Lines of Zahn

[2][3] Platelets mixed with fibrin form lighter layers.

[2] Red blood cells form darker layers.

[2] Sometimes, the term "lines of Zahn" only refers to the lighter layers.

[1] Their presence implies thrombosis at a site of rapid blood flow that happened before death.

[5] In veins or smaller arteries, where flow is not as constant, they occur less frequently.