Fig 3. (Case I) Distribution of wall shear stresses (WSS) in the internal carotid artery at the level of the aneurysm in case I. A and C represent the conditions before aneurysmal development (based on artificial aneurysm removal as described above) at end diastole (A) and peak systole (C), whereas B and D show the conditions after aneurysm development, respectively. The WSS vectors (small black arrows), clipped to display the WSS behavior mainly in the vicinity of the aneurysm, are superimposed on contour plots of WSS magnitude. Blue corresponds to spatial minimum and red corresponds to spatial maximum. Range of WSS magnitudes: A and B, 0–16 Pa; C and D, 0–100 Pa. Range of WSS vectors: A and B, 0–5 Pa; C and D, 0–30 Pa. Note that the WSS in the area of subsequent aneurysm development (A and C) is relatively low at both end diastole and peak systole. The random orientation of these vectors indicates a stagnation zone in this area.