ANATOMY OF PARANASAL SINUSES

PRATYUSH KUMAR

objectives

• To know anatomical location• Their connections &

significance• Development• Neurovascular supply• Applied anatomy

Introduction

• Air containing cavities.

• Each sinus are named after the bone it resides in.

• 4 pairs :-• frontal • maxillary, ethmoidal,

sphenoidal

Anterior and lateral view

Maxillary sinuses

• Largest pns• Pyramidal in shape, • base pointing to

lateral wall of nose• Apex laterally in the

zygomatic process• Capacity 15 ml

Relations

• Anterior:- facial surface of maxilla

• Posterior:-infratemporal and pterygopalatine fossa

• Medial:- middle and inferor meatus

• Floor:- alveolar and palatine processes of maxilla

• Roof:-floor of orbit

• Blood supply : Facial, infra orbital, greater palatine arteries.

• Lymphatic drainage : Submandibular nodes.

• Nerve supply : Infra orbital, anterior, middle and post superior alveolar nerves.

Frontal sinus

• Resides in frontal bone

• 2nd largest• Asymmetrical• Usually paired-

sometimes one, three or none!

Relations

• Anterior:- skin over the forehead

• Inferior:-orbit & its contents

• Posterior:- meningeal and frontal lobe of brain

Neurovascular supply

• Blood supply - Supra orbital arteryAnterior ethmoidal arteries.

• Venous return - Anastomotic veins in supra orbital notch, connecting supra orbital and supra ophthalmic veins.

•  Lymphatic drainage - Submandibular nodes.

• Nerve supply - Supra orbital nerve traversing the floor of the sinus.

Ethmoidal sinuses

• Resides in ethmoid bone

• 3 groups:- anterior , posterior , sphenoethmoidal recess

• Number varies from 3-18

• Present from birth

Relation

• Roof:- anterior cranial fossa

• Lateral:- orbit (separated by lamina papyracea)

• Optic nerve lies close to posterior ethmoidal cells

Neurovascular supply

• Blood supply : Sphenopalatine artery Anterior and posterior ethmoidal artery.

• Lymphatic drainage : Submandibular nodesRetropharyngeal nodes. 

• Nerves : Anterior and posterior ethmoidal nerves.Orbital branches of pterygopalatine ganglion..

Sphenoid sinus

• Resides in body of sphenoid

• Maybe single or paired

• Asymmetrical• Not present at

birth

Relation

• Lies below to sella turcica• Sphenoid effusion shows skull

base fracture• Related to optic tract,chiasma,

internal carotid artery

• Blood supply : Posterior ethmoidal artery.

• Lymphatic drainage : Retropharyngeal nodes.

• Nerve supply : Posterior ethmoidal nerve.

Microscopic anatomy

• Lined by mucus membrane

• Ciliated columnar epithelium

• goblet cells secretes mucus

• Cilia are more marked near ostia.

Development

• Outpouching from mucus membrane of nose

• at birth:-Maxillary and ethmoidal present

• At 6-7 yrs:- frontals and sphenoids

• At 17-18 :- all full developed

Drainage