Sinuses develop as evaginations of the nasal mucosa. Consequently they have mucous membrane that is continuous with the nasal mucosa.
Newborns generally do not have sinuses.
Mucous can buildup in the sinuses from swelling, this tends to plug the area around the opening of the sinuses into the nose (i.e. the Middle Meatus) and impede on the passage of air through the nose as well.
Cilia of mucosal cells will trap particles in the air as it passes through the turbinates (conchae).
The cilia push the mucous toward the nasopharynx, and we end up swallowing the stuff.
If there is overload, the cilia can't push all of it and we get a runny nose.
The Four Sinuses:
FUNCTIONS OF THE AIR SINUSES
1. They lighten the skull & help to reduce the amount
of cortical bone. 2. Gives resonance to voice. 3. Increases surface area for tooth eruption. 4. Facilitates rapid growth of facial skeleton after birth,
mainly the maxillary bone. Clinically the air sinuses are divided into two groups. 1. Anterior group: Frontal, maxillary and anterior
Maxillary Sinus -- the only sinus whose opening is superior to the sinus itself, such that it can't easily drain into the nose due to gravity itself.
This is why, when you lay on one side of your body with a cold, you tend to clog the "downhill" side of your nose.
DIAGNOSTIC METHODS IN DISEASES OF THE SINUSES.
1 .ELICITING SINUS TENDERNESS:
2. TRANSILLUMINATION: In maxillary and frontal sinusitis.
3. RADIOLOGICAL EXAMINATION.
4. DIAGNOSTIC PROOF PUNCTURE.
5. SINOSCOPY: Using a fibre optic sinoscope. Detects early pathology, particularly malignancy. Done through intranasal anterostomy.
6. ECHOSINOGRAPHY : Detects sinus pathology by ultrasound.
7. CT SCAN : Confirmatory.
To detect obstruction of the sinuses or openings to the sinuses that may result from an allergic reaction.
How it works
Since light is able to pass through the delicate skin covering the hollow sinus cavities, a light source held against the upper cheek will produce a red dot on the palate if the sinuses are normal (filled with air rather than obstructed).
The NURSE presses the light source against the patient’s upper cheek, close to the nose, asks him to open his mouth widely, and looks at your palate to see if the light passes through.
Factors affecting results
The presence of fluids, pus, or other debris in the sinus cavities.
If the sinus cavities are obstructed (by a tumor, infection, or inflammation due to an allergic reaction), no red dot will be seen. X-rays or other tests must be performed to establish the cause.
It's simple, quick, and noninvasive.
It detects obstruction of the sinuses but not its cause.
Transillumination of Frontal sinus
Transillumination of Maxillary sinus
2 .ELICITING SINUS TENDERNESS:
Frontal sinuses are palpated by pressing the finger superiorly at the medial end of the superior orbital margin.
Ethmoidal sinuses are palpated with the thumb in the inner canthus of one eye and the index finger in the other and pushing posteriorly, posterior to the lachrymal bone and squeezing.
Normal findings: non-tender
Deviations: pain; discomfort
Percuss sinuses for resonance
Normal findings: hollow tone elicited; painless
Deviations: flat dull tone elicited; expresses pain