--- module: 080-03 language: en chapter: 80 title: "Head, Neck, Cranial Nerves, Pharynx, and Larynx Anatomy" module_title: "Cranial nerves, arterial and venous pathways, autonomic ganglia, and lymphatics" source_sha256: 431883c9426c0bff5c636be1eacba8362b63bbec10067e88c775e51719612a65 --- # Cranial nerves, vessels, ganglia, and lymphatics ## Olfactory and optic pathways ### Olfactory filaments cross cribriform plate #### Shearing: anosmia and CSF leak ### No obligatory thalamic relay #### Smell linked to memory and emotion ### Optic nerve is a CNS tract within meninges #### Raised pressure along sheath: papilloedema ### Chiasm: nasal fibres cross ### Chiasm above pituitary, near carotid vessels ## Ocular motor nerves and cavernous sinus ### Oculomotor between posterior cerebral, superior cerebellar ### Oculomotor: levator, three recti, inferior oblique ### Trochlear: long course, vulnerable in trauma ### Abducens through Dorello canal #### Within cavernous sinus beside carotid ### Lateral wall: oculomotor, trochlear, V1, V2 ### Ophthalmic and facial veins transmit infection ### Parasympathetic: ciliary ganglion to sphincter ### Sympathetic: superior cervical ganglion to dilator ## Trigeminal divisions ### Ganglion in Meckel cave ### Ophthalmic: lacrimal, frontal, nasociliary #### Forehead, cornea, upper lid, nasal dorsum ### Maxillary via rotundum to pterygopalatine fossa #### Midface, upper teeth, palate, maxillary sinus ### Mandibular exits ovale with motor root #### Motor: mastication, mylohyoid, tensors ### Lingual nerve receives chorda tympani ### Injury level determines deficit pattern ## Facial nerve ### Meatus, facial canal, geniculate, stylomastoid ### Branches within the canal #### Greater petrosal to pterygopalatine ganglion #### Nerve to stapedius #### Chorda tympani: taste and salivary fibres ### Parotid plexus and five terminal branches #### Does not supply parotid secretion ### Intracranial lesion: taste, tears, stapedius ### Upper motor-neuron lesion spares forehead #### Bilateral cortical input ## Lower cranial nerves ### Glossopharyngeal: stylopharyngeus, posterior tongue #### Carotid sinus and body afferents #### Parotid via lesser petrosal and otic ganglion ### Vagus descends in carotid sheath #### Superior laryngeal: internal sensory, external motor ### Accessory superficial in posterior triangle #### Weak shoulder elevation, head rotation ### Hypoglossal hooks over hyoglossus #### Vulnerable in submandibular, carotid surgery ## Autonomic ganglia ### Four parasympathetic ganglia with trigeminal branches #### Ciliary: oculomotor to eye #### Pterygopalatine: greater petrosal to glands #### Submandibular: chorda tympani to two glands #### Otic: glossopharyngeal to parotid ### Postganglionic fibres hitchhike on trigeminal ### Sympathetic fibres pass through without synapse #### Shared routes give combined deficits ### Horner syndrome #### Ptosis, miosis, apparent enophthalmos #### Anhidrosis localises pre or postganglionic ## Arterial supply ### Internal carotid: petrous, cavernous, orbit, brain ### External carotid: face, scalp, dura, neck ### Maxillary artery through two fossae #### Middle meningeal via foramen spinosum #### Sphenopalatine: key in epistaxis ### Vertebral enters C6 foramen, curves round atlas ### Carotid anastomoses: collateral or embolic route ## Venous drainage ### Dural sinuses are valveless channels ### Superior sagittal to transverse, sigmoid, jugular ### Straight sinus receives great cerebral vein ### Cavernous sinuses communicate across midline ### Pterygoid plexus links face and cavernous sinus ### Emissary veins valveless through foramina #### Equalise pressure, carry infection and tumour ## Lymphatics ### Superficial ring drains to deep cervical chain ### Deep nodes follow internal jugular ### Clinical levels guide cancer surgery ### Waldeyer ring around pharyngeal entry #### Palatine tonsil near glossopharyngeal nerve ##### Referred ear pain, bleeding risk ### Virchow node enlarges via thoracic duct ### Right lymphatic duct drains right upper body ## Localisation as routing ### Trace deficit from brainstem exit to lymph ### Connected pathways, not isolated names