Hematoma

A hematoma, or haematoma, is a collection of blood outside the blood vessels, generally the result of hemorrhage, or more specifically, internal bleeding. It is commonly called a bruise.

It is not to be confused with hemangioma which is an abnormal build up of blood vessels in the skin or internal organs.

Presentation

Hematoma—from Greek αίμα, haima, blood + τωμα, t-oma—indicating an abnormality.

Hematomas exist as bruises (ecchymosis), but can also develop in organs.There are two kinds, an intermuscular and intramuscular hematoma. 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.

Types

Head/brain:

• Subgaleal hematoma – between the galea aponeurosis and periosteum
• Cephalhematoma – between the periosteum and skull
• Epidural hematoma – between the skull and dura mater
• Subdural hematoma – between the dura mater and arachnoid mater
• Subarachnoid hematoma – between the arachnoid mater and pia mater (the subarachnoid space)
• Othematoma – between the skin and the layers of cartilage of the ear

Perichondral hematoma (ear)
Perianal hematoma (anus)
Subungual hematoma (nail)

Degrees of hematoma

Petechiae – small pinpoint hematomas less than 3 mm in diameter
Purpura (purple) – a bruise about 1 cm in diameter, generally round in shape
Ecchymosis – hematoma greater than 3 cm

Sport injuries

A common sport-related hematoma 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 hematoma, resulting in swelling.