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HEAD VIVASSample viva, 2010-2 (skull), 2010-1, 2009-1, 2008-2 (skull), 2006-2, 2005-2, 2004-2 (skull)(X-Ray – AP face)BonesNasal MaxillaZygomaticSphenoid MandibleLacrimalVomer EthmoidFrontalMandibleSinusesFrontalMaxillaryEthmoidMastoidWhat bony landmarks can you demonstrate on this film? What bones form the orbital margins?Margins = rim: Frontal -> maxilla -> zygomaticSuperior wall: Orbital part of frontal bone, w/ trochlea spineMedial wall: Orbital plate of ethmoid (paper thin), lacrimal w/ fossa and maxillaInferior wall: Maxilla continues around to meet zygomatic, thin and shared w/ maxillary sinusLateral wall: demarcated by the inferior orbital fissure, formed by frontal process of zygomaticApex: the lesser wing of the sphenoid with the optic cnal and superior orbital fissure laterallyWhat structures pass through the superior orbital fissure? 2008-2Opthalmic nerve (V1)Occulomotor nerve (III)Trochlear nerve (IV)Abducens nerve (VI)Opthalmic veinsSympathetic fibresWhere would you expect to find the infraorbital nerve? What structures does it innervate?From V2 – maxillary nerveVia inferior orbital fissure -> infraorbital groove/canal -> infraorbital foramenSupplies: Maxillary sinus, medial maxillary teeth, inferior eyelid, cheek, lateral nose, anterior tip of nasal septum, skin and oral muscosa of upper lip2010-2, 2009-1 (post circ), 2007-2 (MCA), X-ray: CT HeadIdentify the non–bony features on this CT scan.OrbitsTemporal lobes in middle cranial fossaPons 4th ventricle Cerebellum and vermisWhich bony sinuses are shown? Ethmoid, sphenoid, mastoidWhat is the blood supply of the cerebellum?Vertebral –> Basilar –> SAP (superior, anterior inferior, and posterior inferior) cerebellar arteriesIdentify the anatomical features on this CT scan through base of the skull 2009-2Bones: Occipital (w/ internal occipital protuberance), temporal (w/ petrous part/ridge), sphenoid (w/ dorsum sellae/posterior clinoid and anterior clinoid processes), nasalAir spaces: Mastoid air cells, sphenoid sinus, ethmoid sinus, nasal cavityIntracranial: 4th ventricle, cerebellum, vermis,?temporal lobes, ponsName the visible intracranial structures on this non-contrast CT scanLobes: (frontal,parietal/temporal,occipital)Lateral ventricles: (B)anterior and (F) posterior hornsChoroid plexus (F)Pineal gland (E)Thalamus (D)Straight sinus (G)Internal capsule (C)3rd ventricleBasal gangliaSylvian/lateral fissure (not shown)2007-2X-ray: CT BrainBasal ganglia:Caudate nucleusPutamenGlobus pallidusClaustrum2007-2Describe the circulation of CSF400-500ml/day formed in choroidal epithelial cells (plexus) in lateral, 3rd and 4th ventriclesLateral ventricles -> 3rd ventricle via intraventricular foramina3rd ventricle—> 4th ventricle via aqueductSome CSF passes into subarachnoid space via median and lateral aperturesMost CSF passes into interpeduncular and quadrigeminal cisternsCSF from the various subarachnoid cisterns flows superiorly through sulci and fissures on medial and superolateral surfaces of the cerebral hemispheresAbsorbed in arachnoid granulations esp. those that protrude into superior sagittal sinusWhat are the functions of CSFProtects brain by providing cushion effectBuoyancy effect to prevent compression of nerves and vessels2010-1, 2009-1 (CT – post circulation), 2008-2, 2006-2Draw or describe the circle of WillisA ferocious spider lives in the brain. His name is Willis!Note that he has a nose [pituitary gland], two suckers [mamillary bodies], eyes that look outward [internal carotid arteries], a crew cut [anterior communicating artery - blood flows in either direction], antennae [anterior cerebral arteries], a fuzzy beard [posterior communicating arteries - again, blood flows in either direction], 8 legs, a belly that, according to your point of view, is either thin (basilar artery) or fat (the pons), two feelers on his rear legs [posterior inferior cerebellar arteries], and male genitalia [anterior spinal artery]Willis has hairy armpits – the third cranial nerve exists between the posterior cerebral artery and the superior cerebellar artery [the first two sets of legs].The cerebellar arteries were named by a real SAP (S – superior, A – anterior inferior, and P – posterior inferior) [SA - the last two sets of legs] and supply the cerebellum and brainstem.Which part of the brain is supplied by each of the major arteriesACA - medial/sup surface of cerebrum except occipital lobe MCA - Lateral surfaces of both cerebral hemispheres excluding anterior part of frontal lobe and occipital lobe, including basal ganglia but not thalamusPCA - occipital lobe, inferior cerebrumWhat areas of the brain do the main arteries of the posterior circulation supply 2009-1Vertebral: cranial meninges & cerebellum (via AP)Basilar: brainstem, cerebellum (via S) & cerebrumPosterior cerebral: inferior aspect of cerebral hemispheres & occipital lobePosterior communicating: optic tract, cerebral peduncle, internal capsule and thalamusWhat motor and sensory areas lie in distribution of middle cerebral artery 2006-2Precentral gyrus (motor area) -> opposite half of body except legs and perineumPost central gyrus (sensory area) -> opposite half of body except legs and perineumAuditory and speech areas2011-2 (discuss), 2009-2, 2007-2, 2005-1Model: Orbit.?Extraocular muscles and eye movementsIdentify?the muscles responsible for eye movement and describe their function and nervesSRAdductsElevatesMedial rotationIIIMRIRDepressesLateral rotationIOAbductsElevatesLateral rotationLRVISODepressesMedial rotationIVMedial rotation = intorsion, lateral rotation = extorsionSO and IR act together to depressWhat are the effects of an oculomotor (CN III) nerve palsy? 2011-2, 2007-2Ptosis (levator palpebrae superioris paralysis, unopposed orbicularis oculis by VII)Dilated pupil fixed pupil (sphincter pupillae paralysis, unopposed dilator pupillae)Adducted and depressed -> “pupil down and out” (unopposed LR and SO)What is the effect of a trochlear (CN IV) nerve lesion? 2005-1Loss of superior oblique, over activity of inferior obliqueDiplopia when looking in (walk down stairs, reading)Extorsion - compensate by tilting to opposite shoulderAdditional: Abducent (CN VI) nerve palsyLateral rectus paralysisLoss of abductionUnopposed action of MR -> adduction2006-2, 2006-1Model: Eye Using the model, describe the structures of the eye.Vitreous bodyLensAnt & post chambers (aqueous humour)IrisPupilDescribe the structure of the walls of the eyeball Fibrous: cornea, conjunctiva, sclera Vascular (uveal tract): choroid, ciliary body, irisNervous: retina, optic disc, maculaDescribe the pupillary light reflex arc 2006-2Afferent: Light –> retina -> CN II (optic nerve) -> Pretectal nucleus –> both Edinger-Westphal nucleiEfferent: preganglionic parasympathetic CN III to ciliary ganglion -> short ciliary -> sphincter pupillaeDilator pupillae: is from cervical sympathetics, via internal carotid a, CNV1 (nasociliary) -> long ciliaryDescribe the formation and drainage of aqueous humour 2006-1 Production by ciliary processes (capillary diffusion)Enters posterior chamberPasses thru pupil to anterior chamberFilters thru iridocorneal angle to Canal of SchlemmDrains into anterior scleral veins2008-1Model: Tongue and musclesOn this model, identify structures that make up the floor of the mouthMandibleTongue (intrinsic m: sup long, trans, vert, inf long)LipsTeethGeniohyoid muscleHyoid boneStylohyoid muscleGenioglossus muscleDescribe the innervation of the tongueMotorAll except palatoglossus innervated by CN XII (Hypoglossal)Palatoglossus is actually a palatine m, therefore supplied by pharyngeal plexus (CN X, vagus)Sensation, Anterior 2/3Touch and temperature by lingual nerve?(branch of CN V3, mandibular)Taste for ant 2/3 (not vallate papillae) is via chorda tympani (branch of CN VII), the chorda tympani?joins the lingual and runs anteriorly in it’s sheathSensation, Posterior 1/3 of tongue and vallate papillae, both general sensory and taste are supplied by the lingual branch of glossopharyngeal (CN IX)Twigs of internal laryngeal (branch of vagus CN X) supply mostly general but some special sensation to a small area of tongue just anterior to epiglottis. These mostly sensory fibres also carry parasympathetic secretomotor fibres to serous glands of tongueParasympathetic fibres from chorda tympani travel with lingual to submandibular and sublingual salivary glands -> synapse in the submandibular ganglion which hangs from the lingual nerve2008-1, 2005-1Bone: MandibleDemonstrate the features of the mandibleCondylar process (head & neck)NotchCoronoid processRamusAngleBodyMental foramenMandibular foramen with lingulaMental tubercle and symphysisAlveolar processDescribe the features of the TM JointBones: Condyle of mandible, articular tubercle, mandibular fossaDisc: separates superior synovial cavity (gliding in/out) and inferior synovial cavity (hinge up/down)Stability from:Postglenoid tubercle and temperomandibular (lateral) ligament prevents posterior dislocationStylomandibular (styloid to angle) and Sphenomandibular (sphenoid to lingual) ligaments are medial and weakShape, joint capsule, teeth occlusion, musclesDescribe the mandibular attachments of the muscles of masticationTemporalis: temporal fossa -> medial coronoid & anterior ramusMasseter: maxillary process & zygomatic arch -> angle & lateral ramusLateral Pterygoid: greater wing sphenoid and ateral surface Lateral Pterygoid Plate -> joint capsule, disc & pterygoid fossa on neck of mandibleMedial Pterygoid: medial surface Lateral Pterygoid Plate & tuberosity of maxilla -> medial ramus below foramen2006-1Face - Sensory distribution to the earIdentify the sensory supply to the pinnaGreater auricular nerve (C2,3): Cranial surface and lower halfAuriculotemporal (V3): Upper half and most of the meatusWhat other nerves supply the ear and the canal.Lesser occipitalVagusGlossopharyngealFacial nerve allowing for the tympanic membrane2011-2Discuss: Trigeminal Nerve (CN V)What are the main branches of the trigeminal nerveNerveForaminaSuppliesV1: OpthalmicSensorySuperior orbital fissureSuprorbital, supratochlear, lacrimal, infratrochlear, external nasal, anterior and posterior ethmoidalV2: MaxillarySensoryForamen rotundumZygomatico-temporal, zygomatico-facial, infraorbital, pterygopalatine ganglionV3: MandibularSensoryForamen ovaleAuriculotemporal, buccal, inferior alveolar, mentalV3: MandibularMotorAnterior trunk -> muscles of mastication: temporalis, masseter, lateral and medial pterygoid (also tensor tympani and myohyoid)All three divisions supply meningeal branches also to supply dura of anterior (V1 and V2) and middle (V2 and V3) cranial fossa and tentrorium (V1). The posterior fossa is via C2 and C3 fibres.Bonus Q: Which nerve branch would you anaesthetize before repairing a lower lip lacerationMental nerve: as it emerges from mental foramen (terminal branch of inferior alveolar nerve, which in turn is a branch of mandibular division).2010-2 (discuss), 2006-2 (discuss), 2005-2, 2005-1, 2003-2Photo: Face (pg 49)Please identify the branches of the facial nerve on this photograph.TemporalZygomaticBuccalMandibularCervicalMnemonic: “Please Tell Ziggy Bob Marley Called”Please identify and name some facial muscles innervated by the facial nerve.Temporal: frontal belly of occipitofrontalis, auricularis, superior obicularis occuliZygomatic: inferior orbicularis oculi, zygomaticus major, zygomaticus minorBuccal: buccinator, nasalis, levator labii superiorisMandibular: orbicularis oris, depressor anguli oris, depressor labii inferioris, mentalisCervical: platysmaPlease describe the course of the facial nerve once it exits the skull base.Through stylomastoid foramen, near the origin of digastricGives of the posterior auricular branchDivides into superior and inferior divisionsBefore entering the posteromedial surface of the parotid glandWithin which it forms the parotid plexus (pes anserinus) divides into 5 branchesWhat other branches are there of this nerve? 2010-2, 2006-2Intermediate nerve: Carries the sensory and parasympathetic fibers of the facial nerveVia greater petrosal nerve -> pterygopalatine ganglion: parasympathetic fibres to lacrimal gland, sinuses and nasal cavityVia chorda tympani (w/ lingual nerve) -> special sensory taste fibers for anterior 2/3 of tongue, and parasympathetic secretomotor via submandibular ganglion to submandibular and sublingual glandsThe facial nerve also supplies the stapedius muscle prior to exiting the skull. ................
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