Medical devices for navigation through anatomy, including guidewires (100), which may have a core wire (150), a slotted tubular member (130), or both. Embodiments may have coils (200; 345; 600; 114 1; 1143; 1243; 2238; 2266; 2441), including non-circular cross-section edge-wound marker coils (200), extended coil tips (300), and soldered or glued mesial joint coils (1141; 1143; 1243). Core wires (150) may have a step (1551; 2151; 2152), ridge (1351), or taper (1253) at the joint (140) to the tubular member (130), and may have a flattened section (1057) at the distal tip (257). Radiopaque material (801; 802) may be located inside the tubular member (130), and the distal tip (138) may be heat treated to make it shapeable. Additional tubular members (730; 2062; 2130; 2162; 2439) or coils (200; 345; 600; 1141; 1143; 1243; 2238; 2266; 2441) may be used concentrically or in line and may enhance flexibility, provide radiopacity, reduce friction, or reduce material or manufacturing cost. Tubular members (130; 730; 2062; 2130; 2162; 2439) may be chamfered (231) or tapered continuously or incrementally. Slots (135) maybe arranged in-groups (235; 1635), such as groups of three (1635), and may be equal in depth or unequal in depth to provide a steerable or compressible tip.