A subungual hematoma is the presence of blood under the nail.

One of our outdoor steps at home needed to be replaced. In these difficult economic times, I thought, "No need to call a carpenter, this is a chore that I can easily do."


I made the necessary measurements, bought some lumber, got out my handy hammer and a box of nails, and was ready to replace the missing step.


On my first attempt, my trusty hammer made a direct hit on the nail. On my second attempt, I again made a direct hit, but this time it was the wrong nail - I hit the nail located on my fourth finger.


Yes, it did hurt and throb and, yes, the nail quickly became a light bluish color, slowly changing to ink-blue.


The diagnosis was a subungual hematoma, the presence of blood under the nail. The pain is due to the pressure caused by the accumulation of blood in this closed, confined space.


If the trauma is severe enough, the bones in the area may be fractured, also resulting in discomfort.


Usually, no treatment is needed If there is only a small amount of blood under the nail and no pain is present. However, if most of the nail is involved and there is a great deal of pain, the pain can be relieved by making a small opening in the nail. This is called nail trephination, and it relieves the pressure as the blood escapes through the opening.


There are various ways to make an opening in the nail, such as using a large needle or even the end of a paper clip that has been heated. I found that using a hot paper clip on the nail of a patient is easier for me to do than doing it on myself. So I decided to live with the discomfort and if it got too bad I would have someone else wield the paper clip.


Frequently, the nail falls off and it takes two months or longer for it to grow back.


Some complications of this injury are infections, injury to the nail bed, deformity of the new nail, and injury to the ligament involving the tip of the finger.


The day after my nail trauma, I met a friend, a carpenter, who noted my blue nail. Without asking how it happened he said, "Some people should never be allowed to use a hammer."


I learned that lesson the hard way.


Massachusetts-based Dr. Murray Feingold is the physician in chief of the National Birth Defects Center, medical editor of WBZ-TV and WBZ radio, and president of the Genesis Fund. The Genesis Fund is a nonprofit organization that funds the care of children born with birth defects, mental retardation and genetic diseases.