What is defined as a fracture with three or more fragments with proximal and distal fragments not touching?

The definition given in the question describes a comminuted fracture. This type of fracture occurs when a bone is broken into three or more pieces, with the proximal and distal fragments separated and not in contact with one another. This classification reflects the degree of fragmentation and the resulting instability of the bone structure, which often requires surgical intervention to properly align and stabilize the fragments for healing.

A simple fracture involves a break in the bone that does not result in any separation of the bone fragments; hence, it does not fit the description of having multiple fragments. A complex fracture typically refers to a fracture that has associated soft tissue injuries but does not specifically denote the number of fragments involved as the defining characteristic. A greenstick fracture is a type specific to children where the bone bends and breaks partially, resembling a green twig, and also does not meet the criteria of having multiple fragments. This context clarifies that a comminuted fracture is the most accurate answer as it addresses both the number of fragments and their orientation.