The scapholunate ligament is the most commonly injured ligament in the wrist, usually the result of a fall on an outstretched hand. The scapholunate ligament is an intrinsic ligament binding the scaphoid and lunate together between the proximal and distal rows of carpal bones. Scapholunate dissociation is diagnosed radiographically with a widening of the scapholunate space greater than 3 mm. This is also known as the Terry Thomas sign.
Injuries to the triquetrolunate ligament are less common, and usually result from a fall onto an outstretched and dorsiflexed hand. This injury may produce pain on the ulnar aspect of the wrist and can be confused with injury to the triangular fibrocartilage complex.
The Space of Poirier refers to the area between the two palmar arches at the junction of the capitate and lunate, and is vulnerable to ligamentous disruption.