Final answer:
The radiological features of osteosarcoma, a type of bone cancer, include a sunburst pattern and Codman's triangle, which can be observed in radiographic images. The question also touches on identifying bones without an epiphyseal plate in a child's hand radiograph, which indicates bone development stage.
Step-by-step explanation:
The subject of the question revolves around the radiological features of osteosarcoma, which are typically observed in radiographic images as a sunburst pattern and Codman's triangle near the growth plate or epiphyseal plate. The sunburst pattern refers to the aggressive growth of the tumor causing new bone and soft tissue to form in a radiating pattern. Codman's triangle is an area of new subperiosteal bone that forms as a tumor lifts the periosteum away from the bone. Both of these features are indicative of osteosarcoma, a type of bone cancer that usually occurs near the metaphyses of long bones in children and young adults.
Regarding the second part of the question about the study of radiographs, such images can show the epiphyseal plates of growing bones as dark gaps. These epiphyseal plates are regions where new bone cells are produced, contributing to the longitudinal growth of the bone. Not all the bones in the radiograph of a child's hand will show an epiphyseal plate, which is typically absent in bones that are fully developed or in certain bones according to the child's age and developmental stage.