CAMRT Radiography Practice Exam

What type of fracture is characterized as an oblique fracture of the base of the first metacarpal?

1. Colles' fracture

2. Bennett's fracture

3. Smith's fracture

4. Greenstick fracture

The correct answer is: Bennett's fracture

A Bennett's fracture is specifically identified as an oblique fracture through the base of the first metacarpal, which corresponds to the thumb. This type of fracture typically occurs with a compressive force or axial loading on the thumb, often resulting from trauma such as a fist striking a hard object. The oblique orientation of the fracture line is crucial in defining this injury, as it distinguishes Bennett's fracture from other types of fractures that may occur in the wrist or hand. In addition to being oblique, Bennett's fracture is notable for the involvement of the carpometacarpal joint, which can lead to joint instability if not properly treated. Surgery may be required to secure the fracture fragments, restore alignment, and prevent complications such as arthritis. The other types of fractures mentioned do not share these specific characteristics: a Colles' fracture typically involves the distal radius and is characterized by dorsal angulation; a Smith's fracture also affects the distal radius but with palmar angulation; and a Greenstick fracture is an incomplete fracture often seen in children, characterized by bending and partial breaking of the bone rather than a complete oblique fracture.