To observe and describe the development and underlying structure of the spinal manifestations of individuals osteologically diagnosed with DISH (Diffuse Idiopathic Skeletal Hyperostosis), using micro-XCT imaging. A total of 72 individuals with DISH were identified in two modern skeletal collections in South Africa. Vertebral columns affected by DISH were scanned at the micro-focus x-ray computed tomography facility at the Nuclear Energy Corporation of South Africa. Four features were macroscopically examined: (1) the origin of the new bone growth; (2) retention of the original vertebral cortex at the site of the new bone formation associated with DISH; (3) evidence of trabecular bone with or without sclerosis on the anterolateral surface of affected vertebrae; and (4) abnormal areas of osteosclerosis beyond features associated with DISH. Considerable variation across and between the four recorded features was found. Of note, 81% (n = 58) of individuals had both developed trabecular bone within the flowing new bone formation (feature 3), without retention of the original vertebral cortex (feature 2). Possible localised erosive/inflammatory processes destroyed the original cortex of the vertebral body and resulted in the expansion of trabeculae with new bone formation. Micro-XCT imaging shed new light on the development of DISH, adding to literature suggesting that it could be an inflammatory disease. Clinical histories of the individuals were not known. The role of chronic inflammatory disease in the development of DISH should be further explored including both the extra-spinal and spinal manifestations.