Most thumb sprains involve the ulnar collateral ligament, which is located on the inside of the knuckle joint. A tear to this ligament can make your thumb feel.
A sprain can occur when a ligament in the thumb is injured or torn. Ligaments connect two bones, forming a joint. A sprain can be very painful.
A thumb sprain is much less serious than a broken thumb because the your thumb near your palm at the metacarpophalangeal joint (MCPJ).