Most frequently dislocated carpal bone?

Most frequently dislocated carpal bone?

• A. Capitate
• B. Trapezium
• C. Lunate
• D. Scaphoid

Answer: (C)

The thing this question tests is which carpal bone is most prone to dislocation when the wrist is injured. The lunate sits right in the center of the proximal carpal row between the distal radius and the rest of the carpal bones, and it’s stabilized by ligaments that can give way in a fall onto an outstretched hand with the wrist driven into hyperextension. When those radiocarpal ligaments fail, the distal row can shift in relation to the lunate, allowing the lunate to displace either palmarly into the carpal tunnel or dorsally with a perilunate pattern. Because of its central position and the way these ligaments can fail under common injury mechanisms, the lunate ends up being dislocated more often than other carpal bones. The scaphoid, by contrast, is more notorious for fractures than dislocations, and the other carpal bones are less commonly involved in dislocations.

The thing this question tests is which carpal bone is most prone to dislocation when the wrist is injured. The lunate sits right in the center of the proximal carpal row between the distal radius and the rest of the carpal bones, and it’s stabilized by ligaments that can give way in a fall onto an outstretched hand with the wrist driven into hyperextension. When those radiocarpal ligaments fail, the distal row can shift in relation to the lunate, allowing the lunate to displace either palmarly into the carpal tunnel or dorsally with a perilunate pattern. Because of its central position and the way these ligaments can fail under common injury mechanisms, the lunate ends up being dislocated more often than other carpal bones. The scaphoid, by contrast, is more notorious for fractures than dislocations, and the other carpal bones are less commonly involved in dislocations.