Severe kyphoscoliosis observed in a human skeleton from the Edo period

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.