14、s of fibersPregang para symp Pterygopalatine gang.Post gang lacrimal G qSensory fibers to nasal & palatine gldsJoins deep petrosal N N to pterygoid canal252021/4/276mm above SMFSupply stapediusJoins auricular br of vagusSupply retro auricular groove & concha262021/4/27Chorda tympaniv4mm above SMFvLa

15、t & ant to FNvPost canaliculusvLat to LP of incus & med to malleusvAnt canaliculus(Canal of huguier)v2 types of fibersvPre G parasym sub mand Gang vPost G submand & subligual GvSpecial sensory ant 2/3rd of tongue272021/4/271)GSPN - landmark in middle cranial fossa approach2)CT landmark in post tympa

16、notomy3)CT lat margin of facial recess4)CT medial limit for facial ridge reduction282021/4/271)Post.auricular N(occ frontalis &muscles of pinna)2)Muscular Brs(post belly of digastric &stylohyoid)292021/4/27Terminal branches302021/4/27BUCCALMANDIBULARCERVICALZYGOMATICTEMPORALCross zygomatic archAuric

17、ularis ant & sup;frontalis;orb oculi & corrugator superciliiCross zygomatic boneOrbiculatis oculi312021/4/271-2cm below inf ramus of mandibleMuscles of lower lip&chinPlatysma &depressor anguli oris1 cm below zyg archAlong parotid ductBUCCALMANDIBULARCERVICAL322021/4/271)Risorius (smirk) 2)Buccinator

18、 (aids chewing) 3)Levator Labii Superioris 4)Levator Labii Alaque Nasi (snarl) 5)Levator Anguli Oris(soft smile) 6)Nasalis (Flare Nostrils)7)Orbicularis Oris (Purse Lips)332021/4/27Anatomical RelationshipCT may exit thru SMF2nd genu is more acute & lateralN trunk on exit from SMF is more ant & latN

19、very superficial over angle of mandibleCT exits prox to SMF2nd genu less acute & more medialN trunk is less anterior & deeperN superficial over angle of mandibleChild Adult 342021/4/27Blood Supply352021/4/27Surgical LandmarksEar surgery:1)GG lies superior to 2)2nd genu hugs inf aspect of 3)FN lies a

20、bove lies lat to FN5)FN runs behind 6)FN lies 6-8mm inf to mastoid seg362021/4/27ContParotid surgery 1cm deep&inf3)N lies lat to 4)Superficial to 5)N bisects angle b/w & ear canal372021/4/27Variations MC variations1.FN displacements2.Dehiscence of fallopian canalDehiscence in tympanic seg (35-55%)-m

21、cVertical seg variations1.Bipartite N2.Ant displaced N3.Wit post hump382021/4/27Cont N to stapedius & CT N variationLarge CT can be real FN(shouldnt sacrifice)1.FN partially obliterating stapes footplate2.Bifurcation of FN3.FN rests on foot plate 4.FN rests on promontory392021/4/27402021/4/27412021/4/27Cont1.Malleus-incus fixation2.IS disconnection