The plastic loading and unloading cycle near the crack tip leads to the dissipation of energy as heat. As the applied load increases, the plastic zone increases in size until the crack grows and the elastically strained material behind the crack tip unloads. A Colles fracture occurs when the broken end of the radius tilts upward. This fracture was first described in 1814 by an Irish surgeon and anatomist, Abraham Colles hence the name Colles fracture. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the materials resistance to fracture. One of the most common distal radius fractures is a Colles fracture, in which the broken fragment of the radius tilts upward. In ductile materials (and even in materials that appear to be brittle ), a plastic zone develops at the tip of the crack. Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. Naval Research Laboratory (NRL) during World War II realized that plasticity must play a significant role in the fracture of ductile materials. When the plastic zone at the tip of the crack is small relative to the crack length the stress state at the crack tip is the result of elastic forces within the material and is termed linear elastic fracture mechanics ( LEFM) and can be characterised using the stress intensity factor K still holds, the surface energy ( γ) predicted by Griffith's theory is usually unrealistically high. A number of different parameters have been developed. The most common type of compression fracture is the wedge fractures. When enormous amounts of pressure are applied to a spinal vertebrae, it becomes compressed, resulting in its collapse. Fracture mechanics is used to characterise the loads on a crack, typically using a single parameter to describe the complete loading state at the crack tip. Compression fractures are classified into three types: wedge fractures, crush fractures, and burst fractures. Theoretically, the stress ahead of a sharp crack tip becomes infinite and cannot be used to describe the state around a crack. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture. Another possible complication is compartment syndrome, a painful condition resulting from the expansion of enclosed tissue and that may occur when a body part is immobilized in a cast.Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. Open fractures may lead to bone infections, which delay the healing process. Recovery is complete when there is no bone motion at the fracture site, and x rays indicate complete healing. A non-union fracture may result when a fracture does not heal, such as in the case of an elderly person or an individual with medical complications. Healing time varies from person to person with the elderly generally needing more time to heal completely. Realignment has been shown to be much more difficult after six hours. If determined necessary by a physician, the fractured site should be manipulated, realigned, and immobilized as soon as possible. Fractures can normally be cured with proper first aid and appropriate aftercare. Causes and symptomsįractures involving joint surfaces almost always lead to some degree of arthritis of the joint. An example of segmental alignment is when the arm bone fractures in two separate places, with displacement of the middle section of bone. Segmental fragmented positioning occurs if fractures in two adjacent areas occur, leaving an isolated central segment. An avulsed fragment occurs when bone fragments are pulled from their normal position by forceful muscle contractions or resistance from ligaments. A displaced bony fragment occurs from disruption of normal bone alignment with deformity of these segments separate from one another. Angulated fragments result in pieces of bone being at angles to each other. Overriding is a term used to describe bony fragments that overlap and shorten the total length of a bone. Bone can fracture crosswise, lengthwise, in several places. It can range from a thin crack to a complete break. An impacted fracture is characterized as a bone fragment forced into or onto another fragment resulting from a compressive force. Treatment Outlook Prevention What is a fracture A fracture is a broken bone. Fragments of bone that maintain their normal alignment following a fracture are described as being non-displaced. Comminuted fractures have two or more fragments broken into small pieces, in addition to the upper and lower halves of a fractured bone.
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