The scapho-trapezial-trapezoid (STT) joint is a common source of radial wrist pain. Osteoarthritis of the STT joint is very frequent. The ligament complex stabilizing the STT joint almost never receives attention at imaging. It has been anecdotically described that the key radiological investigation is the arthrogram of the midcarpal joint with contrast media communication from the STT joint into the tendon sheath of the flexor carpi radialis tendon allowing the incident diagnosis of the STT ligament complex tear.
This new study adresses the anatomy of the MRI-Anatomy of the STT ligament:
The complex can consistently be visualized on high-resolution 3D MRI.
Schematic illustration of the 4 components of the scapho-trapezial-trapezoidal ligament from different perspectives (a: from palmar, b: oblique view from ulnopalmar, c: lateral view from radial). Green: radiopalmar scapho-trapezial ligament (rpSTL), yellow: palmar scapho-trapezial-trapezoidal capsule (pSTTC), red: palmar scapho-capitate capsular ligament (pSCL), blue dorsal scapho-trapezial-trapezoidal capsule (dSTTC)
Contrast media in the tendon sheath of the flexor carpi radialis tendon. Fluoroscopic image (a) of contrast media in the tendon sheath of the flexor carpi radialis tendon (white arrows) after midcarpal contrast media injection as an indirect sign of a tear of the STT ligament complex. Corresponding axial (b) (proton density with fat saturation) and sagittal (c) (T1 weighted with fat saturation) MR images also show contrast media (white arrows) in the tendon sheath of the flexor carpi radialis (white star). S, scaphoid; L, lunate; R, radius; T, trapezium