International Journal of Anatomy and Research

Welcome to International Journal of Anatomy and Research




Type of Article: Original Research

Year: 2016 | Volume 4 | Issue 3 | Page No. 2738-2742

Date of Publication: 31-08-2016



Pretty Rathnakar *1, Shrinath D. Kamath. P 2.

*1 Assistant Professor, Department of Anatomy, K.S. Hegde Medical Academy, Deralakatte, Mangalore, Karnataka, India.

2 Associate Professor, Department of ENT, K.S. Hegde Medical Academy, Deralakatte, Mangalore, Karnataka, India.

Address: Dr Pretty Rathnakar, Assistant Professor, Department of Anatomy, K.S. Hegde Medical Academy, Deralakatte, Mangalore, Karnataka, India.


Introduction: Variations in anterior skull base depth (depth of olfactory fossa) is common. The endoscopic surgeons should have knowledge about this. A coronal CT scan of paranasal sinuses (PNS) is mandatory prior to Functional endoscopic sinus surgery. The aim of this study was to calculate the depth of olfactory fossa and classify it according to that done by Keros. Comparison of Olfactory fossa depth was done among males and  females .
Materials and Methods: A retrospective study was conducted among 100 Dakshina Kannada patients .Coronal CT  scans of PNS were observed . The depth of the lateral lamella of cribriform plate (LLCP) was calculated by subtracting the depth of the cribriform plate from the depth of the medial ethmoid roof. The observations were classified according to Keros classification. Data was compared among males and females. Any asymmetry in the Ethmoid roof was noted.
Result: The mean LLCP height on the right side was 4.06 ± 1.283 mm and 4.44±1.313 on the left side. There is statistically significant difference in the height of lateral lamella between the right and left side independent of gender (P<0.05). However, there was no statistical significance in mean LLCP height in case of males and females. Ethmoid roof was found to be low more frequently on the left side, both in case of males and females.
Conclusion: Keros Type II class was more frequent in the present study .When compared with other studies variations have been observed in different populations. The anatomical variations of anterior skull base in each patient should be carefully evaluated preoperatively to avoid complica­tions during endoscopic sinus surgeries.
Key words: Olfactory Fossa, Anterior Skull Base, Lateral Lamella Of Cribriform Plate, Keros.


  1. Kennedy DW, Zinreich S J, Rosenbaum AE, Johns ME. Functional endoscopic sinus surgery. Theory and diagnostic evaluation. Arch Otolaryngol 1985;111:576-82.
  2. Kennedy DW. Senior BA. Endoscopic sinus surgery : a review . Otolaryngol clin North Am 1997;30:313-330.
  3. Wormald PJ. The anatomy of the frontal recess and frontal sinus with three dimensional reconstruction. In: endoscopic sinus surgery ,anatomy ,three dimensional reconstruction and surgical technique . Wormald PJ( eds). Thieme medical publishers, Newyork 2005;35-53.
  4. Stammberger H. Hawke M. Special endoscopic anatomy of the lateral nasal wall and ethmoidal sinuses. In :  Functional Sinus Surgery: the Messerklinger technique. Stammberger H eds. BC Decker ,Philadelphia  1991;49-87.
  5. Keros P. On the practical value of differences in the level of the lamina cribrosa of the ethmoid. Z Laryngol Rhinol Otol 1962;41:809-13.
  6. Bista M, Maharjan M, Kafle P, Shrestha S,KCT. Computed tomographic assessment of lateral lamella of cribriform plate and comparison of depth of olfactory fossa .J Nepal Med Assoc 2010;49(178):92-5.
  7. Elwany S, Medanni A, Eid M, Aly A, El-Daly A, Ammar SR. Radiological observations on the olfactory fossa and ethmoid roof. J Laryngol Otol 2010;124:1251-6.
  8. Salroo  N, Dar N H, Yousuf A, Lone K S.  Computerised tomographic profile of ethmoid roof on basis of keros classification among ethnic Kashmiri’s.  Int J Otorhinolaryngol Head Neck Surg. 2016 Jan;2(1):1-5.
  9. Solares CA, Lee WT, Batra PS, Citardi MJ. Lateral Lamella of the cribriform plate. Software-enabled computed tomographic analysis and its clinical relevance in skull base surgery. Arch Otolaryngol Head Neck Surg 2008;134:285-9.
  10. Souza SA, Souza MMA, Idagawa M, Wolosker AMB, Ajzen SA. Computed tomography assessment of the ethmoid roof: a relevant region at risk in endoscopic sinus surgery. Radiol Bras 2008;4:143-7.
  11. Erdem G, Erdem T, Miman MC, Ozturan O. A radiological ana­tomic study of the cribriform plate compared with constant structures. Rhinology 2004;42:225-9.
  12. Kaplanoglu H, Kaplanoglu V, Dilli A, Toprak U, Hekimoğlu B.An Analysis of the Anatomic Variations of the Paranasal Sinuses and Ethmoid Roof Using Computed Tomography.  Eurasian J Med 2013;45:115-25.
  13. Meloni F, Mini R, Rovasio S, Stomeo F, Teatini GP. Anatomic variations of surgical importance in ethmoid labyrinth and sphenoid sinus. A study of radiologic anatomy. Surg Radiol Anat 1992;14:65-70.
  14. Arslan H, Aydınlıoglu A, Bozkurt M, Egeli E. Anatomic variations of the paranasal sinuses :CT examination for endoscopic sinus surgery. Aurius Nasus Larynx 1999;26:39-48.
  15. Shama A.M.S., Montaser M. Variations of the height of the ethmoid roof among Egyptian adult population: MDCT study. The Egyptian Journal of Radiology and Nuclear Medicine 2015;46;929-936.
  16. Alazzawi S, Omar R, Rahmat K, Alli K. Radiological analysis of the ethmoid roof in the Malaysian population. Auris Nasus Larynx 2012;39:393-6.
  17. Krmpotic-Nemanic J, Vinter I, Judas M. Transformation of the shape of the ethmoid bone during the course of life. Eur Arch Otorhinolaryngol 1997;254:347-349.
  18. Dessi P, Moulin G, Triglia JM, Zanaret M, Cannoni M. Difference in the height of the right and left ethmoidal roofs: a possible risk factor for ethmoidal surgery. Prospective study of 150 CT scans. J Laryngol Otol 1994;108:261-2.
  19. Arikan OK, Unal B, Kazkayasi M, Koc C. The analsis of anterior skull base from two different perspectives: coronal and reconstructed sagittal computed tomography. Rhinology 2005;43:115-20.
  20. Lebowitz RA, Terk A, Jacobs JB, Holliday RA  Asymmetry of the ethmoid roof: analysis using coronal computed tomography.Laryngoscope 2001;111:2122-2124.


Pretty Rathnakar, Shrinath D. Kamath. P.COMPUTED TOMOGRAPHIC STUDY OF DEPTH OF ANTERIOR SKULL BASE IN DAKSHINA KANNADA POPULATION. Int J Anat Res 2016;4(3):2738-2742. DOI: 10.16965/ijar.2016.320




Volume 1 (2013)

Volume 2 (2014)

Volume 3 (2015)

Volume 4 (2016)

Submit Manuscript