A coccyx injury is any condition that results in pain in or damage to the coccyx bone in the vertebral column. These typically include coccyx dislocations, fractures, or even bruises on the bone. Though sometimes considered a vestigial structure, the coccyx is necessary as a site of attachment for several major muscles. It is also what allows humans to sit in a backward-leaning position. Treatment of a coccyx injury is usually conservative, but may require removal of the tailbone all together, and while these conditions or their treatment may rarely be life-threatening, injury to or removal of this bone can severely limit movement and interrupt daily functioning.
Coccyx injury often presents with a condition known as coccydinia, which is localized coccyx pain. This pain is sometimes caused by injury to other areas. A doctor can determine if the coccyx itself is injured by anesthetizing the tailbone via injection to see if the pain diminishes.
Commonly reported injuries that result in coccyx pain are hypermobility, in which the coccyx bends more than it should to the front when a person is in a seated position. Another injury is posterior luxation, in which the coccyx partially dislocates to the back when the person is in a seated position. Finally, bone spurs on the coccyx are considered a coccyx injury. Causes of these injuries can range from sitting down too hard on the tailbone, to a fall, to repeated pressure on the area from activities like cycling or horseback riding. Any existing coccyx injury can be exacerbated by these same activities as well as by obesity.
Another type of coccyx injury caused by trauma to the region is a fracture. This typically happens as the result of acute impact, as in an abrupt fall into a sitting position or a strike to the bone. Bruises or dislocation of the coccyx can similarly occur as a result of these types of injuries. Prescribed treatment may include pain medication, icing, cortisone injections, and avoiding sitting on the region until discomfort diminishes and the injury has adequate time to heal. Surgery to repair damage to the coccyx is rare, as is removal of the bone.
Also known as the tailbone, the coccyx is not actually a single bone but made up of four stacked vertebral segments, though it can comprise as few as three or as many as five. Each segment is smaller and narrower than the one above it, so the coccyx tapers from top to bottom. Found at the base of the spine below the sacrum and projecting downward between the two iliac bones of the pelvis, the coccyx is where the large gluteus muscle originates, arising from the posterior surface of the bone and extending horizontally across the hip to either side. Its anterior surface is where the pelvic floor muscles — the coccygeus and levator ani group — originate. These muscles are critical to the processes of urination, defecation, and giving birth, as well as to the support of the reproductive and digestive organs of the pelvis.