Which carpal bone is most commonly involved in carpal ligament instability?

The lunate bone is commonly involved in carpal ligament instability due to its central position in the carpal arch and its unique articulations with adjacent bones. The lunate acts as a keystone in the wrist, connecting with both the radius and other carpal bones. Its anatomical position makes it particularly susceptible to injuries, such as those associated with wrist fractures and dislocations.

Carpal ligament instability often results from ligamentous injuries that affect the stability of the bones surrounding the lunate, leading it to shift out of its normal alignment. This condition, known as carpal instability, can stem from trauma or repetitive strain, and the lunate's involvement in these injuries is significant due to the complexities of its movement patterns and the surrounding ligamentous structures, such as the scapholunate and lunotriquetral ligaments.

Understanding the role of the lunate in the context of wrist biomechanics and its interactions with other carpal bones helps to clarify why it is the most commonly involved bone in instances of carpal ligament instability.