Origin of the uncus and of Luschka's joint in the cervical spine.

In the third through seventh cervical vertebrae, the lateral one-quarter of the body is originally part of the neural arch and is formed slightly cephalad to the rest of the vertebral body. After excavation of the superior vertebral notch, the osseous prominence that remains is the uncus. The intervertebral disc is limited to the area between the anlagen of the vertebral bodies, and the portion of the intervertebral space that is lateral to the disc is occupied by loose fibrous tissue. When this tissue is resorbed it leaves a space that constitutes Luschka's joint. These anatomical findings are based on dissections of forty-five specimens comprising human fetuses and autopsy material from individuals who ranged in age from eight days to eighty-nine years.