Background: The tendons of Abductor pollicis longus and Extensor pollicis brevis pass through the first compartment of the extensor retinaculum. These tendons pass with their own synovial sheaths and sometimes they share a common synovial sheath which can be septate. Constant friction between these tendons in a living person results in tenosynovitis. Aim: This study aimed to document the relationship between the tendons and the bone and variations in the tendon or the bone could produce any significant contribution to the outcome of disease. Materials and Methods: 100 radius bones of both sides were sourced for the study to measure the length, breadth and depth of the extensor groove using a Vernier caliper and the same were documented. Results: The mean length, breadth and the depth of the grooves were more on the right side than the left side. In a significant percentage, the ridge was absent. Conclusion: The morphometric data will provide an insight for corrective surgeries in tenosynovitis and for corticosteroid injections in cases of tenosynovitis.