Lateral Wall Of Nose 5g4g6k

ANATOMY OF LATERAL WALL OF NOSE

EMBRYOLOGY IN BRIEF

 The development of NOSE starts at about 4th week of gestational age.  Three prominences appear around stomatodaeum(future mouth)….

FRONTONASAL PROCESS…mesoderm covering the developing forebrain Proliferates,& forms downward projection that overlaps upper part of stomatodaeum. MANDIBULAR ARCHES( Rt & Lt)….arising from 1st pharyngeal arch. Mandibular arch divides into maxillary and mandibular process.

4th-5th week

 The Nose is derived from frontonasal process in 4th fetal week.  5th fetal week ectodermal plaques develop on lateral aspect of FNP

& become paired NASAL PLACODES,early precursors of nares.  End of 5th week these convex placodes develop into concave nasal

grooves, the medial & lateral sides of placodes protrudes forwards to become Medial & Lateral Nasal Process.

• 6th fetal week nasal grooves become blind-ending Nasal Pits with forward & downward growth of maxillary process.

• 7th fetal week nasal pit deepens forms Nasal Sac which forms future nasal cavity.

6th -7th week

LATERAL WALL OF NOSE devolopment…. 7th-8th fetal week lateral wall of nasal capsule begins to form

series of ridges of mesenchymal tissue. st th 1 ridge, the maxilloturbinal(7 week)…INFERIOR TURBINATE. st th 5 to 6 ridges appear superior to 1 (8 week)…through regression & fusion, these ridges forms 3 to 4 ethmoturbinals.

• 1st ethmoturbinal (nasoturbinal)…aggar nasi (ascending portio & uncinate process(descending portion). • 2nd ethmoturbinal ….MIDDLE TURBINATE. • 3rd forms …SUPERIOR TURBINATE • rest regress or supreme turbinate.

8th week

SUMMARY OF EMRYONIC PRECURSORS

PARANASAL SINUSES Appear as outgrowths from nasal cavity.

Frontal ,maxillary,& ethmoidal sinuses arise from

evaginations of lateral nasal wall. Sphenoid sinus arises from a posterior evagination of nasal capsule.

PARANASAL SINUSES The sinuses begin to develop in 3rd fetal month & only

ethmoidal & maxillary sinus, are present at birth. Maxillary sinus begins as an outpounching of lateral nasal wall at 10th fetal week. Ethmoidal sinus begins at 3rd month of fetal life.

 Frontal sinus develops during 4th fetal month as an

outpounching medial the most superior aspect of uncinate process.  Sphenoid sinus are unique in that they arise from within the nasal capsule of embryonic nose. undeveloped until 3 yrs by 7 yrs pneumatization reaches sella tursica by age 9 to 12 it is generally complete

Lateral nasal wall  Formed by 3 or 4 conchae(or turbinates)  Named from below inferior, middle, superior, supreme conchae.  Meatus refers to air spaces located beneath conchae  Remaining nasal cavity posterior to turbinates is nasopharyngeal

meatus.

 The lateral wall of nose:  Maxillary bone  Ethmoid bone  sphenoid bone  Inferior turbinate  Lacrimal bone  Palatine bone

Turbinates

Lamella

Lateral nasal wall Inferior turbinate/meatus  Largest turbinate and largest meatus  Highest at the jnctn of ant and middle 3 rd (1.6-2.3 cm)  Separate bone covered by thick mucous membrane  Nasolacrimal opening in anterior portion of lateral wall of inferior meatus  Slit like opening is protected by fold of mucous membrane, the plica lacrimalis or valve of Hasner

Lateral nasal wall Inferior turbinate  separate bone with irregular surface ,perforated and grooved by vascular channels…  has a maxillary process which articulates with inferior margin of

maxillary hiatus,  articulates with ethnoid, palatine and lacrimal bones.

Middle turbinate/meatus  Portion of ethmoid bone  It recieves drainage from the frontal, maxillary and ant ethmoidal cells  hiatus semilunaris and ethmoid infundibulum.  maxillary hiatus.  ant and post fontanelles  recesses terminalis

The agger nasi  remnant of the nasoturbinal in lower mammals  most anterior part of the ethmoid.  Represented by small crest or mound on the lateral wall just ant to attachment of middle turbinate.  it may be pnuematised ( 5 – 80 % )

Middle turbinate, basal lamella Part 1st part 2nd part 3rd part

Site Direction (anterior) Vertical (middle) Oblique (posterior) Transverse

Attachment Skull base Lamina papyracea Perpendicular plate of palatine bone

Basal lamella and ethmoids •

Basal lamella: – Anterior ethmoids – Posterior ethmoids

Uncinate process

Ethmoidal bulla  Contains largest ant etmoidal cell  Ant face forms the posterior margin of HS  Post – fuse with basal lamella of the MT  Superiorly – reach the roof of ethmoids forming post wall of frontal recess.  retrobullar recess  Suprabullar recess

Concha bullosa:(36%)

 Aerated middle turbinate/unilateral or bilateral  May obstruct middle meatus osteomeatal complex(sinusitis)  May get infected form mucocele

Paradoxical middle turbinate:

 Greater curvature of middle turbinate is concave to

middle meatus

Double middle turbinate:  Anteriorly bent UP may come in with middle

turbinate  Narrows middle meatus & appear as additional turbinate

Frontal recess

A

B

Opening of the frontal sinus  Drainage into frontal recess anterior to the infundibulum(55%)  Drainage above but not into the infundibulum(30%)

 Drainage into infundibulum(15%)  Drainage above the bulla(1%)

Uncinate process

Ostiomeatal complex : OMC

Anterior ethmoid middle meatus complex

Ostiomeatal complex : OMC Suprabullar recess Lateral sinus Retrobullar recess

Maxillary ostium

Frontal ostium Frontal recess

Infundibulum

Ostiomeatal complex : OMC  Bulla ethmoidalis  Hiatus semilunaris inferior  Infundibulum

Frontal recess & Frontal ostium  Maxillary ostium 

Maxillary ostium

Superior turbinate/meatus  Is approx. ½ length of middle turbinate  Starts about middle of lower turbinate & becomes

continuous with them  Sphenoethmoidal recess opens medial to superior turbinate

supreme turbinate  Unilaterally or bilaterally in 60% of individuals  Ostia of pos. ethmoidal cells open into supreme meatus(75%)

APPLIED ANATOMY OF LATERAL WALL OF NOSE ……..mainly during endoscopic surgery

Skull base: anterior ethmoids & AEA  Crista galli  Septum  Cribriform plate  Middle turbinate  Lateral lamella  Fovea ethmoidalis

Sphenoid sinus  Optic nerve

 Carotid artery  Sella tursica  Maxillary nerve  Vidian nerve

Blood Supply  The arterial supply is from external and internal carotid.  Majority from branches of the maxillary artery, one of the

terminal branches of the external carotid artery  The most important branch is the sphenopalatine artery

Blood Supply  Sphenopalatine enters via sphenopalatine foramen which lies just inf to the horizontal attachment of the middle turbinate  An area anteriorly is supplied by the branch from the facial

and part of the lateral wall adjacent to the palate recieves blood from greater palatine.  The internal carotid art via ethmoidals supply superior

lateral walls

Nerve Supply  Superior part – olfactory nerve.  Anterosuperiorly – ant ethm nerve  Post – branches of pterygopalatine ganglion ant pal nerves  Infraorbital nerve

 Ant sup alveolar n

Lymph Drainage  The lymph vessels draining the vestibule end in the

submandibular nodes  The remainder of the nasal cavity is drained by vessels that

to the upper deep cervical nodes

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