Do I Need an MRI After Falling on My Tailbone and Having Coccyx Pain?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: June 28, 2025Updated: June 28, 2025

Summary

Most people who bruise or sprain the tailbone improve within 4–6 weeks and never need an MRI. You should consider MRI only if pain lasts more than six weeks, is getting worse, or you have red-flag symptoms like new leg weakness, loss of bowel or bladder control, fever, or known cancer. An MRI shows soft-tissue injuries and occult fractures that plain X-rays can miss.

Do I really need an MRI after falling on my tailbone?

MRI is rarely the first test for a coccyx injury. Doctors usually start with a focused physical exam and, if imaging is needed, a plain X-ray while you sit and stand. MRI becomes relevant only when pain lingers or serious complications are suspected.

  • MRI is reserved for chronic or complicated casesGuidelines suggest waiting at least 6 weeks before ordering MRI unless red-flag symptoms are present.
  • Soft-tissue detail is the MRI advantageMRI can reveal a hidden pilonidal abscess, ligament tear, or a fracture line that an X-ray misses.
  • Insurance often requires step-wise imagingMany insurers deny coccyx MRI unless an X-ray or CT was performed first.
  • Expert insight“For an uncomplicated fall, conservative care comes first; MRI is your safety net, not your starting point,” says Sina Hartung, MMSC-BMI.
  • A standard lumbar MRI skips the actual tailboneBecause conventional lumbar protocols stop above the sacrum, you must request a “sacrum-coccyx” or “pelvic MRI with attention to the coccyx” if you want images of the tailbone. (TailboneDoctor)
  • MRI can uncover injuries missed for years on normal X-raysIn a published case, a patient with three years of coccydynia and normal sitting-standing radiographs was finally diagnosed by MRI/CT with a mobile coccygeal fragment that required surgery. (PMC)

References

Which coccyx injury signs mean I should see a doctor today?

Certain symptoms suggest a fracture extending to the sacrum, infection, or nerve involvement. Immediate medical review is warranted.

  • Loss of bowel or bladder controlNew incontinence can indicate compression of sacral nerves and requires urgent MRI.
  • Progressive leg weakness or numbnessIn a 2023 registry, 3 % of tailbone injuries with leg symptoms had an underlying sacral fracture.
  • Fever over 100.4 °F with tailbone painMay signal osteomyelitis; blood cultures and MRI with contrast are standard work-up.
  • Severe pain despite high-dose analgesiaIf pain scores stay above 8/10 after 48 hours, imaging is justified, according to the team at Eureka Health: “Escalating pain, not just duration, pushes us toward advanced imaging.”
  • Visible hard lump or tailbone protrusionA noticeable bump or misalignment after a fall can signal coccyx dislocation or fracture and should be assessed with prompt imaging. (Healthline)
  • Swelling or bruising that remains intense beyond several daysNJ Spine & Orthopedic recommends an early X-ray when marked tenderness and bruising persist, as these symptoms raise suspicion for a broken tailbone. (NJSpine)

References

How do doctors decide between X-ray, CT, and MRI for tailbone pain?

Each test answers a different clinical question. The decision depends on injury age, suspected tissue type involved, and prior imaging.

  • Plain X-ray for alignment and dislocationDynamic sitting-standing coccygeal X-rays detect abnormal angulation in 64 % of symptomatic patients.
  • CT for complex bony anatomyCT slices the coccyx into 0.5 mm sections, uncovering small avulsion fractures missed on X-ray.
  • MRI for soft-tissue and marrow edemaBone bruises light up on STIR sequences within 72 hours.
  • Cost and radiation influence choicesMRI costs roughly 3–4× more than X-ray but eliminates ionizing radiation.
  • Specialist quote“We escalate from X-ray to CT or MRI only when the findings will change treatment,” notes the team at Eureka Health.
  • Coccydynia represents a small but significant slice of back pain visitsThe RSNA review notes that coccydynia accounts for 2.7 % of back-pain presentations and produced more than 14,000 U.S. emergency-department visits in 2014, underscoring the need for targeted imaging choices. (RSNA)
  • Initial sit–stand radiographs are recommended before cross-sectional imagingMedscape’s work-up algorithm advises starting with dynamic lateral X-rays, reserving CT or MRI for persistent pain, equivocal films, or suspected tumor or infection. (Medscape)

References

What can I do at home today to ease tailbone pain from a fall?

Most coccyx bruises heal with simple measures. The goal is to reduce pressure, inflammation, and muscle spasm.

  • Use a U-shaped or donut cushionCushioning reduces coccygeal pressure by up to 70 % in force-plate studies.
  • Alternate ice and gentle heatApply an ice pack 15 minutes every 2 hours for the first 48 hours, then switch to warm compresses to relax pelvic muscles.
  • Try leaning forward when sittingTilting shows a 30 % drop in pain scores in ergonomic trials.
  • Stretch the pelvic floor twice dailySimple cat-camel movements improve coccygeal mobility and circulation.
  • Expert encouragement“Small posture tweaks often shave weeks off recovery,” says Sina Hartung, MMSC-BMI.
  • Prevent constipation to take pressure off your coccyxA high-fiber diet, plenty of fluids, and daily walking limit straining; Kaiser notes these steps can keep bowel movements soft so they don’t aggravate the injured tailbone. (Kaiser)
  • Short courses of NSAIDs resolve most coccydynia casesNon-steroidal anti-inflammatory drugs, used with simple home care, lead to improvement in about 90 % of patients, meaning surgery is rarely needed. (PrecisionPain)

References

Which tests, prescriptions, or injections might be ordered for persistent coccyx pain?

When pain lasts longer than two months, clinicians start looking for reversible causes and targeted treatments.

  • Inflammatory markers guide infection work-upESR >40 mm/h or CRP >10 mg/L raises suspicion for osteomyelitis and prompts MRI with gadolinium.
  • Image-guided steroid injectionFluoroscopic coccygeal injections provide ≥50 % pain relief in 60–75 % of chronic cases.
  • Short trial of neuropathic pain medicationLow-dose agents such as a tricyclic at night can dampen nerve pain; dosing is individualized by your clinician.
  • Consider ganglion impar blockThis targeted nerve block has a 70 % success rate at 3 months for refractory coccydynia.
  • Eureka Health perspective“We reserve surgery for less than 1 % of patients; most respond to injections plus pelvic-floor therapy,” the team at Eureka Health explains.
  • Dynamic sit–stand X-rays spot coccygeal instabilityDynamic lateral sacrococcygeal radiographs obtained in both sitting and standing positions can reveal hypermobility or subluxation that static films miss, making them the preferred next step when pain persists beyond two months. (BMJ)
  • Pressure-relieving cushions are a first-line prescriptionGuidelines recommend donut or wedge cushions to off-load the tailbone during prolonged sitting; many patients achieve adequate relief with this simple measure before progressing to injections or surgery. (BMJ)

References

How can Eureka’s AI doctor guide me through tailbone injury recovery?

The app translates your daily pain scores, activity levels, and any red-flag symptoms into clear next steps and suggested questions for your clinician.

  • Automated symptom trackingYou enter pain, sitting tolerance, and bowel changes; the AI trends them and flags deterioration.
  • Personalized imaging checklistIf your pain persists past 6 weeks, Eureka generates a summary you can take to your doctor outlining why MRI may now be appropriate.
  • Medication and therapy remindersThe app nudges you to follow the ice-then-heat schedule and log cushion use.
  • Quote from expert“People forget half of what a doctor tells them; the app fills that gap with day-to-day guidance,” says Sina Hartung, MMSC-BMI.

Why people with tailbone pain rate Eureka’s AI doctor so highly

Users describe feeling heard and having a clearer plan. In a recent in-app survey, people managing coccydynia scored the guidance 4.7 out of 5 for usefulness.

  • Safe space for sensitive symptomsYou can discuss bowel changes or sexual discomfort without embarrassment.
  • Human review backs every AI suggestionBoard-certified doctors at Eureka Health review imaging or prescription requests before they are finalized.
  • Actionable follow-up promptsThe AI reminds you to re-check pain levels two weeks after a steroid injection so no data is lost.
  • Effortless data sharingWith one tap, you can export a PDF timeline of pain scores and interventions to your orthopedic specialist.
  • Eureka Health statement“Our goal is not to replace your doctor but to make every appointment more productive,” states the team at Eureka Health.

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Frequently Asked Questions

How long should tailbone bruising hurt before I worry?

Most bruises peak at day three and fade by week four; pain persisting beyond six weeks warrants re-evaluation.

Can I keep cycling while my coccyx heals?

Switch to a wide, cut-out saddle and limit rides to 15 minutes until you can sit pain-free on a hard chair.

Do I need to fast before an MRI of the coccyx?

No fasting is required unless contrast is planned and you have kidney issues—your radiology center will advise.

Is a coccyx fracture visible on a standard lumbar MRI?

Often not; the tailbone sits below the usual lumbar field, so insist the entire sacrococcygeal region is scanned.

What sleeping position is best for tailbone pain?

Side-lying with a pillow between the knees keeps pressure off the coccyx and aligns the spine.

Could my tailbone pain be referred from a disc problem?

Yes, L4–S1 disc disease occasionally mimics coccygeal pain; MRI of the lumbar spine is considered if leg symptoms coexist.

Will my insurance cover a donut cushion?

Most plans classify cushions as comfort items, but a prescription noting ‘medically necessary for coccydynia’ may help.

When is coccygectomy (tailbone removal) considered?

Only after at least six months of documented non-surgical therapy and imaging that confirms persistent dislocation or spicule.

Can pregnancy aggravate an old coccyx injury?

Yes, hormonal laxity and delivery mechanics can flare prior trauma; prenatal pelvic-floor therapy is advisable.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

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