The tailbone, or coccyx, is a small, triangular bone located at the base of the spine, where several muscles and ligaments attach. Pain in this region, known medically as coccygodynia, can be debilitating, often making simple acts like sitting difficult. Coccygodynia presents a diagnostic challenge because its source is frequently complex. Many people experiencing this persistent pain wonder if the discomfort stems from arthritis or joint degeneration.
Arthritis and the Sacrococcygeal Joint
The coccyx attaches to the sacrum via the sacrococcygeal joint, a fibrocartilaginous connection stabilized by ligaments. Like other joints, this structure can experience arthritic changes, though it is an uncommon primary cause of long-term tailbone pain. When present, the most frequent form is osteoarthritis, which is a wear-and-tear degeneration of the joint cartilage. This degeneration often occurs years after a specific injury or trauma, suggesting it is frequently a secondary condition.
Inflammatory arthropathies, such as Ankylosing Spondylitis, can also affect the sacrococcygeal joint, causing persistent discomfort. These conditions involve systemic inflammation that targets the body’s joints and entheses, the sites where ligaments and tendons attach to bone. However, mechanical instability or direct injury to the surrounding soft tissue is far more likely to be the initial trigger for pain. Arthritis is generally investigated only after more common mechanical causes have been ruled out.
Common Sources of Coccygodynia
The majority of chronic coccyx discomfort is mechanical in origin. Direct trauma, such as a backward fall onto a hard surface, is the most frequently identified cause, accounting for up to 70% of all cases. The impact can cause a fracture, dislocation, or inflammation of the surrounding ligaments and soft tissues.
Structural problems related to coccyx movement are another common issue. Hypermobility, where the tailbone moves too much when transitioning to sitting, creates excessive friction and inflammation. Conversely, hypomobility, where the coccyx is unusually stiff, prevents the natural shock absorption needed for movement. Prolonged sitting on hard or poorly padded surfaces can also create localized pressure, leading to chronic soft tissue inflammation.
The physical strain of childbirth can injure the coccyx or associated ligaments, sometimes causing temporary or permanent displacement. Pain may also be referred from other regions, notably the lumbar spine or tightness in the surrounding pelvic floor muscles. This referred pain means the source of the discomfort is not actually the coccyx itself, but another nearby structure.
Diagnosing the Origin of Coccyx Pain
Diagnosing the source of coccygodynia requires a systematic approach, beginning with a thorough physical examination. The clinician will palpate the area externally to check for localized tenderness, swelling, or potential bone spurs. An internal rectal examination may also be performed to assess the mobility and alignment of the coccyx and to rule out masses or other internal pathology.
Standard X-rays are typically insufficient because they only show the bone structure in a static position. Specialized dynamic X-rays are often necessary, taken with the patient standing and sitting. This dynamic imaging allows clinicians to measure the change in the coccygeal angle; movement greater than 25 degrees suggests mechanical hypermobility.
Magnetic Resonance Imaging (MRI) is used to rule out serious causes, such as infections, tumors, or abscesses in the surrounding soft tissue. A highly specific diagnostic tool involves injecting a local anesthetic directly into the sacrococcygeal joint or surrounding bursa. If the injection provides immediate, temporary relief, it confirms the injected structure is the primary source of discomfort, which helps guide long-term treatment.
Managing Chronic Coccyx Discomfort
Management of chronic tailbone pain begins with conservative measures designed to reduce mechanical pressure on the affected area. Specialized seating, such as donut or wedge-shaped cushions, helps redistribute body weight away from the coccyx when sitting. Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) can effectively reduce localized pain and inflammation associated with mechanical strain.
Physical therapy is a common first-line treatment, focusing on exercises that stretch and relax the often-tight pelvic floor muscles. Manual manipulation techniques may also be used to normalize the alignment and movement of the coccyx.
When conservative methods fail, interventional treatments are considered. Corticosteroid injections, mixed with a local anesthetic, are administered directly into the joint or surrounding ligaments for sustained relief. A targeted option is a ganglion impar nerve block, which interrupts pain signals transmitted by nerves supplying the coccyx region. Only in the most refractory cases, after all other conservative and interventional treatments have been exhausted, is a coccygectomy, or surgical removal of the coccyx, considered.