![]() ![]() On the ulnar side, the disc has band-like fibrous attachments to the ulnar styloid and the fovea. The TFCC is composed of a triangular-shaped articular disc of fibrocartilage, which parallels the articular surface at the ulnocarpal joint with an attachment to the ulnar margin of the distal radius where the disc attaches directly to the articular cartilage of the distal radius. The dominant stabilizing structure of the wrist is the triangular fibrocartilage complex (TFCC), located on the ulnar aspect of the wrist. For example, the scapholunate ligament attaches the scaphoid with the lunate, referencing the specific carpals spanned from radial to ulnar direction. Typical nomenclature of the ligaments describes the structures connected and the direction of their attachment either proximally to distally or from the radial to ulnar aspect. Each bone has specific connections to adjacent osseous structures that provide the overall balance of stability and movement for the wrist. Īn intricate array of intrinsic (carpal to carpal) and extrinsic (radius and ulna to carpal) ligaments binds the osseous structures and allows for compound motions. The various articulations of the osseous structures of the wrist, which include long bones, carpals, and metacarpals, provide a wide range of motion, including various combinations of flexion, extension, ulnar, and radial deviation, supination, and pronation. Together with synovial joint fluid, the hyaline cartilage provides a low friction surface for movement across joints and aids in shock absorption. The articular surface of osseous structures is covered with articular (hyaline) cartilage, a connective tissue composed of a dense network of collagen fibers resulting in tissue with tensile strength yet more flexible than bone. The complexity of this three arc system creates multiple synergistic joints that allow the wrist a dynamic range of motion. The osseous anatomy of the wrist includes the distal radius and ulna, eight carpal bones, and the five metacarpals (Figure 1). The purpose of the article is to provide insight into the various imaging modalities as they relate to imaging of the wrist in diagnosing pain and dysfunction from different types of pathology. We are now fortunate to have advanced imaging techniques to assess and diagnose the pathology of this complicated anatomic structure. Perhaps it is no coincidence that the first human radiograph taken in 1895 by William Roentgen was that of the hand and wrist, though far from diagnostic in such primitive form. Trauma or other pathology, including degeneration, to any of these structures, can cause a wide range of pain and dysfunction that may not be easily diagnosed due to the inherent anatomic complexity. The radial and ulnar arteries, as well as their terminal branches, provide vascularity to the hand and wrist while the median, ulnar, and radial nerves are responsible for motor and sensory innervation. As with other joints, numerous ligaments and tendons connect and provide structural stability and movement of the osseous structures of the hand and wrist. Made up of eight carpal bones, the radius, ulna, and five metacarpals, the number of articulations and degrees of motion are quite extensive. ![]() Categorically considered a hinge joint like the elbow, the wrist has additional planes of movement and rotation thanks to robust anatomy. However, they found that the lateral radiographs were not more accurate than the PA radiographs (Derek Bernstein, 2018).The wrist is one of the most complex joints in the human body, allowing for stability during movement in all three cardinal planes of the human body. In an article published in the Journal of Hand Surgery, they evaluated the use of the lateral radiograph in measuring ulnar variance. Posteroanterior radiographs of the wrist are the best projection to measure ulnar variance (Judy Squires, 2014). A negative ulnar variance is when the ulna surface is shorter than the radial surface and a neutral variance is when the radius and ulna surfaces are at the same height (Luis Cerezal, 2002). A positive ulnar variance is when the ulna surface is higher than the radial surface. Ulnar variance is measured by drawing a straight line across the distal ulna, drawing another straight line across the distal radius, and then measuring the length between them (Andrew Parker, 2014). These can include TFFC tears, Kienbock disease, and DRUJ instability (Derek Bernstein, 2018). Ulnar variance should be evaluated in all wrist x-rays, because an increased ulnar variance is associated with multiple wrist pathologies. Radiologists will also attempt to measure certain angles to evaluate for radius shortening (Jack Porrino, 2014). ![]()
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