Tailbone X-ray cost in New York, NY
In New York-Newark-Jersey City, NY-NJ, 83 hospitals list a cash price for X-ray of the tailbone (sacrum and coccyx), 2 or more views: from $30.65 to $1,501.00, with a median of $111.37. The lowest listed price is at Brookdale Hospital Medical Center and 2 other hospitals — $80.72 less than the median here. Across New York, the median is $201.75 at 114 hospitals.
- The median here, $111.37, is 57% below the US median of $258.00.
- That is 1.3× Medicare's 2026 national rate for the same service ($88.91).
- New York, NY has the lowest median of 2 metro areas in New York with at least 10 hospitals pricing this code.
- 17 of 83 hospitals list a cash price equal to their full list price, with no self-pay discount.
Cash prices at 83 facilities across 57 cities for code 72220, as an outpatient — the setting a self-pay patient normally buys. Collected Nov 11, 2026; the hospital files themselves were last updated between Apr 22, 2025 and Sep 28, 2026.
Lowest$30.65Brookdale Hospital Medical Center + 2 more
Median$111.37half of hospitals charge less
Highest$1,501.00in this market
Difference49.0×highest vs lowest
Where each hospital's price falls
Each dot is one hospital's cash price on a scale from the lowest to the highest in New York-Newark-Jersey City, NY-NJ.
median
Lowest $30.65Highest $1,501.00
Hospitals, cheapest first
| Hospital | Cash price | List price | Insurers pay | Off list |
|---|---|---|---|---|
| Brookdale Hospital Medical Center lowest Brooklyn, NY · (718) 240-5966 HC COCCYX & SACRUM XRAY File of Aug 1, 2026 · source file | $30.65 | $145.93 | $30.00–$157.51 | 79% |
| Interfaith Medical Center lowest Brooklyn, NY HC COCCYX & SACRUM XRAY File of Aug 1, 2026 · source file | $30.65 | $145.93 | $30.65–$195.53 | 79% |
| Kingsbrook Jewish Medical Center lowest Brooklyn, NY HC COCCYX & SACRUM XRAY File of Aug 1, 2026 · source file | $30.65 | $145.93 | $29.11–$195.53 | 79% |
| NYU Langone – Tisch Hospital New York, NY · (212) 263-7300 HC X-RAY EXAM OF TAILBONE File of Jan 1, 2026 · source file | $47.61 | $250.56 | $23.57–$340.00 | 81% |
| NYU Langone – Orthopedic Hospital New York, NY HC X-RAY EXAM OF TAILBONE File of Jan 1, 2026 · source file | $47.61 | $250.56 | $23.57–$340.00 | 81% |
| NYU Langone Brooklyn, NY HC X-RAY EXAM OF TAILBONE File of Jan 1, 2026 · source file | $47.61 | $250.56 | $23.57–$340.00 | 81% |
| St. Catherine of Siena Medical Center Smithtown, NY · (631) 862-3000 HC DX SACRUM COCCYX MIN 2V File of Feb 19, 2026 · source file | $50.00 | $475.00 | $15.15–$475.00 | 89% |
| NYU Langone Mineola, NY HC X-RAY EXAM OF TAILBONE File of Jan 1, 2026 · source file | $52.67 | $277.20 | $23.57–$340.00 | 81% |
| NYU Langone Hospital - Suffolk Patchogue, NY · (631) 654-7100 HC X-RAY EXAM OF TAILBONE File of Jan 1, 2026 · source file | $64.60 | $340.00 | $23.57–$340.00 | 81% |
| University Hospital of Brooklyn Brooklyn, NY · (718) 270-1000 72220 - X-RAY EXAM SACRUM TAILBONE File of Apr 22, 2025 · source file | $65.00 | $65.00 | $5.00–$92.00 | — |
| Chsli St Joseph Hospital Bethpage, NY · (516) 759-6000 HC DX SACRUM COCCYX MIN 2V File of Feb 19, 2026 · source file | $72.36 | $494.00 | $15.15–$494.00 | 85% |
| Mercy Medical Center Rockville Centre, NY · (516) 705-2525 HC DX SACRUM COCCYX MIN 2V File of Feb 19, 2026 · source file | $72.36 | $475.00 | $15.15–$475.00 | 85% |
| Good Samaritan Hospital Medical Center West Islip, NY · (631) 376-3000 HC DX SACRUM COCCYX MIN 2V File of Feb 19, 2026 · source file | $72.36 | $475.00 | $15.15–$475.00 | 85% |
| St. Francis Hospital Roslyn, NY HC DX SACRUM COCCYX MIN 2V File of Feb 19, 2026 · source file | $72.36 | $475.00 | $15.15–$475.00 | 85% |
| Robert Wood Johnson University Hospital Rahway Rahway, NJ · (732) 381-4200 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $87.84 | $681.00 | $27.06–$457.63 | 87% |
| Ocean Medical Center Brick, NJ · (732) 840-2200 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $88.05 | $584.00 | $111.25–$496.40 | 85% |
| JFK University Medical Center Edison, NJ · (732) 321-7000 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $88.05 | $584.00 | $111.25–$496.40 | 85% |
| St Joseph's Hospital, Yonkers Yonkers, NY · (914) 378-7000 X-ray exam sacrum tailbone+2 more lines at this price File of Jul 13, 2026 · source file | $88.91 | — | $7.77–$350.26 | — |
| Newton Medical Center Newton, NJ · (973) 383-2121 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $96.21 | $1,149.00 | — | 92% |
| Ocean Medical Center Brick, NJ · (732) 840-2200 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $96.23 | $560.00 | $79.52–$492.80 | 83% |
| Southern Ocean Medical Center Manahawkin, NJ · (609) 597-6011 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $96.23 | $560.00 | $100.80–$511.95 | 83% |
| Englewood Health Englewood, NJ · (201) 894-3000 Radex Sacrum & Coccyx Minimum 2 Views File of Feb 2, 2026 · source file | $97.00 | $970.00 | $70.91–$776.00 | 90% |
| Riverview Medical Center Red Bank, NJ · (732) 741-2700 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.46 | $560.00 | $78.96–$492.80 | 83% |
| Jersey Shore University Medical Center Neptune City, NJ · (732) 775-5500 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.46 | $584.00 | $96.94–$584.00 | 83% |
| Bayshore Medical Center Holmdel, NJ · (732) 739-5900 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.46 | $560.00 | $91.84–$492.80 | 83% |
| Raritan Bay Medical Center Perth Amboy, NJ · (732) 324-5000 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.54 | $560.00 | $74.48–$540.96 | 83% |
| Old Bridge Medical Center Old Bridge, NJ RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.54 | $560.00 | $74.48–$540.96 | 83% |
| JFK University Medical Center Edison, NJ · (732) 321-7000 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $97.54 | $584.00 | $94.02–$542.71 | 83% |
| Trinitas Regional Medical Center Elizabeth, NJ · (908) 994-5000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $100.79 | $537.00 | $17.01–$402.68 | 81% |
| Saint Marys Hospital Passaic, NJ · (973) 365-4300 Hc X-Ray Sacrum/Coccyx 2+ Vw File of Sep 1, 2026 · source file | $102.00 | $488.50 | $51.58–$415.23 | 79% |
| Palisades Medical Center North Bergen, NJ · (201) 854-5000 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $103.69 | $560.00 | $95.76–$518.56 | 81% |
| Hackensack University Medical Center Hackensack, NJ · (551) 996-2000 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Dec 31, 2025 · source file | $103.69 | $584.00 | $105.12–$569.52 | 82% |
| Jacobi Medical Center Bronx, NY · (718) 918-5000 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| Kings County Hospital Center Brooklyn, NY · (718) 245-3901 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| South Brooklyn Health Brooklyn, NY · (718) 616-4834 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $233.83 | $1.00–$1,193.00 | 55% |
| Woodhull Medical & Mental Health Center Brooklyn, NY · (718) 963-8100 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| Bellevue Hospital Center New York, NY · (212) 561-4132 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| Lincoln Medical & Mental Health Center Bronx, NY · (718) 579-5000 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $233.83 | $1.00–$1,193.00 | 55% |
| Metropolitan Hospital Center New York, NY · (212) 423-6262 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $233.83 | $1.00–$1,193.00 | 55% |
| Queens Hospital Center Jamaica, NY · (718) 883-3000 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| Elmhurst Hospital Center Broadway Elmhurst, NY · (718) 334-1141 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $233.83 | $1.00–$1,193.00 | 55% |
| Harlem Hospital Center New York, NY · (212) 939-1000 HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $233.83 | $1.00–$1,193.00 | 55% |
| North Central Bronx Hospital Bronx, NY HC SACRUM & COCCYX MIN 2 VIEWS File of Sep 5, 2026 · source file | $104.19 | $327.50 | $1.00–$1,193.00 | 68% |
| Community Medical Center Toms River, NJ · (732) 557-8000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $111.37 | $537.00 | $27.06–$491.30 | 79% |
| Jersey City Medical Center Jersey City, NJ · (201) 915-2000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $111.58 | $537.00 | $22.02–$487.43 | 79% |
| CentraState Medical Center Freehold Township, NJ · (732) 294-7012 Xr Sacrum Coccyx 2+ Vw+1 more line at this price File of Apr 1, 2026 · source file | $112.08 | $590.00 | — | 81% |
| Hackensack Meridian Mountainside Medical Center Montclair, NJ · (973) 429-6000 X-ray of sacrum and tailbone, minimum of 2 views File of Feb 12, 2026 · source file | $113.60 | $555.45 | $58.32–$555.45 | 80% |
| Robert Wood Johnson University Hospital Somerset Somerville, NJ · (908) 685-2200 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $115.08 | $681.00 | $18.01–$622.97 | 83% |
| Newton Medical Center Newton, NJ · (973) 383-2121 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $116.20 | $1,956.00 | — | 94% |
| University Hospital Newark, NJ · (973) 972-4300 RADEX SACRUM & COCCYX MINIMUM 2 VIEWS File of Aug 13, 2026 · source file | $116.63 | $656.75 | $19.84–$623.91 | 82% |
| Overlook Medical Center Summit, NJ · (908) 522-2000 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $117.49 | $534.00 | — | 78% |
| Chilton Medical Center Pompton Plains, NJ · (973) 831-5000 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $117.49 | $846.00 | — | 86% |
| Monmouth Medical Center Long Branch, NJ · (732) 222-5200 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $117.49 | $537.00 | $27.06–$519.33 | 78% |
| Morristown Medical Center Morristown, NJ · (973) 971-5450 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $117.49 | $541.00 | — | 78% |
| Newark Beth Israel Medical Center Newark, NJ · (973) 926-7000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $124.14 | $596.00 | $17.51–$556.24 | 79% |
| Cooperman Barnabas Medical Center Livingston, NJ · (973) 322-5000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $126.29 | $596.00 | $27.06–$506.60 | 79% |
| Robert Wood Johnson University Hospital New Brunswick New Brunswick, NJ · (732) 828-3000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $127.12 | $596.00 | $27.06–$495.87 | 79% |
| Monmouth Medical Center Southern Campus Lakewood, NJ · (732) 363-1900 HC Xr Sacrum/Coccyx 2+V File of Mar 3, 2026 · source file | $127.64 | $537.00 | $27.06–$521.48 | 76% |
| Montefiore Medical Center Bronx, NY · (718) 920-4321 CHG RADEX SACRUM & COCCYX MINIMUM 2 VIEWS+1 more line at this price File of Sep 28, 2026 · source file | $134.07 | $205.00 | $7.43–$123.00 | 35% |
| Clara Maass Medical Center Belleville, NJ · (973) 450-2000 HC Xr Sacrum/Coccyx 2+V File of Mar 4, 2026 · source file | $135.45 | $681.00 | $27.06–$650.08 | 80% |
| Morristown Medical Center Morristown, NJ · (973) 971-5450 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $141.90 | $1,082.00 | — | 87% |
| Overlook Medical Center Summit, NJ · (908) 522-2000 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $141.90 | $1,068.00 | — | 87% |
| Chilton Medical Center Pompton Plains, NJ · (973) 831-5000 Xr Sacrum Coccyx 2+ Vw File of Apr 1, 2026 · source file | $141.90 | $1,754.00 | — | 92% |
| The Valley Hospital Paramus, NJ · (201) 447-8000 SACRUM AND COCCYX File of May 6, 2026 · source file | $176.40 | $294.00 | $23.89–$220.50 | 40% |
| Flushing Hospital Medical Center Flushing, NY · (718) 670-5000 X-RAY EXAM SACRUM TAILBONE File of Mar 25, 2026 · source file | $210.00 | $210.00 | $9.00–$1,912.00 | — |
| Jamaica Hospital Medical Center Jamaica, NY · (718) 262-6000 X-RAY EXAM SACRUM TAILBONE File of Mar 25, 2026 · source file | $210.00 | $210.00 | $16.66–$1,912.00 | — |
| St Johns Episcopal Hospital Far Rockaway, NY · (718) 869-7000 X-RAY EXAM SACRUM TAILBONE File of Apr 7, 2026 · source file | $212.87 | $250.43 | $30.00–$244.42 | 15% |
| BronxCare Hospital Center - Fulton Campus Bronx, NY · (212) 588-7000 SACRUM / COCCYX 2+ VIEWS File of May 5, 2026 · source file | $215.01 | $215.01 | $12.30–$193.51 | — |
| Bronx-Lebanon Hospital Center - Concourse Division Bronx, NY · (212) 588-7000 SACRUM / COCCYX 2+ VIEWS File of Apr 17, 2026 · source file | $215.01 | $215.01 | $12.30–$193.51 | — |
| Nassau University Medical Center East Meadow, NY · (516) 572-0123 Xray Sacrum & Coccyx 2> Vws File of Oct 28, 2025 · source file | $238.70 | $341.00 | $15.96–$625.00 | 30% |
| Montefiore Mount Vernon Hospital Mount Vernon, NY · (914) 664-8000 HC X RAY EXAM SACRUM TAILBONE File of Sep 28, 2026 · source file | $302.25 | $465.00 | $15.15–$405.19 | 35% |
| New York Community Hospital of Brooklyn Brooklyn, NY · (718) 692-5302 SACRUM AND COCCYX MIN 2 VIEWS File of Apr 1, 2026 · source file | $331.23 | $331.23 | — | — |
| New York Community Hospital of Brooklyn Brooklyn, NY · (718) 692-5302 COCCYX (SPINE) File of Apr 1, 2026 · source file | $364.37 | $364.37 | — | — |
| Maimonides Medical Center Brooklyn, NY · (718) 283-6000 SCARUM & COCCYX MIN 2 VW File of Apr 1, 2026 · source file | $385.00 | $385.00 | — | — |
| St Johns Riverside Hospital Park Care Pavillion Yonkers, NY · (914) 964-4444 X-RAY EXAM SACRUM TAILBONE File of Mar 27, 2026 · source file | $392.70 | $462.00 | $84.12–$3,783.00 | 15% |
| Mount Sinai Brooklyn Brooklyn, NY · (212) 420-2000 HC Xray Sacrum and Coccyx Min 2 View+1 more line at this price File of Apr 1, 2026 · source file | $405.00 | $450.00 | — | 10% |
| Mount Sinai Morningside New York, NY HC Myelography Cervical+1 more line at this price File of Apr 1, 2026 · source file | $405.00 | $450.00 | — | 10% |
| Mount Sinai Queens Long Island, NY HC Myelography Cervical+1 more line at this price File of Apr 1, 2026 · source file | $405.00 | $450.00 | — | 10% |
| The Mount Sinai Hospital New York, NY · (212) 241-7981 HC Myelography Cervical+1 more line at this price File of Apr 1, 2026 · source file | $405.00 | $450.00 | — | 10% |
| Hudson Regional Hospital Secaucus, NJ · (201) 392-3200 X-ray of sacrum and tailbone, minimum of 2 views File of Sep 23, 2026 · source file | $541.40 | $541.40 | $129.44–$1,021.62 | — |
| Stony Brook Southampton Hospital Southampton, NY X-RAY EXAM SACRUM TAILBONE File of Jun 17, 2026 · source file | $580.95 | $580.95 | $108.10–$140.53 | — |
| Stony Brook Southampton Hospital Southampton, NY X-RAY OF SACRUM AND TAILBONE; MINIMUM OF 2 VIEWS File of Jun 17, 2026 · source file | $639.31 | $639.31 | $108.10–$140.53 | — |
| Stony Brook University Hospital Stony Brook, NY · (631) 444-4000 X-RAY OF SACRUM AND TAILBONE; MINIMUM OF 2 VIEWS File of Jun 10, 2026 · source file | $640.00 | $640.00 | $108.10–$4,255.00 | — |
| Stony Brook University Hospital Stony Brook, NY · (631) 444-4000 X-RAY EXAM SACRUM TAILBONE File of Jun 10, 2026 · source file | $685.00 | $685.00 | $108.10–$4,255.00 | — |
| Memorial Hospital for Cancer and Allied Diseases Basking Ridge, NJ HC X-Ray Sacrum/Coccyx 2+ Vw - Xr Sacrum Coccyx 2+ Views File of Dec 1, 2025 · source file | $711.00 | $711.00 | $166.31–$1,102.00 | — |
| Memorial Hospital for Cancer and Allied Diseases Middletown, NJ HC X-Ray Sacrum/Coccyx 2+ Vw - Xr Sacrum Coccyx 2+ Views File of Dec 1, 2025 · source file | $711.00 | $711.00 | $166.31–$1,102.00 | — |
| Memorial Hospital for Cancer and Allied Diseases West Harrison, NY HC X-Ray Sacrum/Coccyx 2+ Vw - Xr Sacrum Coccyx 2+ Views File of Dec 1, 2025 · source file | $711.00 | $711.00 | $41.19–$1,198.00 | — |
| Memorial Hospital for Cancer and Allied Diseases New York, NY HC X-Ray Sacrum/Coccyx 2+ Vw - Xr Sacrum Coccyx 2+ Views File of Dec 1, 2025 · source file | $711.00 | $711.00 | $41.19–$1,198.00 | — |
| Brooklyn Hospital Center at Downtown Campus Brooklyn, NY · (718) 250-8000 X-RAY OF SACRUM AND TAILBONE; MINIMUM OF 2 VIEWS File of Jul 27, 2026 · source file | $828.16 | $828.16 | $86.48–$216.20 | — |
| Brooklyn Hospital Center at Downtown Campus Brooklyn, NY · (718) 250-8000 X-RAY EXAM SACRUM TAILBONE File of Jul 27, 2026 · source file | $948.16 | $948.16 | $86.48–$216.20 | — |
| Westchester Medical Center Valhalla, NY · (914) 493-7000 X-RAY EXAM SACRUM TAILBONE File of Jul 28, 2026 · source file | $1,099.00 | $1,099.00 | $61.72–$1,099.00 | — |
| Good Samaritan Hospital Suffern, NY · (914) 368-5000 XR Sacrum/Coccyx 2+ Views File of Jun 29, 2026 · source file | $1,488.00 | $1,488.00 | $80.14–$1,589.00 | — |
| Saint Peters University Hospital New Brunswick, NJ · (732) 745-8600 X-RAY EXAM SACRUM TAILBONE File of Nov 19, 2025 · source file | $1,501.00 | $1,533.00 | $29.00–$1,533.00 | 2% |
Hospital The hospital that published the price, its city and the line exactly as written in its price file.
Cash price The hospital's own price for a patient paying without insurance (“discounted cash” in its price file). Hospitals must publish it under federal law, 45 CFR 180.50. Call to confirm it before booking. More
List price The hospital's full chargemaster price (“gross charge”) before any discount. Almost nobody pays it; the gap to the cash price shows what the self-pay discount is worth. More
Insurers pay The lowest and highest rates this hospital has agreed with insurance plans for the same item, from its price file. If the cash price is below what your plan pays and you have not met your deductible, paying cash can cost you less. More
Off list How much lower the cash price is than the list price.
At or below Medicare This cash price is at or below what Medicare pays a hospital for the same service, which is unusually low. It is what the hospital's file says; confirm it and what it includes before booking. More
No cash discount This line's cash price equals the hospital's full list price. Many hospitals still reduce bills for uninsured patients: ask the billing office for its self-pay discount in writing. More
Outpatient: lowest $30.65, median $111.37, highest $1,501.00 — a 49.0× difference within the same market.
As an inpatient, the same code is billed by 33 facilities here, median $117.49. Inpatient and outpatient prices are not comparable and are kept on separate pages: the inpatient charge covers admission, not the same purchase.
Cash or insurance?
At 66 of 72 hospitals that publish insurer rates for this code here, the cash price is below the highest rate a health plan has negotiated, and at 4 it is below every plan's rate. If you have insurance but have not met your deductible, you usually pay your plan's negotiated rate, which falls somewhere in the "Insurers pay" column. Paying cash can cost less, but a cash payment usually does not count toward your deductible. Ask the hospital for both numbers before you book.
What tailbone X-ray is, what the price covers and why prices differ: Tailbone X-ray explained.