Critical limb ischemia is a medical condition that occurs when arteries supplying blood to the limbs become narrowed or blocked. There are several synonyms for the term, such as advanced peripheral arterial disease, chronic arterial insufficiency, arterial occlusive disease, and limb-threatening ischemia. The condition often causes severe pain in the affected limb, especially during physical activity. Other symptoms may include sores or ulcers that don't heal, skin discoloration, and a reduced ability to move the affected limb. Treatment for critical limb ischemia includes lifestyle changes, medications, and in some cases, surgery. Without treatment, the condition can lead to amputation of the affected limb, making early detection and treatment essential.