The structure indicated is the coccyx.
The coccyx forms the terminal aspect of the spinal column, and is comprised of three to five fused vertebrae. In humans and other great apes, the coccyx is the remnant of a vestigial tail. Superiorly, the coccyx articulates with the sacrum. On this superior surface is a facet for articulation with the sacrum, and also two processes which extend superiorly, known as cornua or horns.
On the lateral surface of the coccygeal vertebrae are transverse processes – this process is most prominent on the first coccygeal vertebrae. The coccyx contains no spinous processes, pedicles or laminae.
Coccygodynia as a painful condition of the coccyx, often following sudden impact on the coccyx following trauma from a fall, or from the pressure on the coccyx during childbirth in women.