Coccyx Pain

Excerpt

Multiple synonyms, including coccydynia, coccygodynia, and tailbone pain, are known as coccyx pain. Simpson introduced the term coccydynia in 1859, and 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 various modern options available to diagnose and treat coccydynia. Further, patients should be referred to a specialist if the etiology remains unclear or the patient fails to get adequate relief. The overall scope of treatment includes avoiding exacerbating factors (sitting), using cushions, taking oral or topical medications, and administering pain management injections under fluoroscopic guidance. Only a small percentage of patients with coccydynia require surgical treatment, which is coccyx resection (eg, coccygectomy).

Anatomy

The coccyx is the terminal region of the spinal column. Although "tailbone" implies that this is a single bone, it consists of 3 to 5 separate vertebral bodies, with substantial variability regarding whether they are fused. 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, 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 continue 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 buttocks) and the coccyx (in the midline). This tripod supports weight-bearing in the seated position. The nerves of the coccyx are not usually well described in anatomical textbooks, but 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 (see Images. Sacrum and Coccyx, Lateral Surface and Coccyx Vertebrae).