What Exactly is the Tailbone?
The tailbone is the smallest and lowest bone in the spinal column. It forms the lower end of the vertebral column, situated beneath the sacrum. Typically, it consists of four vertebrae (Co1- Co4) that fuse to form a triangular shape, resembling a shortened tail. Since it is a vestigial tail, it is commonly referred to as the tailbone. The tailbone is one of the bones responsible for bearing the body’s weight when sitting.
Where Can the Tailbone Be Found?
The tailbone is located at the most distal part of the spine, just below the sacrum. It is the bottommost segment of the pelvic girdle or pelvis.
Interesting Facts
| Type | Irregular bone |
| Length | Approximately 1 inch |
| Total in the human body | 1 |
| Articulates with | Sacrum |
Roles
Weight distribution while sitting: When seated, the body weight is distributed between the lower parts of the two hip bones (ischium) and the tailbone, thus ensuring balance and stability.
Structure
The tailbone has an inverted triangle shape, with a broad top and a pointed bottom. It also features several other significant bony landmarks.
Bony Structures
In addition to the top and bottom, it also possesses an anterior surface, posterior surface, and two lateral surfaces.
Front Surface
The front surface of the tailbone is slightly concave and marked with three transverse grooves indicating the connections of the four vertebrae. The anterior sacrococcygeal ligament attaches here.
References
- The Coccyx – Teachmeanatomy.info
- Anatomy, Back, Coccygeal Vertebrae – Ncbi.nlm.nih.gov
- Coccyx – Radiopaedia.org
- Coccyx – Innerbody.com
