A paracondylar process and early onset cervical osteoarthritis in a California Amerind adult

Burial 65 is a 25-39-year-old male from a hunter-gatherer California Amerind collection with a large bone spur called a paracondylar process. The process measures 11.92mm in width and 13.32mm in length. It is located on the left anteromedial region near the foramen magnum and articulates with a pseudarthrosis to the atlas. The atlas, too, has a pseudarthrosis¹ on the left transverse process. The paracondylar process may be the result of caudal occipitalization, which is a congenital variant that results from a lack of fusion of the occipital bone to the foramen magnum. Trauma is another possible explanation for the occipital-atlas variation. High-impact accidents can cause both atlas and condylar fractures. Regardless of the cause, the paracondylar process and pseudarthrosis likely caused early onset cervical osteoarthritis.