Nose and paranasal sinuses

Dr. Lubna Nazli

Objectives

• External nose • Nasal cavity : its boundaries• Lateral wall : structure, blood & nerve

supply, lymphatic drainage• Nasal septum : structure, blood & nerve

supply, lymphatic drainage• Paranasal sinuses :list of sinuses,

boundaries, relations, communications, blood & nerve supply, lymphatic drainage

External nose

• Bony :nasal bones, and the frontal processes of the maxilla

• Cartilaginous

Nasal cavity

• The nasal chambers are situated one on either side of the median plane.

• They open in front through the nares, and communicate behind through the choana with the nasal part of the pharynx.

Boundaries

• The roof of the nasal cavity is narrow from side to side, and may be divided, into sphenoidal, ethmoidal, and frontonasal parts, after the bones which form it.

• The floor is concave from side to side and almost horizontal antero-posteriorly; its anterior three-fourths are formed by the palatine process of the maxilla, its posterior fourth by the horizontal process of the palatine bone.

Lateral wall showing conchae

Lat wall

Nerve supply

Nerves of ordinary sensation are:

• nasociliary branch of the ophthalmic

• anterior alveolar branch of the maxillary

• nerve of the pterygoid canal

• nasopalatine, the anterior palatine, and nasal branches of the sphenopalatine ganglion

Special sensory : olfactory nerve

PARANASAL SINUSES

The paranasal sinuses of the nose are

frontal, ethmoidal, sphenoidal, and maxillary.

They are lined by ciliated mucous membrane directly continuous with that of the nasal cavities.

Frontal sinuses

Frontal Sinuses

• situated behind the superciliary arches.

• Each opens into the anterior part of the corresponding middle meatus of the nose through the frontonasal duct.

• Absent at birth, develop between the seventh and eighth years, but reach their full size after puberty

Ethmoidal sinuses

Ethmoidal Air Cells• consist of numerous thin-walled cavities situated in the

ethmoidal labyrinth.• They lie between the upper parts of the nasal cavities

and the orbits.• They are arranged in three groups, anterior, middle,

and posterior. • The anterior and middle groups open into the middle

meatus of the nose.• The posterior cells open into the superior meatus.• The ethmoidal cells begin to develop during fetal life.

Sphenoidal Sinuses

Sphenoidal Sinuses • contained within the body of the sphenoid. vary

in size and shape. • Each sinus communicates with the

sphenoethmoidal recess by means of an aperture in the upper part of its anterior wall.

• They are present as minute cavities at birth, but their main development takes place after puberty.

Maxillary Sinus Maxillary Sinus (antrum of Highmore)• the largest sinus of the nose, is a pyramidal cavity in the body of

the maxilla.

Boundaries :• Its base is formed by the lateral wall of the nasal cavity.• Its apex extends into the zygomatic process. • Its roof or orbital wall is frequently ridged by the infra-orbital canal• Its floor is formed by the alveolar process and is a little below the

level of the floor of the nose. • In its base is an opening through which it communicates with the

hiatus semilunaris (middle meatus)• The maxillary sinus appears by the fourth month of fetal life, but

does not reach its full size until after the second dentition. 

Applied anatomy

• Epistaxis

• Fracture of cribriform plate: anosmia & CSF rhinorrhea

• Deviation of nasal septum: trauma or congenital

• Sinusitis