RBC fragment formation in mesenteric venules visualized by brightfield intravital microscopy. Elapsed times from the initial frames (panels a) are as indicated (seconds). For the example shown in (A), 2 RBCs (Ab, arrows) become associated with the endothelial surface; a firm adhesion point becomes visible within 1 of the RBCs (Ac, black arrow), with this RBC becoming elongated in the direction of flow (Ac, white arrow); the elongated RBC appears to be anchored to the firm adhesion point (Ad, white arrow); the elongated RBC breaks free from the firm adhesion point (Ae, white arrow); and the RBC fragment is left associated with the endothelial surface (Af, black arrow). (B-C) The black arrows indicate the firm adhesion point, and the white arrows indicate the adherent RBC fragment.