Two cases of persistent falcine sinus.

C orreondence To The Editor We read with interest the paper by Cai et al. These authors described two cases of persistent falcine sinus. We would like to add to the authors' discussion by mentioning a recent study of ours. We found that in 25 adult cadavers an extensive network of small tributaries within the falx cerebri could always be found, especially within its posterior one third (Fig.). In this posterior segment, these structures were usually more pronounced in the inferior two thirds. The portion of the falx cerebri not containing signifi cant falcine venous sinus was termed a "safe area" for surgical consideration. These vascular channels ranged in size from 0.5 mm to 1.1 cm (mean 0.6 mm). 100% of these vessels communicated with the inferior sagittal sinus. Typing was performed based on communication of the falcine venous sinus with the superior sagittal sinus. Type I falcine sinuses had no communication with the superior sagittal sinus, Type II falcine sinuses had limited communication with the superior sagittal sinus, and Type III falcine sinuses had signifi cant communication with the superior sagittal sinus. Seventeen of 27 (63%) specimens had communication with the superior sagittal sinus (Types II and III). Further subdivision revealed 10 Type I, 7 Type II, and 10 Type III falcine venous plexuses. As the majority of specimens in our study were found to have a plexiform venous morphology within the falx cerebri, we propose that these channels be referred to as the falcine venous plexus and not sinus. R. Shane Tubbs Marios Loukas Mohammadali Shoja Pediatric Neurosurgery Children's Hospital Birmingham, AL, 35233 USA Email: [email protected]