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 in 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).
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 together 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. Nerves of the coccyx include somatic nerve fibers as well as 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.
Direct vertical trauma, repetitive microtrauma, and childbirth are common causes of coccyx pain. However, more serious underlying causes must be excluded, such as infections (including both soft tissue abscess and osteomyelitis) or malignancy (including chordoma, which has a high fatality rate).
Also, coccydynia can be a referred pain due to lower gastrointestinal or urogenital disorders. Neurological causes such as lumbar disc prolapse have been reported as a possible etiology in a limited number of cases.
The outcome of direct vertical trauma to the coccyx can vary from contusion to fracture-dislocation of the coccyx. Traumatic or non-traumatic compromise of the coccygeal ligaments can result in coccygeal dynamic instability (excessive movement of the coccyx during weight-bearing, while sitting). Abnormal mobility of the coccyx can result in coccygeal pain. Abnormally mobile coccyges can be either hypermobile (due to lax ligaments) or hypomobile (rigid). The coccyx may be subluxated anteriorly or posteriorly, unstable, or even dislocated.
Coccyxes of certain shapes are more predisposed to coccydynia than others. Abnormal coccygeal morphology or position predisposing to coccyx pain include abnormal scoliotic deformity (lateral deviation) or a coccyx that is excessively flexed or excessively extended.
A distal coccyx bone spur (spicule) may cause pain when the skin is pinched beneath the spur during sitting.
Idiopathic coccydynia is a 'diagnosis of exclusion' after careful screening for identifiable causes.
Factors related to the high risk of developing coccydynia are female sex and obesity as body mass index may affect the way a person sits or the amount of weight placed upon the coccyx. Coccydynia is five times more common in females than in males. Rapid weight loss has been reported to be a risk factor for coccydynia due to the loss of the cushioning effect of adipose at the buttock region. Other reported risk factors include osteoarthritis, osteomyelitis, and contact sports.
The typical presentation of coccydynia is pain localized to the coccyx. In traumatic coccydynia, there will be a preceding history of trauma followed by acute onset of pain. In idiopathic coccydynia, the pain will often have an insidious onset without any obvious or specific precipitant. In coccydynia, due to other causes, a careful and thorough history will often suggest the possible etiology.
Coccydynia is typically worse while sitting and especially while sitting in a partly reclined (backward leaning) position. The pain is usually exacerbated by prolonged sitting and cycling. Standing up from the seated position may cause a temporary but severe increase in coccyx pain. Other exacerbating factors may include standing for a long time, sexual intercourse, and defecation.
Physical examination includes inspection of the overlying skin for any signs suggestive of infection or other differential diagnoses such as pilonidal sinus and hemorrhoids.
"Foye's finger" for coccydynia: This is comparable to "Fortin's finger," where Dr. Fortin published on the usefulness of having patients with sacroiliac joint pain point to their site of pain, thus helping to distinguish this from lumbar pain generators. Similarly, Dr. Foye recommends asking patients to point with one finger to their worst site of pain, which in coccydynia patients will be far more inferior than the more common causes of low back pain (located up in the lumbosacral spine), and more midline than buttock pain syndromes (such as sacroiliac pain and piriformis pain).
External palpation usually reveals localized tenderness focally over the coccyx.
Per rectal examination may be useful in some patients to evaluate the degree of coccygeal mobility and will typically elicit pain when manipulating the coccyx.
Beyond the evaluation of the coccyx itself, it is often helpful to also assess for other sources of musculoskeletal pain by performing a physical examination of the sacroiliac joints, ischial bursae, and piriformis muscles.
Standard radiographs: AP radiographs can reveal coccyx scoliotic (lateral deviation) deformity. Lateral views are always indicated as coccyx curvature can be classified into four different types:
From the lateral radiographs, the examiner can assess the intercoccygeal angle, which is the measured angle between the first and last segment of the coccyx, as proposed by Drs. Kim and Suk. It is used to assess the anterior angulation deformity of the coccyx. An increased intercoccygeal angle (increased forward angulation) has been reported as a possible etiology of coccydynia.
Dynamic radiographs (sitting and standing): Dr. Maigne, in France, invented the idea of seated X-rays of the coccyx as a way to see the coccyx position while the coccydynia patient was most symptomatic, which typically occurs while sitting. By comparing the coccyx position while sitting versus the position while standing, the clinician can objectively measure the amount of change. These coccygeal movements are measured as changes in the coccygeal angle (amount of flexion) and luxation (amount of listhesis at each of the coccygeal joints). These studies allow the classification of patients with coccydynia into groups based on coccygeal luxation and mobility (hypomobile, hypermobile, and normal mobility). The normal range of coccygeal mobility is between 5 and 20 degrees. Thus, if sitting causes a change in the coccygeal angle of fewer than 5 degrees, then this is hypomobility. Conversely, if sitting changes the coccygeal angle by 20 degrees or more, then this is hypermobility.
The patients responding best to manual treatments are those with normal coccyx mobility, while those with immobile coccyxes had poor results with manual treatments. In people without coccydynia, the change in luxation (listhesis) at the coccygeal joints is less than 25% of the anterior-posterior depth of the coccygeal vertebral body. Seated radiographs of the coccyx often reveal abnormalities that were missed on non-seated radiographs.
Computed tomography scan (CT) of a normal adult coccyx shows variability in the fusion of the sacrococcygeal and intercoccygeal joints. Female coccyges are more often shorter, straighter, and more retroverted.. However, these anatomic findings should be interpreted in correlation with a thorough history and detailed clinical examination before determining whether the findings are (or are not) the cause of the patient's pain.
Magnetic resonance imaging (MRI) can be used to assess anterior curvature of the coccyx, the fusion of the sacrococcygeal and intercoccygeal joints, as well as the presence of a distal coccyx bone spicule (spur). These anatomical findings can either be a precipitant or a consequence of coccydynia. Overall, MRI can be a very helpful diagnostic test for patients with coccydynia. MRI can also assist in screening for local malignant and non-malignant tumors.
Coccygeal discogram: This involves injecting contrast and local anesthetic into the sacrococcygeal region in an attempt to determine the specific site of pain. It can serve as a diagnostic and therapeutic procedure.
Nuclear medicine bone scan: This is typically only used in patients with coccydynia in whom a search for malignancy or infection (e.g., osteomyelitis) is warranted.
Routine blood tests: These studies may help in rare cases, such as when suspected etiologies include infection, malignancy, gastrointestinal or urogenital problems.
Many patients with coccydynia experience relief of symptoms within weeks or months of onset, whether they receive medical treatment or not. The success of conservative treatment has been reported to be 90%. The following modalities can be offered in acute and chronic cases:
Chronic and Refractory Coccydynia
The following conditions can result in pain in the coccyx region that should be differentiated from coccydynia:
The prognosis for patients with coccydynia is variable. While most patients' symptoms improve or resolve with conservative (non-surgical) care, other patients have coccyx pain that is notoriously persistent, even lifelong. The severity of the pain and the functional impairment (the limited ability for sitting) can be disabling. Coccygectomy has a relatively high rate of postoperative infection, and even after tailbone removal, many patients have some degree of persistent pain.
One complication of coccydynia is that it may become a chronic pain syndrome. Early and thorough medical attention may help patients to avoid delays in diagnosis and treatment. The hope is that this will help decrease the chances of the pain becoming persistent and disabling.
Referral to a specialist with expertise in treating coccydynia is warranted if the initial treating clinician is not knowledgeable about this condition, or is unable to provide the patient with a specific and accurate anatomic diagnosis, or is unable to provide the patient with adequate relief.
If tailbone pain is severe or if it persists for more than one month, then the patient should see a clinician with experience in the evaluation and treatment of this condition. If the first clinician a patient sees for coccyx pain is not familiar with this condition or does not take the patient's symptoms seriously, the patient should seek further medical care elsewhere.
Many patients have difficulty finding a radiology center that is familiar with performing the sitting-versus-standing x-rays of the coccyx, which are done to view the coccyx during the time when it is most painful (which is typically while sitting). Continuing to search for such a center is important, as these x-ray radiographs can often reveal an abnormality (diagnosis) that non-seated x-rays fail to show.
An interprofessional team approach yields the highest chance of success in treating cases of refractory coccydynia. This team can include primary clinicians, orthopedic surgeons, physiatrists, sports medicine clinicians, nurses, pharmacists, physical therapists, and psychotherapists. Improvement of patient outcomes can be achieved by making rational use of medications, injections, pelvic floor physical therapy, surgery, and psychotherapy.
|||Foye PM, Coccydynia: Tailbone Pain. Physical medicine and rehabilitation clinics of North America. 2017 Aug [PubMed PMID: 28676363]|
|||Foye PM, Stigma against patients with coccyx pain. Pain medicine (Malden, Mass.). 2010 Dec [PubMed PMID: 21134124]|
|||Sugar O, Coccyx. The bone named for a bird. Spine. 1995 Feb 1; [PubMed PMID: 7732478]|
|||Woon JT,Stringer MD, Clinical anatomy of the coccyx: A systematic review. Clinical anatomy (New York, N.Y.). 2012 Mar; [PubMed PMID: 21739475]|
|||Lirette LS,Chaiban G,Tolba R,Eissa H, Coccydynia: an overview of the anatomy, etiology, and treatment of coccyx pain. The Ochsner journal. 2014 Spring; [PubMed PMID: 24688338]|
|||Kerr EE,Benson D,Schrot RJ, Coccygectomy for chronic refractory coccygodynia: clinical case series and literature review. Journal of neurosurgery. Spine. 2011 May; [PubMed PMID: 21332277]|
|||Patijn J,Janssen M,Hayek S,Mekhail N,Van Zundert J,van Kleef M, 14. Coccygodynia. Pain practice : the official journal of World Institute of Pain. 2010 Nov-Dec; [PubMed PMID: 20825565]|
|||Kim NH,Suk KS, Clinical and radiological differences between traumatic and idiopathic coccygodynia. Yonsei medical journal. 1999 Jun; [PubMed PMID: 10412331]|
|||Postacchini F,Massobrio M, Idiopathic coccygodynia. Analysis of fifty-one operative cases and a radiographic study of the normal coccyx. The Journal of bone and joint surgery. American volume. 1983 Oct; [PubMed PMID: 6226668]|
|||Doursounian L,Maigne JY,Jacquot F, Coccygectomy for coccygeal spicule: a study of 33 cases. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2015 May [PubMed PMID: 25559295]|
|||Maigne JY,Doursounian L,Chatellier G, Causes and mechanisms of common coccydynia: role of body mass index and coccygeal trauma. Spine. 2000 Dec 1; [PubMed PMID: 11145819]|
|||Nathan ST,Fisher BE,Roberts CS, Coccydynia: a review of pathoanatomy, aetiology, treatment and outcome. The Journal of bone and joint surgery. British volume. 2010 Dec; [PubMed PMID: 21119164]|
|||[PubMed PMID: 9247654]|
|||[PubMed PMID: 8009351]|
|||[PubMed PMID: 22354690]|
|||Maigne JY,Chatellier G, Comparison of three manual coccydynia treatments: a pilot study. Spine. 2001 Oct 15; [PubMed PMID: 11598528]|
|||Maigne JY,Tamalet B, Standardized radiologic protocol for the study of common coccygodynia and characteristics of the lesions observed in the sitting position. Clinical elements differentiating luxation, hypermobility, and normal mobility. Spine. 1996 Nov 15 [PubMed PMID: 8961446]|
|||Foye PM,Kumbar S,Koon C, Improving Coccyx Radiographs in Emergency Departments. AJR. American journal of roentgenology. 2016 Oct [PubMed PMID: 27383137]|
|||Woon JT,Perumal V,Maigne JY,Stringer MD, CT morphology and morphometry of the normal adult coccyx. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2013 Apr; [PubMed PMID: 23192732]|
|||Foye PM,Kumar S, Letter to the editor concerning [PubMed PMID: 24292276]|
|||Woon JT,Maigne JY,Perumal V,Stringer MD, Magnetic resonance imaging morphology and morphometry of the coccyx in coccydynia. Spine. 2013 Nov 1; [PubMed PMID: 23917643]|
|||Foye PM,Desai RD, MRI, CT scan, and dynamic radiographs for coccydynia: comment on the article "role for magnetic resonance imaging in coccydynia with sacrococcygeal dislocation", by Trouvin et al., Joint Bone Spine 2013;80:214-16. Joint bone spine. 2014 May [PubMed PMID: 24462128]|
|||Mitra R,Cheung L,Perry P, Efficacy of fluoroscopically guided steroid injections in the management of coccydynia. Pain physician. 2007 Nov; [PubMed PMID: 17987101]|
|||Foye PM,Buttaci CJ,Stitik TP,Yonclas PP, Successful injection for coccyx pain. American journal of physical medicine [PubMed PMID: 16924191]|
|||[PubMed PMID: 17543827]|
|||[PubMed PMID: 17987103]|
|||[PubMed PMID: 19500274]|
|||Plancarte R,González-Ortiz JC,Guajardo-Rosas J,Lee A, Ultrasonographic-assisted ganglion impar neurolysis. Anesthesia and analgesia. 2009 Jun [PubMed PMID: 19448244]|
|||Scott KM,Fisher LW,Bernstein IH,Bradley MH, The Treatment of Chronic Coccydynia and Postcoccygectomy Pain With Pelvic Floor Physical Therapy. PM & R : the journal of injury, function, and rehabilitation. 2017 Apr [PubMed PMID: 27565640]|
|||Pennekamp PH,Kraft CN,Stütz A,Wallny T,Schmitt O,Diedrich O, Coccygectomy for coccygodynia: does pathogenesis matter? The Journal of trauma. 2005 Dec; [PubMed PMID: 16394915]|
|||Perkins R,Schofferman J,Reynolds J, Coccygectomy for severe refractory sacrococcygeal joint pain. Journal of spinal disorders [PubMed PMID: 12571492]|
|||Wray CC,Easom S,Hoskinson J, Coccydynia. Aetiology and treatment. The Journal of bone and joint surgery. British volume. 1991 Mar [PubMed PMID: 2005168]|