Purpose The development of dry arthroscopic examination of the distal radioulnar joint (DRUJ) has changed our understanding of the anatomy of triangular fibrocartilage (TFC) tears. This paper aims to improve understanding of the anatomy and prevalence of TFC tears associated with DRUJ instability. Methodology A retrospective audit was conducted on all patients with symptomatic DRUJ instability who underwent dry arthroscopy of the wrist and DRUJ performed by the primary author over 12 months in 2020. Patients who did not have a tear of the TFC identified at arthroscopy or who exhibited signs of ulnocarpal impaction were excluded from the study. A description of the anatomy of the TFC tear and the result of the hook test was documented for all patients. Results A TFC tear was identified in 107 patients. All patients had a peripheral tear of the TFC. A partial tear of the foveal ligament was identified in 11 patients (10.3%) and a complete tear of the foveal ligament in 2 patients (1.9%). 2 patients had a complex tear of the TFC including a horizontal shear tear and a volar tear which extended into the lunotriquetral joint. Conclusion Dry arthroscopy of the RCJ and DRUJ is necessary to accurately evaluate the integrity of the foveal ligament. This study revealed that all tears of the TFC associated with DRUJ instability have a peripheral component and with increasing severity the tear extends between the floor of the ECU sheath and the foveal ligament. In the most severe expression of the injury, the foveal ligament is damaged (10%) and rarely is the foveal ligament completely torn (2%). The ability to define the anatomy of the TFC tear will enable surgeons to perform anatomically specific repairs.