as for galen you have already learned what he said about it. he does not mean by its being bounded by this wall from below that it is parallel to the cortical suture as we have seen a group of people who imagine that but rather that it is like two sides of a triangle surrounding an angle whose hypotenuse is the cortical suture because the shape of this wall as you have learned is the shape of a triangle.
وأما جالينوس فقد عرفت قوله فيه. وليس يريد بكونه يحد هذا الجدار من أسفل أن يكون موازيا للدرز القشري كما رأينا جماعة يتوهمون ذلك، بل إنه يكون كضلعي مثلث يحيطان بزاوية وترها الدرز القشري، لأن هذا الجدار شكله كما علمت شكل مثلث.