- Less common than arterial ischemia
- Hypercoaguable state→ factor 5 leiden defic, protein S/C/AT 3 defic, prothombin mutation, antiphoslipid antibody synd, parox noct hemoglobinuria
- Hx idipathic dvt/pe, malignancy, other inflam process
- Few exam findings/pain out of proportion to findings
- Severe illness if progresses to necrosis