Cartilaginous (Schmorl's) nodes are related to prolapses of intervertebral disk material into the vertebral body. These nodes can be produced by any process which weakens either the cartilaginous plate covering the superior and inferior surfaces of the vertebral body or the subchondral trabeculae of the vertebra. Such processes include juvenile kyphosis, trauma, metabolic and neoplastic disorders, and degenerative disk disease. Radiographic abnormalities include indentations of vertebral outline and radiolucencies within the vertebral body with varying degrees of sclerosis. These can be readily differentiated from other vertebral alterations such as "butterfly", "fish", and "H" vertebrae.