Injuries that involve tearing or stretching of the ligaments of your fingers are termed as sprains. Sprains in the fingers are most often caused from a fall when you extend your arms to reduce the impact of the fall, or from overuse or repetitive activity of the thumb such as with texting.
A ligament is a strong, flexible band of fibrous tissue. The wrist has many ligaments that help to keep the wrist bones in proper position providing stability to the joint. A torn ligament causes the wrist bones to move out of their position, which in turn leads to wrist instability as the sprained (torn) ligament can no longer support the wrist bones.
Triquetrolunate instability is the instability that takes place between the triquetrum or medial column and the lunate bones or the central column of the wrist. The triquetrum and the lunate comprise the ulnar side of the proximal carpal row at the wrist. This joint is supported by the lunotriquetral (LT) ligament.