2009년 8월 ethmoid bone dissection-lateral nasal sinus anatomy

Ethmoid bone dissection

Anatomy of Lateral Nasal Wall and Sphenoid sinus

and surrounding structure

2009 년 8 월 4 일안 성 용

Nasal turbinate

Normal Anatomy

Paranasal sinuses ; frontal sinus, maxillary sinus, ethmoid sinus, sphenoid si-

nus

Normal Anatomy

The Ostiomeatal Complex(OMC) ; air cells of anterior ethmoid and ostia ; middle meatus ; final sections of the common drainage and ventilation

pathway of the frontal, maxillary, and anterior ethmoid si-nuses

Normal Anatomy

The Ostiomeatal Complex(OMC) 2 - Agger nasi cell - Uncinate process - Bulla ethmoidalis - Hiatus semilunaris inferior - Middle turbinate - Maxillar sinus ostium - Frontal sinus ostium

Normal Anatomy

Agger nasi cell - located medial to lacrimal sac and fossa anterior to the uncinate process - product of pneumatization of the lacrimal bone

Ethmoid sinus anatomy

Uncinate process ; sickle-shaped, thin, bony plate ; attachment anterior : anterosuperiorly, attached to the MT : form the inferomedial wall of agger nasi cell inferior : inferior turbinate and palatine bone posterior : parallel to the curvature of bulla ethmoidalis superior : attach to lacrimal bone base of the skull or LP always fuses with the MT anterosuperiorly


Uncinate process 2


Middle turbinate - conchal head, conchal neck, conchal sinus - conchal sinus, cavity between ethmoid bulla and MT - 3 discernible component 1st. Part ; anterior and medial position, sagittal plane attach vertically to the skull base, LT, lateral

lamella 2nd. Part ; frontal plane attach laterally to the lamina papyracea in an oblique fashion 3rd. Part ; (basal lamella) horizontal plane attach laterally to the perpendicular plate of pala-

tine


Middle turbinate 2


Three part Plane Attachment

Anterior 1/3 Vertical(Sagittal plane)

Crista ethmoidalis and the skull base

Middle 1/3 Oblique(Frontal plane)

Lamina papyracea

Posterior 1/3 Horizontal plane Lamina papyracea & lamina perpen-dicularis

Basal lamella 1st. Uncinate process 2nd. Bulla ethmoidalis 3rd. Basal lamella of the middle turbinate 4th. Lamella of the superior turbinate 5th. Lamella of the supreme turbinate


Bulla Ethmoidalis - most constant landmark - Boundary anterior ; convex curvature posterior free border of UP superior ; Fovea posterior ; basal lamella(variable) lateral ; lamina papyracea medial ; covered by middle turbinate


Hiatus Semilunaris Inferior - sickle-shaped 2D cleft - average width, 1.5mm - between the ethmoidal bulla and free edge of uncinate

process


Ethmoid infundibulum - well-defined 3D cleft between anterior wall of ethmoidal bulla and posterior wall of uncinate process - medial ; uncinate process lateral ; formed by LP, frontal process of the maxilla depth ; average depth, 2mm(variable, 0.5~10mm)


Hiatus Semilunaris Superior - between ethmoid bulla(anteriorly and inferiorly) and skull base(superiorly) and basal lamella(posteriorly)


Lateral sinus - not always present - boundary superior ; fovea inferior ; roof of the ethmoid bulla posterior ; basal lamella of the MT lateral ; lamina papyracea medial ; middle turbinate dorsal ; space between bulla ethmoidalis and basal lamella open ; between bulla ethmoidalis and middle turbinate


Lateral sinus 2 - divided into suprabullar recess and retrobullar recess a. suprabullar recess ; a space bordered by the ethmoidal

bulla(inferiorly) ethmoidal fovea(superiorly) b. retrobullar recess ; bordered by ethmoidal bullar(anteriorly) basal lamella(posteriorly)


Maxillary sinus ostium - usually located posterior and inferior at the angle

formed by the ethmoidal bulla and uncinate process


Fontanelle area - 2 distinct areas on the lateral nasal wall where the nasal muconsa and mucoperiosteum of the maxillary sinus

- anterior fontanelle : anterior and inferior to the inferior

attachment of the uncinate process - posterior fontanelle : superior to the posterior insertion

of the uncinate process


Frontal sinus ostium - located at the bulla-uncinate angle anteriorly and superiorly


Supraorbital Ethmoid air cell - arise from pneumatization of the orbital process of the

frontal bone(15~21%) - located just posterior to the frontal sinus ostium - AEA, just posterior to the supraorbital cell


Anterior Ethmoid artery - orbital branch of ophthalmic a. exit the orbit through ant. Ethmoidal foramen → pass into orbito-cranial canal in the roof of the ethmoid → enter the lateral lamella and olfactory fossa

cf. posterior ethmoid artery : ophthalmic artery : posterior ethmoid canal - optic foramen(5~10mm)


Posterior ethmoid cell - larger in size, fewer in number than the anterior ethmoid

cells - anterior ; basal lamella posterior ; anterior wall of sphenoid sinus lateral ; lamina papyracea medial ; superior meatus and superior turbinate superior ; fovea ethmoidalis inferior ; posterior part of middle turbinate


Sphenoethoidal cell(Onodi cell) - lateral and superior extension of posterior ethmoids - relation to the optic nerve and/or internal carotid artery


Roof of Ethmoids - anterior 2/3, frontal bone, fovea ethmoidalis - medially, join the lamina cribrosa - height of the roof(Keros)


Lateral lamella - thinnest at the location of anterior ethmoid arterial passage (0.05mm. 1/10 of thickness of fovea ethmoidalis)


Cribriform plate - perforated by the olfactory nerve fiber - attach to the crista gali and perpendicular plate middle turbinate lateral lamella


Olfactory fossa - located between the crista gali medially cribriform plate inferiorly lateral lamella laterally - olfactory bulb


Frontal recess - the space where the frontal sinus open - boundary anterior ; uncinate process and agger nasi cell posterior ; bulla ethmoidalis and suprabullar lamella lateral ; lamina papyracea medial ; hiatus semilunaris inferior or neck of MT inferior ; ethmoid infundibulum superior ; fovea ethmoidalis, supraorbital cell, anterior ethmoid artery, frontal ostium

Frontal sinus anatomy

Frontal recess


Frontal recess 2 - size of the frontal recess, determined by the size of the surrounding anterior ethmoid air cell(bulla ethmoidalis, agger nasi cell, supraorbital cell and frontal cells)


Frontal cells - Kuhn type I : a single small cell above the agger nasi cell II : multiple small cells above the agger nasi cell III : a single large cell above the agger nasi cell extend-

ing to the frontal sinus IV : a single small cell inside the frontal sinus


Spatial relationship - superior ; anterior cranial fossa - anterior ; spheno-ethmoid recess, superior turbinate, and posterior ethmoid - inferior ; nasopharynx - posterior ; basi-sphenoid sella posterior cranial fossa - lateral ; middle cranial fossa, cavernous sinus

Sphenoid sinus anatomy

Classification : basis of pneumatization - conchal(2~3%) - presellar(11%) - sellar(86%)


Neurovascular relationship - optic nerve - internal carotid artery - maxillary nerve(V2) in the foramen rotundum - Vidian nerve in the pterygoid canal


Sphenoid sinus ostium - 1~5mm in size - round, oval or vertical cleft - located just medial to the posterior end of the superior turbinate - close to the midline in the anterior sphenoid wall at the junction of the upper 1/3 and lower 2/3


Supraoptic and Infraoptic recess - pnumatization extends into the lesser sphenoid wing (size and depth, degree of pneumatization of the anterior

clinoid process)


Sphenoid rotrum - midline projection of anterior sphenoid wall - articulate, perpendicular plate of ethmoid and vomer


Sphenoethmoid recess - a space behind and above the most superior

turbinate - boundary superior ; cribliform plate

inferior ; nasopharynx anterior ; uppermost concha (superior or supreme turbinate) posterior ; anterior wall of sphenoid sinus medial ; nasal septum


Cavernous sinus - CN III, IV, V, VI - carotid artery


- Reference

1) N.J. Bhatt Endoscopic Sinus Surgery new horizons p.48~51 2) 이비인후과학 두경부외과학 3) R. Kamel. Endoscopic anatomy of the lateral nasal wall, ostiomeatal complex and anterior skull base