Describe the anatomy osteomeatal complex.
The osteomeatal complex includes:
- Bulla ethmodalis
- Uncinate process
- Maxillary turbinate
- Ethmoid infundibulum.
It is important as ostium of frontal maxillary and anterior ethmoidal sinuses are present in this area.
Any anatomical variation mucosal swelling of osteomeatal complex can cause obstruction →stasis →repeated infection upstream sinuses.
- Largest, constant anterior ethmoidal cell
- If not pneumatized, it may remain like a solid bony prominence.
- It may extend superiorly to base of skull and posteriorly to ground lamella
Retrobulbar recess+suprabulbar recess= Lateral sinus of Grunwald.
Lateral→ lamina papyracea
superior→ skull base
Medially→Opens into middle meatus
- Small thin lamina of ethmoid bone
- Forms floor and medial wall of the ethmoidal influndibulum
- Sickle shaped structure running from anterosuperior → posteroinferior direction.
|2 borders||2 ends
|Posterosuperior: free, sharp and virus|| to anterior surface of bulla ethmoidals||Posteroinferior end: attached to inferior turbinate and divides lower membranous part of middle meatus into anterior and posterior fontanella.
|anteroinferior border: altache to lateral nasal wall.||Antero superior end: variable insection LP/skull base/MT accounts for the variation in the drainage of frontal sinus.
- Attach to the lateral wall through ground lamella.
- Anterior 1/3 lie on sagittal plane →lateral edge of cribriform plate.
- Middle 1/3 lie on frontal plane →Lamina papyracea
- Posterior 1/3 runs horizontally →LP +medial wall of maxillary rimus.
- Fracture of Middle Turbinate can damage cribriform plate and cause CSF rhinorrhea and anosmia
- Paradoxical Middle Turbinate can narrow middle meatus and affect ventilation
- Concha bullosa (pneumatization of MT): 30%
- Usually asymptomatic
- drains into the frontal recess directly through agger nast cells
- affect ventilation of OMC and resuts s/s.
Hiatus semilunaris: 2 dimentional gap b/w Uncinate process and Bulla Ethmoidalis .
Opens laterally into 3 dimentional funnel shaped face called enthmoidal influndibulum.
Frontal sinus →opens into the anterosuperior part of infundibulium just posterior to posterior wall of agger nasi cell.
Anterior ethmoidal opens into infundibulum
- Natural ostium: opens in posterior infundibulum
- Accessory ostium: 4-5% in normal but increased to 25 % in Chronic rhinosinusitis
- Functional endoscopic sinus surgery(FESS) puts stress on this Osteomeatal comlex (OMC) and aims to restores normal sinus drainage and ventilation.
Tags: CSF Rhinorrhoea
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, Middle Turbinate
, osteomeatal complex.