Paranasal sinuses anatomy

Question 1

What are the two subgroups of paranasal sinuses?

And what is the border of anterior from posterior ethmoid air cells?

Answer 1

• Anterior group (anterior ethmoid air cells, frontal sinus, maxillary sinus)
• Posterior group (posterior ethmoid cells, sphenoid sinus)

Basal lamella

Question 2

Is imaging needed in acute sinusitis?

Indications for CT

Answer 2

No imaging is needed unless complications

Pt not responding to treatment
Chronic/recurrent sinusitis
Pre-FESS work up
Complications of sinusitis (MR)

Question 3

Relationship of turbinates and meati

Answer 3

• Inferior meatus between inferior turbinate and middle turbinate
• Middle meatus between middle and superior turbinate
• Superior meatus above superior turbiate.

Question 4

Where do the anterior group of sinuses drain?

Where do the posterior group of sinuses drain?

Where is the nasolacrimal duct?

Answer 4

Middle meatus

Superior meatus

Inferior meatus

Question 5

Name the drainage pathways of the sinuses

Answer 5

• Ethmoid infudibulum - Maxillary sinus
• Frontal recess - Frontal sinus
• Spheno-ethmoid recess - Sphenoid sinus + Post. Ethmoid cells

Ostiomeatal complex - Frontal, Ant Ethmoid, Maxillary

Question 6

What seperates the anterior from the posterior ethmoid air cells?

Answer 6

The basal lamella (middle turbinate)

Question 7

Name the 5 patterns of rhinosinusitis

Answer 7

1. Spheno-ethmoid (opacif sphenoid and post ethmoid)
2. Infudibular (opacif maxillary sinus)
3. Ostiomeatal (frontal sinus, ant. ethmoid cells and maxillar sinus)
4. Nasal polyposis(inflammatory, bilateral)
5. Sporadic

Question 8

Name the structures in the osteomeatal complex

Answer 8

Maxillary ostium
Ethmoid infudibulum
Uncinate process
Hiatus semilunaris
Middle meatus

Question 9

FESS type of ectomies

Answer 9

Uncinectomy (uncinate process) + antrostomy

Conchectomy (resect middle turbinate)

Ethmoidectomy (ant. ethmoid air cells

Frontal sinusotomy (frontal recess)

Question 10

Name anatomic variants that can narrow the OMC outflow

Answer 10

Adherent uncinate process & maxillary atelectasis

1. Septal deviation
2. Concha Bullosa
3. Haller Cell (anterior ethmoid cell below orbit)
4. Paradoxical concha media

Question 11

Name anatomic variants that can narrow the frontal recess outflow

Answer 11

1. Agger Nasi cell (The most anterior ethmoid cell located below the frontal recess)
2. 1 cell above ANC type 1
3. > 2 cells above ANC type 2
4. 1 cell above ANC into frontal sinus type 3

Question 12

What does the mnemonic CLOSE refers to in preoperative sinus CT

Answer 12

Cribriform plate

Lamina papyracea

Onodi Cell

Sphenoid pneumatisation

Ethmoidal artery

Question 13

Does the depth of the olfactory fossa matter?

Answer 13

Yes, the deeper the olfactory fossa the highest risk of injury of the lateral lamella and CSF leak III>8mm

Question 14

Name the structures in the floor of the olfactory fossa

Answer 14

Middle: Crista galli

Floor: Cribriform plate

Lateral: Lateral lamella + fovea ethmoidalis

Question 15

Injury to lamina papyracea may cause

Answer 15

Orbital infection
Medial rectus injury
Orbital hematoma
Loss of vision

Question 16

What is an onodi cell?

Answer 16

Variant posterior ethmoidal cell
Superiorly of the sphenoid sinus
Horizontal septum
Associated with CNII dehiscence

Question 17

Supraorbital pneumatization is risk factor for injury of which artery?

Answer 17

Anterior ethmoidal artery

Question 18

Sphenoid sinus pneumanatization is a risk for which structures

Answer 18

Optic nerves
ICA
V2 Maxillary n.
Vidian nerve

Question 19

Which sinuses use the drainage of the ostiomeatal complex?

Answer 19

Maxillary sinus
Anterior Ethmoid cells
Frontal sinus
-> OMC -> Middle meatus

Question 20

Which sinuses should not have mucosal thickening?

Answer 20

Frontal and sphenoid

Question 21

High density in the sinus?

Answer 21

• Chronid sinusitis
• Fungus
• Mycetoma (calcifications)
• Odontogenic material (calcifications)