Venous embolism means a clot that forms in a vein, then breaks off and floats to the lung (pulmonary embolism) or blocks a vein elsewhere. It usually starts in the legs, so leg clues are the first red flag.

Sudden calf pain is the headline. It feels like a deep cramp or “charley horse” that doesn’t ease with stretching.

One-sided swelling shows up fast. The ankle or lower leg puffs, and socks leave a tight groove on that leg only.

Warmth and redness appear. Skin over the vein feels hot and looks pink or purplish, like a localized sunburn.

Heavy, tight feeling follows. The leg feels wooden, full, and tired even after short walks.

Superficial veins may pop out. Blue cords bulge as deeper veins are blocked and blood reroutes.

Late alarms include sudden chest pain, shortness of breath, or coughing up blood—clues the clot has traveled to the lung.