Radiology Definitions Flashcards
What is a dislocation in joint anatomy?
A dislocation occurs when the body components of a joint are no longer in contact with each other, leading to a complete disruption of the joint.
How does subluxation differ from dislocation?
In subluxation, the bony elements of the joint are still partially in contact with each other, and there is only partial disruption of the joint, unlike a dislocation where there is complete separation.
What is a fracture?
A fracture is a disruption in the cortex of the bone, which can vary in severity.
What distinguishes a complete fracture from an incomplete fracture?
A complete fracture (typically in adults) involves both cortices of the bone, while an incomplete fracture (more common in children) only involves one cortex of the bone.
What is true for a complete fracture in a mature skeleton?
Even if the fracture is not visible on imaging, a complete fracture in a mature skeleton goes through both cortices of the bone.
What is a greenstick fracture?
A greenstick fracture is an incomplete fracture that goes through only one cortex of the bone, commonly seen in children.
What is a torus fracture (buckle fracture)?
A torus (or buckle) fracture occurs when there is buckling of the cortex, typically seen in children due to their softer bones.
What is a transverse fracture?
A transverse fracture is perpendicular to the long axis of the bone and is caused by a force applied perpendicular to the bone.
How does a diagonal (oblique) fracture occur?
A diagonal (oblique) fracture occurs at an oblique angle to the long axis of the bone, typically caused by a force in the same direction as the bone’s long axis or the direction of the fracture.
What causes a longitudinal fracture?
A longitudinal fracture is caused by cranio-caudal forces, such as a fall from height, which results in the bone splitting along its length.
What is a spiral fracture?
A spiral fracture is caused by a twisting motion, such as during a torque injury, for example, when a foot is planted in a hole while running.
What is an impacted fracture?
An impacted fracture occurs when the broken sections of the bone are jammed together due to a compressive force.
What is the difference between a simple and a comminuted fracture?
A simple fracture involves two fragments, whereas a comminuted fracture involves more than two fragments.
What is a comminuted fracture?
A comminuted fracture involves more than two pieces, typically caused by high-speed or high-impact injuries. Larger fragments may be described as “butterfly” fragments.
What causes a stress fracture?
A stress fracture is caused by repetitive strain and results in microfractures in the bone, often seen in athletes or individuals involved in repetitive activity.
What is an avulsion fracture?
An avulsion fracture occurs when a tendon or ligament pulls off a piece of bone at the point of attachment.
What is meant by displacement in a fracture?
Displacement refers to the amount of offset of the distal fracture fragment relative to the proximal fragment.
What is shortening in a fracture?
Shortening, or overlapping, occurs when the ends of the fracture fragments overlap, causing the bone to shorten. The degree of shortening is described by the number of centimeters of overlap, as well as the displacement in terms of the bone’s width.
What is angulation in a fracture?
Angulation refers to the angle that the distal fragment makes away from the normal alignment in relation to the proximal fragment.
For example, in a wrist fracture, this could involve radial or ulnar angulation.
What does rotation in a fracture usually involve?
Rotation typically involves long bones, such as the humerus or femur. It refers to a twisting or turning of the bone fragments that distorts the normal alignment.
In this case, the knee joint is shown in an AP (anterior-posterior) view, and the ankle in lateral view.
What is an open intra-articular comminuted fracture?
An open intra-articular comminuted fracture involves the fracture of the bone within a joint (such as the proximal radius and ulna), with multiple bone fragments. This type of fracture can also involve air in the soft tissues, indicating that the fracture site has been exposed to the outside environment.
