Musculoskeletal ImagingSymphysis
a type of
cartilaginous joint in which adjacent bone surfaces are connected by a cartilaginous disc composed of fibrocartilaginous or fibrous connective tissue, although a thin layer of hyaline
cartilage usually persists. The
symphysis pubis,
manubriosternal joint and
intervertebral disc are typical examples. Symphyses allow a small amount of motion, which occurs through deformation of the intervening connective tissue.
In some instances the symphysis may have a small cleftlike central cavity demonstrable radiographically because of the presence of gas, termed the vacuum phenomenon.
A diastasis or abnormal separation of a joint that is normally only slightly movable may occur under various conditions such as trauma or pregnancy. Subluxation or dislocation may also occur, as in the manubriosternal joint in automobile accidents in which the chest strikes the steering wheel or in the symphysis pubis, in which a single break in the pelvic ring may occur but is commonly combined with a second injury, such as a fracture of the ilium or sacrum or a diastasis of the sacroiliac joint.
Trauma to the discovertebral junction can lead to violation of the cartilaginous endplate and subchondral bone plate of the vertebral body, allowing intraosseous displacement of discal material (cartilaginous or Schmorls node. On radiographs one or more radiolucent areas with bone sclerosis in the vertebral body as well as intervertebral disc space loss may be present. CT scanning and MR imaging may provide additional diagnostic information.
DR