Interhemispheric Variation of Sylvian Fissure: A Cadaveric Brain Study.

ABSTRACT

Introduction: Language areas of brain show a beautiful anatomico-functional correlation. It has been often assumed that the interhemispheric asymmetry of Sylvian fissure and perisylvian cortex is the basis of hemispheric dominance for language.The lateral sulcus is one of the earliest-developing sulci of the human brain. Materials And Methods: 60 formalin fixed cadaveric brains irrespective of sexes were studied in the department of Anatomy. The total length of sylvian fissure on the superolateral surface till the posterior sylvian point was noted bilaterally. Among the other measurements taken were the lengths of anterior ascending, anterior horizontal and posterior limb of lateral sulcus till posterior sylvian point on the right and left cerebral hemispheres. Observation and Results: The mean of the total length of the lateral sulcus on the left side is 8.48 which is larger than the right side which is 8.39.The mean of the anterior horizontal rami on right side (1.97) is greater than left side (1.96). On the other hand the mean value of left anterior ascending ramus 2.41 is greater than the mean value of right anterior ascending ramus 2.37. The mean value of posterior limb of sylvian sulcus is also greater on the left side i.e. 6.43 than on the right side i.e.6.23.All measurements are in cms. Conclusion: The Sylvian fissure in this study is longer on the left side than the right which has been proved in previous studies.To correlate this structural asymmetry with the functional localization of speech and language calls for further studies.