Which structure corresponds to letter (D) in a typical cervical spine radiograph?

In a typical cervical spine radiograph, the intervertebral disc is the structure that corresponds to the specified location. The intervertebral disc is located between adjacent vertebrae and plays a critical role in providing cushioning, support, and flexibility to the spine. It consists of a gel-like center called the nucleus pulposus, encased by a tougher outer layer known as the annulus fibrosus.

On radiographs, the intervertebral discs appear as darker spaces between the vertebrae due to the different tissue densities—soft tissue of the disc versus the bony structures of the vertebrae. They are essential for maintaining the health and mobility of the cervical spine, as they allow for movement while also absorbing shock during activities.

Understanding the placement and appearance of intervertebral discs on radiographs is crucial for accurately diagnosing various spinal conditions, such as disc herniation or degeneration, which can significantly affect the overall health and function of the cervical spine.