Presentation on theme: "Anatomy of Nose & Paranasal Sinuses Dr. Vishal Sharma."— Presentation transcript:
Anatomy of Nose & Paranasal Sinuses Dr. Vishal Sharma
Development of nose
Face develops from 5 projections: frontonasal process (ectoderm over forebrain) + 2 maxillary processes + 2 mandibular processes (1 st arch) An ectodermal olfactory placode divides fronto- nasal process into medial nasal & lateral nasal process, which give rise to external nasal skeleton Olfactory placode deepens into olfactory pit & later olfactory sac which forms nasal cavities Nasal septum develops from mesodermal tecto- septal expansion from Rathkes pouch
Nasal Bone Frontal Process of Maxilla Upper Lateral Nasal Cartilage Lower Lateral Nasal (Alar) Cartilage Septal Cartilage Lesser Alar (Sesamoid) Cartilages
Internal Nose Openings: Anterior nares & posterior nares (Choanae). Vestibule of nose: lined by skin Nasal cavity proper: Lateral Wall Medial Wall (Septum) Roof Floor
Lateral Nasal Wall bony conchae covered with mucosa to form turbinates. Space below & lateral to turbinate is called meatus. Middle meatus contains a round bulla ethmoidalis separated from uncinate process by hiatus semilunaris that leads to a funnel shaped ethmoidal infundibulum.
Meatal Drainage 1. Inferior meatus: Nasolacrimal duct ( guarded at its end by a mucosal valve called HASNERs valve ) 2. Middle meatus: a. Frontal b. Anterior ethmoid c. Maxillary (natural + accessory ostia) 3. Superior meatus: Posterior ethmoid 4. Spheno-ethmoidal recess: Sphenoid
Complex micro-architectural pathway in ethmoid labyrinth that drains anterior group of paranasal sinuses. Consists of: frontal recess + ethmoid infundibulum + hiatus semilunaris + uncinate process + bulla ethmoidalis + middle meatus. O.M.C. pathology leads to infection of all anterior paranasal sinuses (Naumann).
Variants in O.M.C. 1.Concha bullosa (pneumatized M.T.) 2.Paradoxically curved middle turbinate 3.Medially turned uncinate process 4.Large bulla ethmoidalis 5.Hallers cell in orbital floor 6.Agger nasi cell anterior to M.T. 7.Onodi Cell with dehiscent Optic Nerve 8.Mucosal pathology
Paradoxically curved M.T.
Medialized Uncinate Process
Large bulla ethmoidalis
Agger nasi cell
Onodi cell with dehiscent optic nv
Blood Supply 1.Sphenopalatine artery (main artery) 2.Greater palatine artery 3.Superior labial artery 4.Anterior Ethmoidal artery 5.Posterior Ethmoidal artery 1, 2, 3 & 4 form Kiesselbachs plexus over Littles area on anterior septum
Venous drainage Ethmoidal veins: ophthalmic veins cavernous sinus Sphenopalatine vein: pterygoid plexus maxillary vein Woodruffs venous plexus: present on lateral wall near posterior end of middle turbinate Retro-columellar vein: behind columella
Sensory Nerve Supply Long & short Nasopalatine nerves Greater palatine nerve Infra-orbital nerve branches Anterior ethmoidal nerve Olfactory nerve
Development of P.N.S. Appear first First X-ray appearance Reach adult size by MaxillaryAt birth4 mth15 yr EthmoidalAt birth1yr12 yr Sphenoid2 yr4 yr18 yr Frontal4 yr6 yr15 yr
Sphenoid Sinus Relations
Muco-ciliary blanket Goblet cells in nasal mucosa secrete a mucous blanket; moved backwards like a conveyer belt into nasopharynx. Consists of: Superficial mucous or gel layer Deep serous or sol layer