Wound and healing 2, Injuries

Common types of wound
Contusion
A contusion is more commonly called a bruise. It is usually caused by a blunt blow, the overlying skin is unbroken, but tissues and blood vessels below are damaged. The discolouration is caused by bleeding from small vessels into the tissues. Red blood cells trapped in the tissue spaces become deoxygenated anddark coloured. Bruising can also develop after deeper tissues, such as bones are damaged, and may only become apparent after a period of time as blood tracks towards the body surface.
If blood collects in a discrete pool within the tissues this is described as a haematoma. As the blood in a haematoma is well consolidated it may cause pressure effects on surrounding tissues, these may include pain and nerve compression. There is a risk a haematoma may become infected and some need to be surgically evacuated.
Abrasion
An abrasion is a scrape or graze. Typically, there is a superficial surface wound involving the epidermis and part of the dermis. As dermal nociceptors are exposed in the damaged dermis, these wounds are often very painful. Some abrasions can however, be deeper wounds involving tissues below the level of the skin. Abrasions are most commonly caused by friction injuries, falling off bikes is a common cause. These wounds need to be well cleaned to remove dirt and grit which may be sticking to the wound surface.