• Muscular strain
• Baker’s cyst (rupture or obstruction of popliteal vein)
• Achilles tendon rupture
• Cellulitis
• Superficial thrombophlebitis
• Lymphatic obstruction, eg, obstruction by pelvic tumor
• Reflex sympathetic dystrophy
• Tumor or fibrosis obstructing iliac vein
• May-Thurner syndrome (left iliac vein compressed by right common iliac artery)

• Calf pain
• Hypercoagulable state
• Unilateral edema
• Pulmonary thromboembolism

Risk factors

• Bed rest or immobility
• Hypercoagulable state, eg, malignancy, nephrotic syndrome, inherited defect
• Advanced age
• Oral contraceptive use
• Systemic lupus erythematosus or antiphospholipid antibody syndrome