An avulsion is a cut in which a portion of the skin or other soft tissue is partly or completely torn away, exposing fat or muscle.
In terms of medicine, an avulsion is an injury in which a body structure is torn off by either trauma or surgery. It takes place when when a tendon or ligament that is joined to the bone pulls a piece of the fractured bone off. The sort of fractures are caused by trauma.
The symptoms of an avulsion fracture may be:
intense and sudden pain where the trauma occurred
swelling
bruising
trouble moving the bone or joint
pain in an attempt to move