Coccyx Pain

Excerpt

Coccyx pain is known by multiple synonyms, including coccydynia, coccygodynia, and tailbone pain. Simpson introduced the term coccydynia in 1859. Foye has referred to coccyx pain as the "lowest" (most inferior) site of low back pain.

There are many causes of coccygeal pain, ranging from musculoskeletal injuries (such as contusions, fractures, dislocations, and ligamentous instability) to infections (osteomyelitis) and fatal malignancies (such as chordoma).

Although many cases are self-limiting and resolve with little or no medical treatment, other cases are notoriously persistent, are challenging to treat, and are associated with severe and disabling chronic pain. Patients often report difficulty getting a specific diagnosis for the cause of their coccyx pain and note that their treating clinicians seem dismissive of this condition.

Clinicians should understand the wide variety of modern options available to diagnose and treat coccydynia. Patients should be referred to a specialist if the etiology remains unclear or if the patient fails to get adequate relief. The overall scope of treatment includes avoiding exacerbating factors (sitting), use of cushions, oral or topical medications, and pain management injections performed under fluoroscopic guidance. Only a small percentage of coccydynia patients require surgical treatment, which is amputation of the coccyx (coccygectomy).

Anatomy

The coccyx is the terminal region of the spinal column. Although the singular term "tailbone" implies that this is a single bone, it actually consists of 3 to 5 separate vertebral bodies, with substantial variability regarding whether they are fused or not. The coccyx articulates with the sacrum through a sacrococcygeal joint (including a fibrocartilaginous intervertebral disc and bilateral zygapophysial [facet] joints). The sacrococcygeal and intra-coccygeal joints allow for a modest amount of coccygeal movement, which is typically forward flexion while weight-bearing (sitting). The coccyx is a Greek word that means the beak of a cuckoo bird as the side view of the tailbone resembles the side view of a cuckoo bird's beak.

On the anterior surface of the coccyx, the following muscles gain attachment: levator ani, iliococcygeus, coccygeus, and pubococcygeus. On the posterior coccygeal surface, the gluteus maximus is attached. Also attached to the coccyx are the anterior and posterior sacrococcygeal ligaments, which are a continuation of the anterior and posterior longitudinal ligaments. Bilateral attachments to the coccyx include the sacrotuberous and sacrospinous ligaments. Besides being an insertion site for these muscles and ligaments, the coccyx is also attached to the anococcygeal raphe (which extends from the anus to the distal coccyx, holding the anus in its position within the pelvic floor).

Functionally, a tripod is formed by the bilateral ischial tuberosities (at the right and left inferior buttock) and the coccyx (in the midline). This tripod supports weight-bearing in the seated position. The nerves of the coccyx include somatic nerve fibers and the ganglion impar, which is the terminal end of the paravertebral chain of the sympathetic nervous system. The plural of the coccyx is coccyges or coccyxes.