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Surgical Anatomy of Skull Base. Dr. Supreet Singh Nayyar, AFMC For more presentations, visit www.nayyarENT.com. Topography of Skull Base. Boundaries : Anterior : Incisors upper teeth Posterior: Superior nuchal line Lateral : Upper lateral teeth Zygomatic arch
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Surgical Anatomy of Skull Base Dr. Supreet Singh Nayyar, AFMC For more presentations, visit www.nayyarENT.com www.nayyarENT.com
Topography of Skull Base Boundaries : Anterior : Incisors upper teeth Posterior: Superior nuchal line Lateral : Upper lateral teeth Zygomatic arch Mastoid process www.nayyarENT.com
Topography of Skull Base Anterior Skull Base Central Skull Base Posterior Skull Base www.nayyarENT.com
Skull Base Anatomy Review • Key Openings • Foramen spinosum • Foramen ovale • Foramen lacerum • Foramen rotundum • Foramen magnum • Foramen of vesalius • Jugular foramen • Superior orbital fissure • Inferior orbital fissure • Optic canal • Vidian canal • Hypoglossal canal • Pterygopalatine fossa www.nayyarENT.com
Skull Base Anatomy Review • Foramen magnum • Medulla oblongata • Vertebral arteries • Anterior/Posterior spinal arteries • Hypoglossal canal • Hypoglossal nerve • Hypoglossal artery • Jugular Foramen • Pars nervosa: CN IX, inferior petrosal sinus • Pars vascularis: CN X, XI, jugular bulb www.nayyarENT.com
Foramen of Vesalius • Sphenoidal Emissary vein • Foramen Ovale • Mandibular nerve • Accessory meningeal artery • Lesser petrosal nerve • Emissary veins Skull Base Anatomy Review • Foramen Spinosum • Middle meningeal artery • Recurrent branch of mandibular nerve • Stylomastoid foramen • Facial nerve • Stylomastoid artery www.nayyarENT.com
Skull Base Anatomy Review • Foramen Lacerum • Ascending pharyngeal artery- meningeal branch • Nerve of pterygoid canal • Foramen rotundum • Maxillary nerve • Artery of foramen rotundum • Emissary veins • Pterygoid canal • Vidian nerve • Vidian artery www.nayyarENT.com
Skull Base Anatomy Review Cavernous Sinus Receives: Superior opthalmic vein Inferior opthalmic vein Sphenoparietal sinus Drains via: Petrosal sinuses Basilar plexus Pterygoid plexus Connection: Circular sinus Contains: CN III, IV, V1, V2, VI • Meckel’s Cave • Posterior aspect of cavernous sinus • Gasserian ganglion (sensory root ganglion of CN V) www.nayyarENT.com
Inferior Orbital Fissure • Infraorbital artery, vein, and nerve (V2 branch) • Optic Canal • Optic nerve • Ophthalmic artery Skull Base Anatomy Review • Superior Orbital Fissure • CN III, IV, V1, VI • Middle meningeal artery- orbital branch • Recurrent meningeal artery • Superior ophthalmic vein www.nayyarENT.com
Central Skull Base www.nayyarENT.com
Central Skull Base 6 1 1 2 5 3 4 4- Auditory Area5- Articular Area6- Infratemporal Foss 1- Pharyngeal Area2- Tubal Area3- Neurovascular Area www.nayyarENT.com
Pharyngeal Area Roof of Nasopharynx Boundaries of Nasopharynx : * Anterior * Lateral & Posterior * Inferior www.nayyarENT.com
Pharyngeal Area Pharyngobasilar fasia Fossa of Rosenmullar * Location- above & behind medial end ET * Depth- 2.5 cm * Apex- Carotid canal opening (post) & f. ovale, f. spinosum (lat) * Base- below Foramen lacerum www.nayyarENT.com
Tubal Area Eustachian Tube Scaphoid fossa Runs b/w petrous bone & greater wing sphenoid Opening- nasopharynx Paratubal muscles www.nayyarENT.com
Neurovascular Area Important structures are: Carotid sheath & its contents Styloid apparatus Facial Nerve www.nayyarENT.com
Carotid Sheath Compact network of aerolar tissue Carotid canal to arch of aorta Encloses : ICA above & CCA below IJV Vagus nerve Carotid Canal : ICA & Carotid plexus sympathetic nerve Parts of ICA www.nayyarENT.com
Jugular Foramen Divided into three compartments www.nayyarENT.com
Styloid Apparatus Bone- Styloid bone Ligaments- * Stylohyoid * Stylomandibular Muscles- * Stylohoid * Stylopharyngeus * Styloglossus www.nayyarENT.com
Facial Nerve Arise from Stylomastoid Foramen Branches: i) Post auricular nerve ii) Digastric branch iii) Temporofacial branch iv) Cervicofacial branch www.nayyarENT.com
Auditory Area Petrotympanic fissure of Glaser: * Chorda tympani * Ant br of tympanic artery www.nayyarENT.com
Infratemporal Fossa Location : below middle cranial fossa Boundaries Contents: * Med & Lat Pterygoid M * Maxillary A * Maxillary V * Pterygoid Venous Plexus * Br of Mandibular N www.nayyarENT.com
Pterygopalatine Fossa Small inverted pyramid shaped fossa Location Boundaries Communications www.nayyarENT.com
Anterior Cranial Base www.nayyarENT.com
Anterior Cranial Base from inside www.nayyarENT.com
Floor of Anterior Cranial Fossa • Depth of Olfactory fossa (Keros classification) * Type I – 1-3mm * Type II- 4-7mm * Type III- 8-17mm www.nayyarENT.com
Thank youFor more presentations, visit www.nayyarENT.com www.nayyarENT.com