Computational macroscopical patterning of the medullary striae of fourth ventricle

The aim of this study was to pattern macroscopically, by use of computational tools, the number and distribution of the medullary striae (MS) of fourth ventricle. After removing 71 fresh human brain stems, each respective rhomboid fossa was photographed. The MS were carefully identified to be shaped and fulfilled by means of a digital pen, using the Adobe Photoshop CS3® program. For absolute and relative analyses of number and distribution, it was considered the maximum and minimum numbers of striae; striae that reached the ipsilateral lateral recess; presence of horizontal or oblique striae, with or without parallelism; and striae located at pontine or bulbar part of the rhomboid fossa. At least two MS per side were macroscopically detectable in 90.6% of cases; they were bilaterally absent in 5.3% of pieces; and at least one medullary stria was present in both sides of the rhomboid fossa in 92% of cases. As on the right side (36% of cases) as on the left (26.6%), two MS were frequently more present. In 60% of cases, striae reached ipsilateral lateral recess on the left, and in 40% of cases on the right. It was detected horizontal, (non-parallel) oblique and parallel striae in 50.7, 86.7 and 26.7% of cases, respectively. Medial medullary striae were observed in the bulbar part of rhomboid fossa in 80% of pieces, and in 36% of cases in the pontine part. The MS of fourth ventricle show high morphological variability degree in relation to number and distribution.