Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier’s disease is a common entity among elderly and is characterized by ossification of the anterior longitudinal ligament (ALL) of the spine and various extraspinal ligaments. The pathogenesis of abnormal bone growth in DISH is not fully understood. In an attempt to figure out an anatomical explanation of the etiology of such a debilitating disease, the present study investigated the role of blood supply of the ALL. In cadavers of the anatomy lab in Libyan International Medical University, fine dissection of vessels supplying ALL was performed in the vicinity of azygos, hemiazygos veins and descending thoracic aorta; starting from the level T5 till T12 vertebrae. The current work elucidated that the blood vessels supplying ALL ran in ascending manner ranging from oblique to nearly vertical in direction. The present study demonstrated that poor blood supply reaching certain regions of the spine caused by antigravity‐directed blood vessels supplying ALL, may lead to ischemic changes caused by hypoperfusion and thereby ossification of ALL leading to DISH disease. The current results open a new era of investigation of the probable etiology of this disease. Grant Funding Source: Supported by the Libyan International Medical University