上海交通大学耳鼻咽喉科学英文版课件 facial nerve palsy.ppt

* Facial Nerve Palsy Anatomy Facial nerve is a mixed nerve, having a motor root and a sensory root Motor root supplies all the mimetic muscles of the face which develop from the 2nd brachial arch Sensory root “nerve of Wrisberg” carries taste fibers from the anterior 2/3 of the tongue and general sensation from the concha and retroauricular skin Also it carries secretomotor fibers to the lacrimal, submandibular and sublingual glands as well as those in the nose and palate Anatomy Anatomy: Parts Intracranial part Intratemporal part Extracranial part Course of the Facial Nerve Intracranial Arises at the pontomedullary junction and courses with CNVIII to the internal acoustic meatus 12mm Intratemporal Meatal Labyrinthe segment Tympanic segment Mastoid segment Course of the Facial Nerve Extracranial From stylomastoid foramen to pesanserinus Course of the Facial Nerve Anatomy: Branches Greater superficial petrosal nerve Nerve to stapedius Chorda tympani Comunicating branch Posterior auricular nerve Muscular branches Peripheral branches: “Pes anserinus” Presentation Functional and cosmetic problems Upper lid fails to drop down and close Lower lid loses tone and sags downward May evert leading to ectropion Produces lagophthalmos and consequent corneal exposure. Presentation Interruption of the tear film Leads to drying of cornea Ocular discomfort Corneal ulcers Infection Perforation Upper motor neurone (UMN) can wrinkle their forehead (unless bilateral lesion) Lower motor neurone (LMN) cant wrinkle their forehead Presentation House-Brackmann Facial NerveGrading Scale I. Normal II. Mild dysfunction (slight weakness noticeable on close inspection) III. Moderate dysfunction (obvious weakness, but not distinguishing differences between the two sides of the face) IV. Moderately severe dysfunction (obvious weakness and disfigurement) V. Only barely perceptive motor function VI. Complete paralysis Diagnosis History Presentation Hearing test Vestibular function MRI