A severe case of kyphoscoliosis was observed in the skeletal remains of a male from the late Edo period in Japan. This individual exhibited left curvature thoracic scoliosis and kyphotic deformity, with ankylosis of the fifth to twelfth thoracic vertebrae at the intervertebral joints. The Cobb angle was 77° and the kyphotic angle was 76°. The superior articular facet of the cervical vertebrae was lower on the left side than the right side. Additionally, the sacral base was inclined to the right, resulting in the superior articular process and facet being lower on the right than on the left. These observations suggest compensatory right curvature of the cervical and lower lumbar spine. The rib morphology was asymmetrical, with the right ribs being obtusely angled and spreading laterally, while the left ribs were acutely angled and directed medially. These findings indicate that this individual had severe structural left-convex thoracic kyphoscoliosis. The possible underlying conditions considered in this case included idiopathic scoliosis or syringomyelia. This is the first detailed report of severe kyphoscoliosis in archaeological skeletal remains excavated from the Japanese Archipelago.

Dental wear refers to the gradual loss of dental hard tissues, and its patterns are greatly af‍fected by dietary habits. This study examined dental wear in the Jomon people, prehistoric hunter-gatherers of the Japanese archipelago, to determine whether molar wear rate was relatively fast or slow compared with that of other hunter-gatherer populations with different dietary habits. To evaluate the rate of dental wear, we used average score differences between adjacent molars. Considering that this parameter is independent of age, we compared the Jomon wear rate value with those of the other hunter-gatherers and pastoralist populations available in the literature. Results indicated that the Jomon people had a significantly lower rate of wear compared to populations in arid regions with a higher reliance on abrasive plant-based diets. Furthermore, the Jomon wear rate was comparable to or lower than that of populations in cold climate with less dependency on plant foods. We suggest that the low rate of wear seen in the Jomon people stems from the use of pottery, accompanied by an increased reliance on carbohydrates, possibly associated with changes in cooking methods.