Fractures are described and classified by the extent, direction, position, and number of fracture lines and the integrity of the overlying skin.A fracture that results in discontinuity between two or more fragments is complete; an incomplete fracture causes only partial discontinuity, with a portion of the cortex remaining intact.In closed fractures, the overlying skin is intact; if the overlying skin is disrupted, the fracture is open.Although this is a clinical distinction, the radiographic demonstration of bone clearly protruding through the skin and the presence of air in soft tissues about the fracture site on immediate postinjury radiographs are findings that are highly suggestive of an open fracture.
The direction of a fracture is determined by its relation to the long axis of long and short bones (e.g., the talus or carpal navicular).A transverse fracture runs at a right angle to the long axis of a bone and is most commonly the result of a direct blow or a fracture within pathologic bone.An oblique fracture runs a course of approximately 45° to the long axis of the bone and is the result of angulation or of angulation and compression forces.A spiral fracture encircles the shaft, is generally longer than an oblique fracture, and is caused by torsional forces.Avulsion fractures are generally small fragments avulsed from bony prominences; they are usually the result of indirectly applied tension forces within attached ligaments and tendons rather than direct blows.
A comminuted fracture is composed of more than two fragments.A butterfly fragment is an elongated triangular fragment of cortical bone generally detached from two other larger fragments of a bone; a segmental fracture consists of a segment of the shaft isolated by a proximal and a distal line of fracture.
A compression fracture results from a compression force that causes compaction of bone trabeculae and results in decreased length or width of a portion of the bone.Compression fractures most commonly occur in the vertebral body as a result of flexion of the spine; they may also be seen as impacted fractures of the humeral or femoral heads.A depressed fracture occurs in the skull or tibial plateau.In the skull, a small object with great force can prodce a comminuted fracture with portions of the fracture fragment driven inward.In the knee, the relatively hard lateral femoral condyle may impact on the relatively soft lateral tibial plateau with sufficient force to push the cortical surface of the tibia into the underlying cancellous bone.
A stress, or fatigue, fracture is the response of bone to repeated stresses, no one of which is sufficient to cause a fracture.The earliest pathologic process in a stress fracture is osteoclastic resorption, followed by the development of periosteal callus in an attempt to repair and strengthen the bone.A pathologic fracture occurs in bone at an area of weakness caused by such processes as tumor, infection, or metabolic bone disease.
A greenstick fracture is an incomplete fracture with the opposite cortex intact.A torus (buckle) fracture is one in which one cortex is intact with buckling or compaction of the opposite cortex.A bowing fracture is a plastic deformation due to a stress that is too great to permit a complete recovery of normal shape but is less than the stress required to produce a fracture.
A fracture is undisplaced when a plane of cleavage exist in the bone without angulation or displacement.Displacement refers to separation of bone fragments; the direction of displacement is described by the relation of the distal fragment with respect to the proximal fragment and is usually measured in terms of the thickness of the shaft.Angulation indicates an angular deformity between the axes of the major fragments and is also described by the position of the distal fragment with respect to the proximal one.Dislocation refers to displacement of a bone in relation to the apposing bone at a joint, which results in a complete loss of continuity of the joint surfaces, the displacement is called a subluxation.A diastasis is a displacement of a bone in relation to the apposing bone in a slightly movable or synarthrodial joint (e.g., tibiofibular joint at the ankle; symphysis pubis).comminuted fracture · fracture · fractures ·