PARANASAL.html


    
        
            
                
                    

                

            

            
                Paranasal sinus variants

                Zaeem I Ebrahim, MB BCh
            

            Zarina I Lockhat, FFRad (D) (SA)
        

        Department of Radiology, University of Pretoria

        
            Corresponding author: Z Ebrahim (zaeem@iafrica.com)

            
            

            
                Abstract

                Normal
                variations of the the paranasal sinuses tend to be overlooked but can
                have pathological consequences, making identification important.

            

            
            

            Introduction

            The paranasal sinuses have many variations of their
            normal anatomy. The variants are usually revealed as incidental
            findings that are overlooked. The aetiology is congenital or
            developmental. Although the variations are normal, they can have
            pathological consequences, therefore making identification important.

            This pictorial essay was created from the records
            of patients attending Kalafong Hospital’s CT scanning department.
            The patients presented with pathology not related to the paranasal
            sinuses.

            Agger nasi cells

            The agger nasi cells (Latin for ‘nasal
            mound’) are the most anterior ethmoid cells. They are extramural
            cells (not confined within the ethmoid bone) and extend anteriorly into
            the lacrimal bone. They are anterior to the anterior attachment of the
            middle turbinate to the skull base. Viewed in the sagittal plane, they
            are located anteriorly and inferiorly to the frontal recess. On coronal
            CT, they appear as inferior to the frontal recess and lateral to the
            middle turbinate (Figs 1 and 2).

            The bulla ethmoidalis is a prominent anterior
            ethmoid air cell (Fig. 3). A degree of pneumatisation may vary, and
            failure to pneumatise is termed torus ethmoidalis.

            Haller cells are located below the bulla ethmoidalis and extend beneath the floor of the orbit (Figs 4 and 5).

            The intersphenoid septum is often deflected to one
            side, attaching to the bony wall covering the carotid artery (Fig. 6).
            This artery can be injured if the septum is avulsed during surgery.

            Pneumatisation of the uncinate process may be encountered in up to 4% of the population (Fig. 9).

            A concha bullosa is a pneumatised middle turbinate
            and has a reported prevalence of 34%. Concha bullosa is readily
            identified on CT (Fig. 10).

            
            

            1.	Dahnert W. Radiology Review Manual. 5th ed. Philadelphia, USA: Lippincott Williams and Wilkins, 2003.

            1.	Dahnert W. Radiology Review Manual. 5th ed. Philadelphia, USA: Lippincott Williams and Wilkins, 2003.

            2. Chong VFH, Fan YF, Sethi DS. Pictorial review functional endoscopic
            sinus surgery (FESS). Clinical Radiology 1998; 53(9):650-658.

            2. Chong VFH, Fan YF, Sethi DS. Pictorial review functional endoscopic
            sinus surgery (FESS). Clinical Radiology 1998; 53(9):650-658.

            3.	Weissleder R, Wittenberg J, Mukesh GH, et al. Primer of Diagnostic Imaging. Philadelphia, USA: Mosby Elsevier, 2011.

            3.	Weissleder R, Wittenberg J, Mukesh GH, et al. Primer of Diagnostic Imaging. Philadelphia, USA: Mosby Elsevier, 2011.

        

        
            

        

        
            
        

        
            Fig. 1. Agger nasi – left (X).

            
            

            
                
            

            
                Fig. 2. Agger nasi – sagittal (X).

                
                

                
                    
                

                Fig. 3. Bilateral bulla ethmoidalis (X)

            

        

        
            
        

        
            Fig. 4. Haller cells – left (arrow).

            
            

        

        

        
            
        

        
            Fig. 5. Haller cells – right (star).

            
            

        

        

        
            
            

        

        
            
        

        
            Fig. 6. Intersphenoid septum (arrow).

            
            

        

        
            
                

            

        

        
            
        

        
            Fig. 7. Pneumatised anterior clinoid process (star).

            
            

            
                
            

            
                Fig. 8. Pneumatised clinoid processes (star – anterior; triangle – posterior).

                
                

                
                    
                

                Fig. 9. Pneumatised uncinate processes, bilaterally (dots).

                
                

                
                    
                

                
                    Fig. 10. Bilateral concha bullosa (X).

                    
                    

                

                
                

            

        

        
            
                
            

            
                Fig. 11. Pneumatised superior nasal turbinate (arrow).