Chapter 51: alterations in musculoskeletal function: trauma, infection, and disease. Bones are subject to different types of fracture, depending on the type of tension stress imposed. Fractures can be classified according to the orientation of the break as transverse, longitudinal, oblique, or spiral. A comminuted fracture consists of more than one fracture line and more than two bone fragments. Fractures are classified as open or compound when the skin is penetrated and as closed or simple when the skin is not broken. Healing of fractured cancellous bone occurs more quickly than healing of cortical bone. Trauma causes hematoma formation, followed by callus formation. The callus is initially soft and cartilaginous; then it progressively ossifies to become firm and stable. The fracture is clinically stable when no movement at the break is detectable. Radiographically apparent union occurs when the callus has been completely replaced by mature bone. Healing of fractured bone is contingent on stabilization and time.