Sitting below the sacrum at the lowest part of the spine is the coccyx, also known as the tailbone. It is a small triangular bone resembling a shortened tail and comprises 3 to 5 spinal bones or coccygeal vertebrae with disc-like ligaments.
Doctors believed the coccyx was always fused or semi-fused, but there was limited movement between the bones permitted by fibrous joints and ligaments. Injuries are common, often resulting from slips, trips or falls or childbirth.
The function of the coccyx
- Although the tailbone is no longer necessary in the human body, it still has roles in the pelvis and the sitting bones (ischial tuberoses); it supports bearing weight in sitting.
- The coccyx provides an attachment point for many pelvic floor muscles; the muscles support the contents of the pelvis, including the anus and vagina in women.
- When we sit or stand, the bones that make up the pelvis, including the coccyx, rotate outward and inward to better support and balance the body. The coccyx usually moves slightly forward or backwards as the pelvis, hips, and legs move.
What is coccyx pain?
Coccydynia is the medical name for coccyx or tailbone pain, also known as coccygeal pain. It results from damage to the bones or the surrounding tissues becoming inflamed; the discomfort or pain at the base of the spine is noticeable when sitting down or getting up from a seated position.
People with coccydynia often describe a dull, achy pain and tenderness at the tip of the tailbone, deep between the buttocks above the anus; sitting often worsens coccyx pain.
Depending on the cause, symptoms may sometimes include muscle weakness, loss of sensation, digestive discomfort, and pain in the rectum.
Who gets it? Are you at risk?
There are several common risk factors, including:
- Coccydynia is much more common in women because their pelvic anatomy means they are more likely to place weight on the coccyx when sitting, leaving it more susceptible to injury.
- Pregnancy and childbirth are the most common causes of coccyx pain in women; during pregnancy and labour, the pelvis, including the sacrum and coccyx, become more flexible to allow movement during the delivery if the muscles and ligaments around the coccyx become overstretched and irritated, resulting in postnatal discomfort and pain.
- Pelvic floor muscles dysfunction can also result in coccyx pain.
People can injure their coccyx from an impact on a hard surface or trauma to the base of the spine; for example, skiing, skateboarding, and horse riding are repetitive sports with high risks of falls. And any slip or trip falling backwards onto one’s bottom can injure it. In most cases, this results in bruising, but it’s possible to dislocate one joint in the coccyx or sustain a fracture.
Some sporting activities can put people at risk of a repetitive strain injury (RSI); for example, rowing, cycling, horse riding. But any sport or activity that involves putting pressure on or involves continual motion of stretching the base of the spine or leaning forward can strain the muscles and ligaments around the sacrum and the coccyx.
Poor sitting posture
Sitting on a hard chair or with added weight on your lap, such a child or heavy bag can put increased pressure on the coccyx. Also, slumping in chairs, sofas or car seats, sitting in awkward positions, and being seated for extended periods can irritate the bones and surrounding tissues.
Coccydynia is a risk for very slim or underweight people as they may not have enough buttock muscles or fat to protect their coccyx from friction or rubbing.
Being overweight or obese can also put extra pressure on the coccyx when sitting down and result in coccydynia or make an existing condition worse.
Degeneration or osteoarthritis
Trauma-related degeneration or age-related spinal osteoarthritis can also affect the bones of the coccyx and the discs that help hold the coccyx in place and cause pain.
Although rare, coccyx pain can be the sign of a disease at the base of the spine or the soft tissues surrounding it.
Diagnosis & Treatment
- Diagnosis starts with and an examination of the external tailbone area to check for any visible bruises. Sometimes an internal investigation is needed to assess the bones; this is done through the anus (back passage) with one gloved finger.
- X-rays and MRI scans may be needed to rule out some of the more serious conditions.
- A tailbone injury can be excruciatingly painful and slow to heal. Recovery depends on the severity of the injury; expect bruising to recover in four weeks and a fracture between 8 – 12 weeks.
- Doctors will usually prescribe painkillers or anti-inflammatory medication. If the pain persists, other treatments may be required.
- Manual treatment such as osteopathy can be helpful; because tightness in some muscles can contribute to symptoms; such as buttock muscles (Gluteal and Piriformis), the inner thighs (Adductor Magnus)
- Some doctors and physical therapists will recommend an internal release of the coccyx via the anus; this is a quick, painless procedure that can give instant relief.
- Orthopaedic surgeons can inject corticosteroids into the painful joint or offer nerve blocks.
If conservative treatments cannot relieve the pain, the coccyx may need to be removed entirely in a coccygectomy operation. Medical literature recommends that conservative treatment be tried for between three and eight months before surgery is considered. The procedure is relatively straightforward, but it is rarely performed because the recovery can be long, up to 12 months, and very uncomfortable.
- Sitting is the primary aggravating factor; using a coccyx wedge cushion can be helpful; it has a cutout at the back, so the tailbone is free of weight-bearing.
- Avoiding constipation and keeping the stool soft is essential for people who experience coccyx pain with bowel movements and staying hydrated, and getting enough fibre in the diet.
- Alignment and posture play a significant role in relieving the stress of the coccyx. People are often unaware of how they may irritate their coccyx while doing simple daily activities such as sitting at work, riding their bike or watching their favourite TV programme relax on their sofa.
Although there is no simple way to prevent coccyx pain because accidents can happen entirely, most cases are not usually permanent, but some can persist and become chronic coccydynia if not controlled, treated and managed with lifestyle measures to reduce the pressure causing the irritation or strain in the area.