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|Contusion (bruise), a simple form of hematoma.|
A hematoma, also spelled haematoma, is a localized bleeding outside of blood vessels, due to either disease or trauma including injury or surgery and may involve blood continuing to seep from broken capillaries. A hematoma is benign and is initially in liquid form spread among the tissues including in sacs between tissues where it may coagulate and solidify before blood is reabsorbed into blood vessels. An ecchymosis is a hematoma of the skin larger than 10mm.
They may occur among/within many areas such as skin and other organs, connective tissues, bone, joints and muscle.
A collection of blood (or even a hemorrhage) may be aggravated by anticoagulant medication (blood thinner). Blood seepage and collection of blood may occur if heparin is given via an intramuscular route; to avoid this, heparin must be given intravenously or subcutaneously.
Signs and symptoms
Some hematomas are visible under the surface of the skin (commonly called bruises) or possibly felt as masses/lumps. Lumps may be caused by the limitation of the blood to a sac, subcutaneous or intramuscular tissue space isolated by fascial planes. This is a key anatomical feature that helps prevent injuries from causing massive blood loss. In most cases the hematoma such as a sac of blood eventually dissolves; however, in some cases they may continue to grow such as due to blood seepage or show no change. If the sac of blood does not disappear, then it may need to be surgically cleaned out/repaired.
The slow process of reabsorption of hematomas can allow the broken down blood cells and hemoglobin pigment to 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.
In most cases, movement and exercise of the affected muscle is the best way to introduce the collection back into the blood stream.
A misdiagnosis of a hematoma in the vertebra can sometimes occur; this is correctly called a hemangioma (buildup of cells) or a benign tumor.
- Subdermal hematoma (under the skin)
- Intramuscular hematoma (inside muscle tissue)
- Subgaleal hematoma – between the galea aponeurosis and periosteum
- Cephalohematoma – between the periosteum and skull. Commonly caused by vacuum delivery and vertex delivery.
- 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
- Breast hematoma (breast)
- Perichondral hematoma (ear)
- Perianal hematoma (anus)
- Subungual hematoma (nail)
- Rectus sheath hematoma
- Petechiae – small pinpoint hematomas less than 3 mm in diameter
- Purpura (purple) – a bruise about 3 – 5 mm in diameter, generally round in shape
- Ecchymosis – subcutaneous extravasation of blood in a thin layer under the skin, i.e. bruising or "black and blue," over 1 cm in diameter
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- Robbins basic pathology. Kumar, Vinay, 1944-, Abbas, Abul K.,, Aster, Jon C.,, Perkins, James A. (10th ed.). Philadelphia, Pennsylvania. 2017-03-28. p. 101. ISBN 9780323353175. OCLC 960844656.CS1 maint: others (link)
- "hematoma". Online Etymology Dictionary.
- Media related to Hematomas at Wikimedia Commons