Hematoma or a bruise is a discolored area of the skin. Hematoma is caused when the small blood vessels are broken and their contents are leaked into the soft tissue under the skin. Hematoma is often caused by sport injuries, falls, blows by other objects or person or car accidents. The main symptoms of this condition are swelling, pain and discoloration of the skin. Hematoma begins as a pinkish red color which is tender to touch. The muscle that has been affected becomes difficult to use. For instance, walking or running with a bruised thigh becomes difficult. Hematoma finally changes to bluish color, then greenish-yellow and then returns to its original color once it ha s healed.