Nose and paranasal sinuses

Ehab ZAYYAN, MD, PhD

External nose

• Root and tip• Nostrils (nares): are the external orifices of

the nose. Bounded laterally by the ala and medially by the nasal septum

Nasal skeleton: • Nasalis bones • Frontal processes of the maxillae • Nasal part of the frontal bone • Upper and lower nasal cartilages • Septal cartilage

Nasal cavity

• From the nostrils till the choana

• Divided into right and left by the nasal septum

• Floor: palatine process of the maxilla and horisontal plates of the palatine bones

• Roof: body of the sphenoid, cribriform plate of the ethmoid, frontal bone, nasal bone, nasal cartilages

Lateral nasal wall

• Superior, middle and inferior conchae. The area below each concha is called meatus

Meatus Sinuses

Superior meatus Sphenoid sinus

Posterior ethmoid cells

Middle meatus Frontal sinus

Maxillary sinus

Anterior ethmoid cells

Inferior meatus Nasolacrimal duct

Nasolacrimal duct

• The middle meatus is continuous in front with a depression called the atrium.

• Within the nostril in front of the atrium is the vestibule. It is lined by modified skin and short curved hair called the vibrissae

MEDIAL NASAL WALL

Medial nasal wall

• The mucous membrane lines the nasal cavity except the vestibule. There are two types of mucous membranes:

1. Olfactory mucosa

2. Respiratory mucosa

1. olfactory mucous membrane: lines the superior surface of the superior concha and the sphenoethmoidal recess. It also lines the corresponding part of the nasal septum

• The axons of the fibers pass through the openings in the cribriform plates of the ethmoid bone and end in the olfactory bulb

2. The respiratory mucous membrane:

• Lines the rest of the nasal cavity.

• Its function is to warm, moisten and clean the inspired air.

• Warming: venous plaxus in the submucosa

• Moisture: mucous by the glands and goblet cells

• Ciliary action….

Nerve supply of the nasal cavity

• The olfactory nerve: arise from special olfactory cells in the olfactory mucous membrane

• Nerves of general sensation: derived from opthalmic and maxillary divisions of the trigeminal nerve:

• - anterior ethmoid nerve• - nasal, nasopalatine , greater and lesser

palatine nerves of the pterygopalatine ganglion

Sympathetic innervation:

• T1-T3 → SCSG → ICA plexus → deep petrosal nerve → vidian nerve → PPG

Parasympathetic innervation:

• Superior salivatory nucleus → facial nerve → GSPN → vidian nerve → PPG → nasal branches through the sphenopalatine foramen

Blood supply of the nasal cavity

ECA1. Sphenopalatine artery (maxillary artery)

2. Greater palatinal artery branch in the incisive canal (maxillary artery)

3. Superior labial branch of the facial artery

ICA4. Anterior ethmoid artery (ophthalmic artery)

5. Posterior ethmoid artery (ophthalmic artery)

Third part of the maxillary artery in the PPF

Kiesselbach area (Little area) of the nasal septum

• The area of the septum about 1 cm posterior to the nares. It is very rich in blood supply and a common site of epistaxis.

1. Anterior ethmoid artery

2. Sphenopalatine artery

3. Greater palatinal artery

4. Septal branch of facial artery

Anterior rhinoscopy

Posterior rhinoscopy

Paranasal sinuses

• Cavities found in the interior of the maxilla, frontal,sphenoid and ethmoid bones.

• Lined with mucoperiostium and filled with air.

• The mucous produced by the glands in the mucous membranes is moved into the nose by the ciliary action of the columnar cells.

• The function of the sinuses is to act as resonators of the voice and to reduce the weight of the skull.

Paranasal sinuses

Osteomeatal complex

• The most commonly infected structure in the sinuses

• Can be obstructed and inflammed easily with even minimal edema

• Can not be examined by anterior rhinoscopy but with endoscopy

• Can not be evaluated by conventional radiology but needs CT

Anatomic variations

Foreign body

Mucociliary dysfunction

Allergy

Infections

Local inflammation

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Obstruction of the osteomeatal complex

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Sinusitis

FESS

The target of Functional Endoscopic Sinus surgery (FESS) is to remove the pathology of the osteomeatal complex to maintain normal ventilation and drainage to the sinuses.