Vertebral assimilation was observed in an adult male Ainu skeleton from the Tokoro Chashi site of the early modern period in Tokoro, Hokkaido, Japan. The vertebral bodies and right zygapophyseal joint between the 12th thoracic and 1st lumbar vertebrae were completely united by osseous tissue, with anterior wedge shape and 42% loss of anterior vertebral body height. Differential diagnosis suggested that this was a healed state of pyogenic spondylitis.
