Upper extremity fractures are among the most common of the extremity injuries with carpal fractures accounting for 18 percent of hand fractures and 6 percent of all fractures [1,2]. Of these, fractures to bones of the proximal carpal row are most frequent. The triquetrum is reported as the second or third most common carpal fracture representing 3 to 5 percent of all carpal bone injuries [3-5]. It is the second most common carpal fracture in sports.
This topic will review issues related to fractures of the triquetrum. A general overview of carpal fractures in adults is presented separately. (See "Overview of carpal fractures".)
The triquetrum is located just distal to the ulna and the triangular fibrocartilage complex and proximal to the base of the hamate (image 1 and figure 1). The triquetrum articulates on its radial side with the lunate to which it is attached by the lunotriquetral ligament. On the volar (palmar) aspect there is an articulation with the pisiform. The anatomy of the wrist is discussed in greater detail separately. (See "Anatomy and basic biomechanics of the wrist".)
MECHANISM OF INJURY
Triquetral fractures typically occur from a hyperextension injury with the wrist in ulnar deviation . Shearing forces exerted by the proximal hamate, distal ulna, or both may play a role. Injury can also occur with hyperflexion. In addition, either the dorsal or volar radiotriquetral ligaments may avulse triquetral fragments at their attachments .
Triquetral fractures may be divided into two types: