Sprains affect ligaments, the tough bands that hold bones together at a joint. They are common in the ankle, knee, and wrist, often after a twist or sudden wrench. Typical signs are pain, swelling, bruising, and joint instability.
Strains affect muscles or the tendons that attach muscle to bone. They are common in the lower back, hamstring, and calf, usually from overstretching or overuse. Symptoms include pain, muscle spasm, swelling, and reduced movement.
Mild sprains and strains are usually managed at home with protection, rest, ice, compression, and elevation in the first couple of days, followed by gradual return to movement. Seek medical assessment if you cannot bear weight, the joint looks deformed, there is severe swelling or numbness, or there is no improvement after a few days, as a fracture or more serious tear may need treatment.