Sinus Flashcards
What percentage of people fail to develop frontal sinuses?
4%
Which four sinuses are present in the head and neck?
Maxillary
Frontal
Sphenoid
Ethmoid
Which sinus the the first to develop?
Maxillary
What pattern of growth does the maxillary sinus undergo?
It is present at birth and rapid growth during primary teeth
By age three it is half adult size and reached full size by 23
15ml volume for adults
What percentage of maxillary sinuses have septa?
8.5%
What percentage of maxillary sinus have hyperplasia
Less than 1%
What percentage of maxillary sinus have aplasia?
1%
What percentage of maxillary sinus are hypo plastic?
- 7% unilateral
7. 2% bilateral
What forms the posterior wall of maxillary Antrum?
Pterygopalatine fossa
Where does the sphenoid sinus drain into?
The sphenoethmoidal recess
Where does the posterior ethmoidal sinus drain into?
Superior meatus
Where does the frontal maxillary and ant and middle ethmoidal sinus drain into?
The middle meatus
Where does then asp lacrimal duct drain into?
The inferior meatus
What is concha bullosa?
This is when the middle concha becomes pneumatised and blocks the ostium
What techniques are available to image the maxillary Antrum?
Plain films : OM/IO films for floor of Antrum, DPT for medial and posterior and lateral walls
CT/CBCT/MRI
When using plain films for the sinus what should you look for?
Opacity within the Antrum
Alteration in wall integrity or outline
Foreign bodies
What are the three main groups of antral diseases?
Developments
Aquired
Other
Which developmental diseases of the sinus are there?
Hyperplasia
Aplasia
Hypoplasia
What aquired diseases of the Antrum are there?
Inflam and polyps
Trauma
Cysts
Neoplasms
What other diseases can affect the sinus?
Paget’s disease
Thalassemia
Fibrous dysphasia
Osteopetrosis
What Inflam changes do you see in the sinuses following infection?
Thickening of more than 3mm Fluid level Polyps Empyema Mucous retention cyst
Mainly seen with bacterial and fungal not viral!
A patient aged less than 16 with pansinusitis. What would you be suspicious of?
Cystic fibrosis
When would you perform imaging techniques in a patent with Inflam of the sinuses?
Chronic sinusitis for more than 3 months
Consider CT
What would you see following inflammatory sinus disease on a radiograph?
Thickening of lining
Opacification
What would you see radiologically in a patient with chronic sinusitis?
Persistent opacification and sclerosis of the surrounding bone (hyperostosis)
A fluid level present in the Antrum. What could this be?
Blood
Pus
Exudate
What are polyps of the sinus associated with? What features can they have radiographically?
Inflammation
They may displace bone mimicking a tumour
What is an antral choanal polyp?
Polyp that arises from the maxillary Antrum and protrudes through the ostium into middle meatus
Then extends into the nasal cavity to the chona (boundary between nasal cavity and nasopharynx)
What types of cysts can affect the sinus?
Benign retention cyst
What are the features of these cysts?
Affects all ages (mainly 20-30 males)
Twice as common in females as males
1.4-13% incidence
Usually asymptomatic
What are the radiological features of a benign retention cysts?
Well defined Smooth outline Domed Same density through lesion Remaining sinus normal
What is a differential diagnosis of a sinus retention cyst?
Odontogenic tumour: but need a halo
Antral polyp: usually multiple, and heterogenous, thickened mucosal lining
What is a a mucocele?
Explainding lesion
Beings with a retention cyst which then blocks the ostium
The pressure then increases and bone becomes thinned down which can destroy the sinus bone
90% occur in ethmoidal or frontal sinus
Which fungal infection can affect the sinus?
Aspergillosis
What percentage of cysts of the Antrum are extrinsic to the Antrum?
50%
Radicular > den > kerato
What are the radiologic features of an odontogenic cyst within the sinus?
Halo effect
Base of Antrum
Domed opacity
Expansion of alveolus and displaced teeth occ
Large cysts may disrupt the antral lining
How can you differentiate between an odontogenic tumour and cysts own tin the Antrum?
The tumour may Resorb teeth and displace the teeth into the sinus
It expands and destroys sinus lining
Which tumours can affect the antral lining?
Osteoma and carcinoma
What age group are generally affected by Osteoma?
Males more than females
10-50 yrs
Maybe teeth or antrolith or mycolith
How common are antral carcinoma?
<1% of all malignancies
SCC carcinoma accounts for 80-90% of paranas sinus malignancies
Antral carcinoma is more common in who and and what age?
Makes more than females
>60 yrs
What should you do when there is an unexained radiopacity within the sinus?
Biopsy
What are the radiological features of an antral carcinoma?
Invaded walls
Non specific
Opacification in Antrum
Need CT/MRI
What are the borders of the maxillary Antrum?
Superior is orbit
Inferior is palate
Medial is lateral wall of nose
What is the lining of the maxillary Antrum?
Ciliated columnar
What are the causes of sinusitis?
Nasal infection Infection from teeth Infection from OAF Nasal allergy Blocked middle meatus
What is the pathology behind sinusitis?
Increased secretion from lining
Increased cliliary activity
Thickening of mucous membrane
Fibrosis
What are the acute symptoms of sinusitis?
Pain in upper teeth
Beating sensation behind cheek
Fullness below eyes
Nasal discharge
What are the symptoms of chronic sinusitis?
Incomplete resolution
Purulent nasal discharge
Recurrent sinusitis
OAF
How can we manage sinusitis?
Antrostomy
Decongestants and antibiotics
When does the frontal sinus begin to form and what is it lines by?
5 years
Lined by columnar epithelium
What are the symptoms of frontal sinus itis?
Frontal bone pain
Pain above eyes
Pulls on trochlea due to inflam: visual disturbances
Oedema of brow and upper eyelid
What are the complication of frontal sinusitis?
Can spread to cranium and eye
May lead to chronic problems eg polyp
Where are the ethnoidal air cells located?
Lateral wall of nose upper part
What are the margins of the sinus?
Lateral: orbit
Inferior: maxillary sinus
What is the ethmoidal sinus lines by?
Columnar ciliated epithelium
What are symptoms of ethmoidal sinusitis?
Pain behind eyes Tender medial canthus Spreads to involve the orbit And suboeriosteal swelling Maybe complete eye lid closure
Where is the sphenoid sinus located?
Body of sphenoid bone
What are the borders of the sphenoid sinus?
Lateral: cavernous sinus
Superior : pituitary
Floor: nerve of pterygoid canal
What are the symptoms of sphenoid sinusitis?
Pain in middle of skull and temporal region spreading down neck
