WINDSOR UNIVERSITYSCHOOL OF MEDICINE

Dr. SREEKANTH THOTA

DEPARTMENT OF ANATOMY

Nose

PTERYGOPALATINE FOSSA

The pterygopalatine fossa is a small pyramidal space inferior to the apex of the orbit.

It lies between sphenoid posteriorly and the posterior aspect of the maxilla anteriorly.

CONTENTS OF THE PTERYGOPALATINE FOSSA

Terminal part of the maxillary artery. Maxillary nerve

FORAMENS OF FOSSA

1. Sphenopalatine foramen 2. Infra orbital fissure and foramen 3.Alveolar foramen 4. Palatine canal 5.Palatovaginal canal 6. Foramen rotundum

MAXILLARY NERVE

PTERYGOPALATINE PART OF THE MAXILLARY ARTERY

NASAL CAVITIES

NASAL CAVITIES

The two nasal cavities are the uppermost parts of the respiratory tract and contain the olfactory receptors.

The anterior apertures of the nasal cavities are the nares, which open onto the inferior surface of the nose.

The posterior apertures are the choanae, which open into the nasopharynx.

WALLS OF THE NASAL CAVITY

Each half of the nasal cavity has a floor, a roof, a lateral wall, and a medial or septal wall.

FLOOR

The palatine process of the maxilla and the horizontal plate of the palatine bone

ROOF

The roof is narrow and is formed anteriorly beneath the bridge of the nose by the nasal and frontal bones, in the middle by the cribriform plate of the ethmoid, located beneath the anterior cranial fossa, and posteriorly by the downward sloping body of the sphenoid

LATERAL WALL

The lateral wall has three projections of bone called the superior, middle, and inferior nasal conchae .

The space below each concha is called a meatus.

MEDIAL WALL

The medial wall is formed by the nasal septum. The upper part is formed by the vertical plate of the ethmoid and the vomer.

The anterior part is formed by the septal cartilage.

The septum rarely lies in the midline, thus increasing the size of one half of the nasal cavity and decreasing the size of the other.

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ETHMOID BONE

The single ethmoid bone is one of the most complex bones in the skull.

It contributes to the roof, lateral wall, and medial wall of both nasal cavities, and contains the ethmoidal cells (ethmoidal sinuses).

PARANASAL SINUSES

There are four paranasal air sinuses-the ethmoidal cells, and the sphenoidal, maxillary, and frontal sinuses.

Each is named according to the bone in which it is found.

PARANASAL SINUSES AND THEIR SITE OF DRAINAGE INTO THE NOSE

Sinus Site of Drainage

Maxillary sinus Middle meatus through hiatus semilunaris

Sphenoidal sinuses Sphenoethmoidal recessFrontal sinuses Middle meatus via

infundibulumEthmoidal sinuses

Anterior group Infundibulum and into middle meatus

Middle group Middle meatus on or above bulla ethmoidalis

Posterior group Superior meatus

SINUSITIS

Because the paranasal sinuses are continuous with the nasal cavities through apertures that open into them, infection may spread from the nasal cavities, producing inflammation and swelling of the mucosa of the sinuses (sinusitis) and local pain.

Sometimes several sinuses are inflamed (pansinusitis), and the swelling of the mucosa may block one or more openings of the sinuses into the nasal cavities.

INFECTION OF THE ETHMOIDAL CELLS

Severe infections from this source may cause blindness because some posterior ethmoidal cells lie close to the optic canal, which gives passage to the optic nerve and ophthalmic artery.

INFECTION OF THE MAXILLARY SINUSES

The maxillary sinuses are the most commonly infected, probably because their ostia are commonly small and are located high on their superomedial walls.

When the mucous membrane of the sinus is congested, the maxillary ostia are often obstructed. Because of the high location of the ostia, when the head is erect it is impossible for the sinuses to drain until they are full.

INFECTION OF THE MAXILLARY SINUSES

RELATIONSHIP OF THE TEETH TO THE MAXILLARY SINUS

The close proximity of the three maxillary molar teeth to the floor of the maxillary sinus poses potentially serious problems.

During removal of a molar tooth, a fracture of a root may occur. If proper retrieval methods are not used, a piece of the root may be driven superiorly into the maxillary sinus.

A communication may be created between the oral cavity and the maxillary sinus as a result, and an infection may occur.

SPHENOIDAL SINUSES

Because only thin shelves of bone separate the sphenoidal sinuses from the nasal cavities below and hypophyseal fossa above, the pituitary gland can be surgically approached through the roof of the nasal cavities by passing first through the anteroinferior aspect of the sphenoid bone and into the sphenoidal sinuses and then through the top of the sphenoid bone into the hypophyseal fossa.

FORAMENS RELATED TO NASAL CAVITY 1. Cribriform plate 2. Sphenopalatine foramen 3. Incisive canal

ARTERIES

1. Sphenopalatine artery 2. Anterior and posterior ethmoidal

arteries 3. Greater palatine artery 4. The superior labial artery and the

lateral nasal artery originate from the facial artery on the front of the face.

EPISTAXIS

Epistaxis (nosebleed) is relatively common because of the rich blood supply to the nasal mucosa.

In most cases, the cause is trauma and the bleeding is from an area in the anterior third of the nose (Kiesselbach area).

Epistaxis is also associated with infections and hypertension. Spurting of blood from the nose results from rupture of arteries.

KIESSELBACH AREA OR LITTLE'S AREA

VEINS

veins that pass with branches that ultimately originate from the maxillary artery drain into the pterygoid plexus of veins in the infratemporal fossa.

veins from anterior regions of the nasal cavities join the facial vein.

INNERVATION

1. Olfactory nerve [I] for olfaction 2. Branches of the ophthalmic [V1] and

maxillary [V2] nerves for general sensation.