The coccyx, commonly known as the tailbone, is a small bone located at the very bottom of the spine. While often overlooked, this structure plays a role in supporting the body and serving as an attachment point for various tissues.
Pinpointing its Location
The tailbone is situated at the terminal end of the vertebral column, directly below the sacrum. To physically locate it, one can gently feel for the small, bony protrusion at the very bottom of the spine, where the buttocks meet. It is positioned at the apex of the pelvis, forming part of the pelvic floor’s bony framework, and helps bear weight when seated.
Structure and Connections
The coccyx is composed of three to five individual vertebrae that often fuse in adults, forming a single, triangular-shaped bone. This fusion usually begins in a person’s twenties and can be complete by age 30. Its base connects with the sacrum, the large triangular bone just above it, forming the sacrococcygeal joint. This joint allows for limited movement, such as slight flexion and extension.
The tailbone serves as an attachment site for numerous ligaments, tendons, and muscles that contribute to pelvic stability and function. Key muscles attaching to the coccyx include the gluteus maximus and components of the levator ani, a group of muscles forming the pelvic floor. Ligaments like the sacrococcygeal ligaments also connect the coccyx to the sacrum, providing further support.
Common Causes of Tailbone Pain
Pain in the tailbone, medically known as coccydynia or coccygodynia, can arise from various factors due to its exposed location and role in weight-bearing. A common cause is direct trauma, such as falling directly onto the buttocks, which can bruise, fracture, or dislocate the coccyx. Repetitive strain from activities like prolonged sitting, especially on hard surfaces, or certain sports like cycling, can also lead to inflammation and pain in the area.
Childbirth is another frequent cause of tailbone pain, as the process can put significant stress on the coccyx and its surrounding ligaments and muscles. Hormonal changes during pregnancy can also increase the flexibility of the sacrococcygeal joint, potentially leading to discomfort. Less common factors include poor posture, being overweight or underweight, or conditions like bone spurs. The pain can range from a dull ache to sharp, piercing sensations, often worsening with sitting or transitioning from sitting to standing.