Chapter 22 - Sinonasal anatomy/embryology/radiology Flashcards
Preferred method of evaluating sinonasal anatomy
CT triplanar recon
Epithelium lining sinuses
pseudostratified ciliated columnar (respiratory)
Direction cilia beat
Beat mucous toward natural ostium, and from there, to nasopharynx
Theories of function of sinuses
lighten skull
vocal resonance
absorb mechanical force during trauma to protect eyes/brain
produce/resevoir NO may regulate pulmonary fxn
Medial boundary and drainage of posterior ethmoid cells
superior turbinate
superior meatus
Onidi Cell
Sphenoethmoidal air cell
Gestational age when sinuses begin to develop
3rd fetal month
When sinuses grow
Maxillary: as face grows, significantly after permanent dentition
Ethmoid: also present at birth, grow until age 12
Frontal: rapidly pneumatizes in second decade, final size by end of this decade
Sphenoid: not much development until 7 yo, final size during adolescence
Main function of MRI in sinus eval
Diff secretions from neoplasm
Structures making up OMU
Ethmoid bulla (largest anterior ethmoid cell) Uncinate (ant to bulla) Ethmoid Infundibulum (trough between uncinate, lateral wall) Hiatus Semiluminaris (gap between bulla, uncinate, leads to infundibulum)
Agger Nasi
Area in lateral wall projects medially, superior to middle turbinate’s ant/sup attachment, commonly pneumatized
Typical size of ostium
1-3mm
Sinus drainage into nasal cavity
Max: to ethmoid infundibulum, then mid meatus
Frontal: ethmoid infundibulum
If uncinate attaches to lamina, then drains directly into middle meatus
Sphenoid: into sphenoethmoidal recess (between ST, septum)
Ethmoid: Mid Meat (ant), sup meat (post)
Haller cells
Infraorbital ethmoid
may narrow infundibulum
Frontal Recess Boundaries
Ant: Agger Nasi Post/Sup: Anterior fossa cranial base Medial: Mid Turb Lateral: Lamina Posterio/Inf: Ethmoid Bulla
Kuhn Classification for ethmoid cells within frontal drainage
1- single sup to agger nasi
2- >1 sup to agger nasi
3- extend into frontal sinus
4- isolated within frontal sinus
Describe blood supply to nose/sinus
A/P ethmoid: ethmoid, sup septum. br of ophthalmic
SPA: br max, one br passes inf to sphenoid ostium (post septum supply), another enters into middle turbinate, has small br for nasal floor, inf turb
Venous drainage sinuses
PPF, to cavernous sinus (lat to sphenoid sin)
Frontal sinus drains intracranially through vv perforate posterior table
5 lamellas in sinus surgery
1- Agger Nasi (ascending), Uncinate (descending)
2- bulla ethmmoidalis
3- basal lamella MT (border a/p ethmoids)
4- sup turb
5- fusion of 5th/6th ethmoturbinals, supreme turbinate
What to evaluate on CT prior to FESS
inflammation, sinuses/OMU Lamina integrity Cribiform depth/symmetry Ethmoid SB integrity Anterior ethmoid a location (SB or inferior) Onidi cell Optic nerve/ICA
