Morphometric Analysis and Variation of Pterion, Asterion and Lambda in Dry Human Skulls and Its Sexual Dimorphism

Introduction: Pterion is a H- shaped sutural junction of the frontal, parietal, squamous part of the temporal and greater wing of sphenoid bone. Asterion is a sutural junction of lambdoid, parietomastoid and occipitomastoid sutures. Lambda is the junction where lambdoid sutures and sagittal sutures meet. These sutures play an important role in infants' brain development. Flexibility of these allows the bones to overlap and hence it can pass through the brain canal easily without any damage to the brain.

Aim: To analyse pterion asterion and lambda of dry human skulls morphologically and morphometrically and determine its sexual dimorphism.

Materials and Methods: 40 dry human skulls were collected from the department of Anatomy of Saveetha dental college and hospitals. By excluding abnormal and damaged skulls, 20 skulls were studied. Out of 20 skulls, 11 were male skulls and 9 were female skulls. On investigation, Pterion was classified into four types: Sphenoparietal, stellate, Epipteric and Frontotemporal. Asterion was classified into types: Type-1 and Type-2 based on the presence and absence of wormian bones respectively. Lamda was classified into two types: Normal and Abnormal. Statistical analysis was done by SPSS software. Paired Sample T test was used to analyse the data.

Results: Percentage of occurrence of different types of pterion in males and females: Sphenoparietal (59.09 % of males and 59.09 % of females), Stellate (27.7% of males and 22.2% of females), Epipteric (99% of males and 16.6% of females) and Frontotemporal (45.5% of males and 5.5% of females). Different types of Asterion: Type-1 (13.63% of males and 16.66 % of females and Type -2 (86.63% of males and 83.33% of females). Different types of Lambda: Normal (90.9% of males and 94.4% of females), Abnormal (9% of males and 5.55% of females).

Conclusion: In the present study, there was no correlation between the male and female skulls in the presence of Pterion, Asterion and Lambda. Therefore these cannot be used as reliable parameters for determining sexual dimorphism.