, or haematoma
, is a collection of blood
outside the blood vessels, generally the result of hemorrhage
, or more specifically, internal bleeding
It is not to be confused with hemangioma which is an abnormal build up of blood vessels in the skin or internal organs.
Hematomas exist as bruises
), but can also develop in organs
. Some hematomas form into welt-like formations that are hard to the touch. Such a formation is a sac of blood that the body creates to keep internal bleeding to a minimum. In most cases the sac of blood eventually dissolves, however, in some cases they may continue to grow or show no change. If the sac of blood does not disappear, then it may need to be surgically removed.
Hematomas can gradually migrate, as the effused cells and pigment move in the connective tissue. For example, a patient who injures the base of his thumb might cause a hematoma, which will slowly move all through the finger within a week. Gravity is the main determinant of this process.
Hematomas on articulations can reduce mobility of a member and present roughly the same symptoms as a fracture.
Degrees of hematoma
- Hematoma - bruise
- Petechiae - small pinpoint hematomas less than 3 mm in diameter
- Purpura - (purple) a bruise about 1 cm in diameter, generally round in shape
- Ecchymoses or eccymosis - hematoma greater than 3 mm
A common sport-related haematoma of the muscle is known as a 'cork', most commonly a "cork thigh" (quadriceps
), but also calf and arm, in which the muscle is compressed against the underlying bone. Rupture of the muscle causes haematoma, resulting in swelling.