Which carpal bone is second most commonly fractured and is the most commonly dislocated?

Which carpal bone is second most commonly fractured and is the most commonly dislocated?

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

Answer: (B)

In wrist injuries, two patterns you should remember are that the scaphoid is the most commonly fractured carpal bone, and the lunate is the most commonly dislocated carpal bone. The bone in question fits both clues: it is the second most commonly fractured among the carpal bones and, more notably, it is the most commonly dislocated. The lunate sits at the center of the proximal carpal row and is stabilized by several ligaments. When a force drives the wrist into hyperextension, these ligaments can fail and the lunate can be displaced from its normal position. This displacement disrupts the carpal arcs and often takes on a perilunate pattern, sometimes compressing structures in the carpal tunnel and causing median nerve symptoms. Because of its position and ligamentous attachments, the lunate is particularly prone to dislocation, making it the most common carpal dislocation. Fracture-wise, lunate fractures are less common than scaphoid fractures, which is why the lunate being second most fractured aligns with the typical distribution after scaphoid. Other carpal bones like the capitate or trapezium are injured far less often, so they’re not the usual answer in this scenario.

In wrist injuries, two patterns you should remember are that the scaphoid is the most commonly fractured carpal bone, and the lunate is the most commonly dislocated carpal bone. The bone in question fits both clues: it is the second most commonly fractured among the carpal bones and, more notably, it is the most commonly dislocated.

The lunate sits at the center of the proximal carpal row and is stabilized by several ligaments. When a force drives the wrist into hyperextension, these ligaments can fail and the lunate can be displaced from its normal position. This displacement disrupts the carpal arcs and often takes on a perilunate pattern, sometimes compressing structures in the carpal tunnel and causing median nerve symptoms. Because of its position and ligamentous attachments, the lunate is particularly prone to dislocation, making it the most common carpal dislocation.

Fracture-wise, lunate fractures are less common than scaphoid fractures, which is why the lunate being second most fractured aligns with the typical distribution after scaphoid. Other carpal bones like the capitate or trapezium are injured far less often, so they’re not the usual answer in this scenario.