RESUMEN
Background: Cortical folding is a hallmark of many but not all mammalian brains. The degree of folding graduallyincreases with the size of brains in mammals but at different range between the families.Gyrification is a processwhich varies widely in mammals in early foetal and prenatal life.Materials: This study was conducted on 100 dead foetuses in anatomy department, brought from the departmentof Obstetrics and gynaecology of MNR Medical College and Hospital.Results: The brain surface is smooth up to 12 weeks,Cingulate sulcus appeared by 16-18weeks.Growth of adjoininglobes of brain make surface more convoluted with well-defined sulci and gyral pattern between 30-32 weeks.Conclusion: Cortical folding is due to consequence of restricted space and rapid growth of brain with in thecranial cavity. There is no differences between male and female brains of same gestational age, with no obviousasymmetrical development of gyri on different lobes of brain