Coccygodynia (Coccalgia)

Coccygodynia is also termed Coccalgia, Coccidynia and even Coccygeal Neuralgia or simply the term tail bone pain, to describe the symptoms of pain occurring in the region of the coccyx. The name Coccyx is derived from the Greek” cuckoo” because of its shape like a beak. It is attached loosely to the sacrum while different muscles are attached on it like the Gluteus Maximus, the Levator Ani, the coccygeal muscle and the sacrococcygeal ligaments. We will talk a little longer about them soon.

Often the pain is triggered by the sitting position and may be felt from the sitting to the standing position. Most cases seem to resolve in a few weeks or months. Unfortunately, the pain can become chronic and may impend on the quality of life. Management can become difficult when dealing with the nature of the pain in the coccygeal area. Radiographic studies can help appreciate pelvic rotation. Bone scans and Magnetic Resonance Imaging are useful in showing inflammation and edema. Dynamic Radiographs in standing and sitting positions can demonstrate excessive motion between the sacrum and the coccyx. Even a Sacro-Coccygeal discogram can be performed under fluoroscopic guideline.  

Let us review a little the bony anatomy: The Coccyx is a triangular bone which form the most distal segment of the human spine. It is composed of 3 or 5 coccygeal segments fused together to form generally a single bone. Often the first segment may not be fused to the second vertebra. The ventral portion of the coccyx is concave in shape while the dorsal portion is convex with the first coccygeal vertebra showing articular processes as part of the coccygeal cornua articulating with a sacral cornua present on the inferior aspect of the S5 vertebra. A synovial joint can be present or the articulation may form a symphysis allowing the exit of the dorsal branch of the fifth sacral nerve (S5).

For many anatomists, the tailbone is vestigial in the human body but it does have a function in the pelvis. It supports a person in the seated position while the weight is distributed between the ischium and the tail bone. providing balance and stability. It is a connecting point for many pelvic floor muscles supporting the anus and helping in the defecation and supporting the floor of the vagina in the females. It also assists in ambulation, and running activities as well as in the motion of the legs. 

Many muscles and ligaments insert on the coccyx like anteriorly the Levator ani muscle and the Sacro-coccygeal ligament. On the lateral border, the coccygeal muscles, the sacrospinous ligament, the Sacro-tuberous ligaments and the Gluteus Maximus muscles. Inferiorly, the tendon of the Iliococcygeus muscles which insert on the tip of the coccyx. Together, these ligaments and muscles contribute to the voluntary control of the bowel and provide support to the pelvic floor. The Coccyx and the Ischial tuberosities provide the main weight-bearing support once an individual is in a sitting position or lean back from a sitting position, increasing the pressure and the stress. Finally, the coccyx support also the annus.

Anterior and Posterior aspect of the Sacrum, Coccyx and the Sacro-coccygeal joint

Coccygodynia is related to a sudden impact to the coccyx following a fall especially in a saddle position or in relation to intense pressure sustained during childbirth at the birth canal. Partial dislocation at the sacrococcygeal synchronosis can be appreciated as well as an abnormal motion in relation to repetitive trauma to the local ligaments and muscles of the pelvic floor. A woman body secretes also hormones that soften the pelvic floor especially the areas between the sacrum and the coccyx, enabling the coccyx to move during childbirth. This may be a natural process but the muscles and ligaments become stretched and may become a source for residual pain.

A chronic stage of inflammation can create pain out of proportion. The reason such phenomenon is seen is not well understood but a high body mass especially in obese individuals as well as other factors like age and gender have all been studied to understand the problem. It was demonstrated that Obesity was able to force a greater intrapelvic pressure when prolonged sitting condition is imposed, even creating at time a possible posterior dislocation at the sacrococcygeal joint and forcing the coccyx to displace anteriorly.

Some sport activities like rowing or bicycling may require to lean back and forth while stretching the spine and in doing so, more pressure is applied to the pelvic area and the coccyx. Inversely, if you do not have enough fat in the buttocks area preventing your coccyx from rubbing, you may also experience pain and discomfort in the soft tissues of the pelvic floor. Rarely a malignancy can affect the area especially a Chordoma which represent the most common malignant primary bone tumor in an adult spine. This is a rare tumor but suspicion of such pathology needs to be kept in mind when dealing with pain in the area. Finally, coccyx pain also can also be seen as a complication related to a lumbar herniated or a degenerative disc disease or any spinal post-operative complications. 

The risk of “Coccygodynia” is 5 times higher in females than males, more common in adults and adolescents than children. It can be also classified as post-traumatic or non-traumatic (idiopathic). The post-traumatic coccygodynia result from an internal or external trauma especially when falling backwards which can result in a fracture of the coccyx or from childbirth injury already described above. A state of hypermobility or hypomobility of the sacrococcygeal joint can also be a cause. The radiological type 2, 3 and 4 are more often symptomatic than the type 1. In the absence of any pathology in the coccyx, spasticity itself can be the cause with pelvic muscles shifting it to an abnormal position. Brief, in more than one third of the patients, there is no cause for the pain. The classification of Postacchini and Massobiro is the most often used:

 Postacchini and Massobiro published in 1983 an article classifying 4 types  configurations of the Sacro-coccygeal joint:

Type 1: A coccyx slightly curve forward with an apex downward positioned.

Type 2: An exaggerated forward curvature of the coccyx with the apex in a straight forward position.

Type 3: A coccyx sharply angulated forward.

Type 4: A sub-luxation of the coccyx at the sacrococcygeal joint

Grading of Coccygodynia

In approaching a patient with coccyx pain, a complete medical history must be collected starting with the physical examination and the symptoms. Environmental factors and life style with exercises habits or Obesity. Palpate for local tenderness around the coccyx to identify area of swelling and tenderness. A rectal examination is necessary for you to appreciate the tonus and the functionality of the rectal sphincter, the presence of any bone spurring over the coccyx, as well as the mobility or the stability of the Sacro-coccygeal joint (SC), any bony or soft tissue masses, abscesses, bone defects etc. Palpate the Lumbosacral spine in appreciating the midline aspect spinous processes L3, L4, L5, S1, the paravertebral muscle looking for masses and the vertebral interspace of the lower lumbar spinal area. Appreciate the presence or the absence of the spinous process to rule out the existence of any Spina Bifida condition. in search of deformity or pain. Standing behind the patient while he/she is in standing or laying down, in a prone or a lateral decubitus, will allow you to evaluate truly the lower spine. Perform a rectal examination. Appreciate any motion at the SC joint.                    

The pain may be described as a pulling or cutting sensation and often one can be tender at mobilization of the coccyx or they may sit in a way that their weight bearing is off the coccyx. Pain can be alleviated when sitting on the legs or the buttocks. Pain is felt also at defecation or the urge of defecation may release the pain while pain can be exacerbated with coughing or even menstrual periods. Pain may worsen with constipation and relieve after a bowel movement. Sexual interact can be also painful (Dyspareunia). Often, people suffering from Coccygodynia can also suffer from depression, anxiety, lack of sleep. We did mention fractures and tumors in the pelvic floor and we would like to add also Infections like a perianal abscess, rectal carcinomas and other rarer pathologies.

Lateral Decubitus and rectal examination to appreciate mobility and pain at the SC joint.

Palpating the coccyx itself through a rectal examination, is better to appreciate coccygodynia than palpating the coccyx through the skin. You can appreciate if you are dealing with a referred pain from the visceral organs (pseudo-coccygodynia)) or from the peripheral nerve roots or plexus (radiculopathy) which can be referred or directed to the buttock area, the thigh, hip and back areas (Psychogenic coccygodynia). Often, the straight leg raise test is also positive creating pain.

Most patient will recover from the pain and discomfort of a Coccygodynia although they will use their home remedies prior to see a physician. There is the anti-inflammatory medication found on the counter like the NSAID (Advil, Motrin, Ibuprofen, Naprosyn) are routinely taken to reduce the inflammation in avoiding too much sitting position. Hot baths in using also Jacuzzi’s to relax the pelvic muscles can ease the pain. The use of stool softeners is also common. Many will use some kind of cushion (donut) while sitting. Iced or hot packs have been used for the same purpose to decrease the inflammation and hopefully eliminate pain. They will take some time off work and be comfortable at home.

Once seen in the office, more options become available like physical therapy and sit baths. Coccygeal nerve blocking can be offered using steroid medications to supplement the anti-inflammatory medications like the Cox-2 inhibitors or other medications. Coccygeal massages and stretching exercises for the Levator ani and other pelvic muscles may relieve the symptoms. 

A short video where I am performing an injection of the Sacro-Coccygeal joint and hopefully the lector will be able to appreciate it. In spite of the local anesthesia, it can be a little uncomfortable. Please, click on the icon to play the video: