The Anterior Third of the Sagittal Sinus: Anatomical Study and Neurosurgical Importance

Introduction: The superior sagittal sinus (SSS) anterior third ligation can cause severe mental disorders, personality changes, recent memory loss, akinetic mutism, cerebral edema, and frontal venous infarction leading to death. Starting with Cushing's Meningiomas text (1938), many reports of the ligation of this SSS portion have been described as well tolerated by the patient. The objective of this study is to quantitatively determine the anterior third of the SSS and its anatomical pattern.

Methods: Eight cadaveric heads injected on the vascular tree were submitted to bilateral craniotomy. The SSS was measured and its length split in three equal segments. The distance between the bregma and the anterior third of the SSS was determined. The SSS anterior third area of drainage was observed and its venous tributaries were counted and classified according to its diameter using a caliper.

Results: The SSS anterior third average length is 271.8 mm (± 16.3 mm) and its anterior third measures 90.5 mm (± 5.4 mm). The anterior third is anterior to the bregma and is an average of 19 mm (± 3.7 mm) from it. There are an average of 3.7 veins draining to the right side and 4 draining to the left side of the anterior third of the SSS.

Conclusion: Olivercrona classified the SSS into three divisions in 1932 and Cushing advocated the ligation of the anterior third in 1938. By our study the anterior third of the SSS is defined as the segment between the crista galli and 19 mm anterior to the bregma.