Enthesitis and Enthesopathy Explained

A Primary Feature of Spondyloarthritis

If you have seen the words entheses, enthesitis, or enthesopathy in your X-ray or medical reports, the terminology may have been unfamiliar to you. Let's look at the meaning and also how it relates to various types of arthritis and rheumatic diseases.

  • Enthesis (plural: entheses) typically refers to the connective tissue where tendons, ligaments, or joint capsules attach to bone. Two types of entheses exist: fibrous entheses and fibrocartilaginous entheses. While that is the classic definition, a newer, broader definition suggests that enthesis is more than a simple attachment or insertion site—enthesis functions as a unit which includes adjacent tissues (for example, bone and fibrocartilage connected to synovium). The unit is referred to as the "enthesis organ complex".
  • Enthesopathy is any abnormal condition that affects the entheses (e.g., inflammation of the entheses). Enthesopathy may be due to an inflammatory condition, such as psoriatic arthritis, or a condition related to injury or overload, such as plantar fasciitis.
  • Enthesitis refers to inflammation of the entheses.
Enthesopathy on MRI
BSIP / UIG / Getty Images


Enthesitis is typically associated with pain, stiffness, and tenderness at the insertion site, sometimes without much swelling. However, where there is involvement of the large insertions of lower limbs, swelling can be significant and prominent. If swelling is absent, enthesitis can be difficult to recognize or suspect during a physical examination.

Enthesitis is common at the following sites:

  • Achilles tendon
  • Patellar tendon
  • Plantar fascia
  • Elbow epicondyles
  • Knees
  • Vertebrae
  • Iliac crest

Conditions Associated With Enthesitis

Enthesitis may be linked to inflammatory conditions or it may be mechanically induced by injury. Peripheral enthesitis is characteristic of all of the spondyloarthropathies, including undifferentiated spondyloarthritis, ankylosing spondylitis, psoriatic arthritis, enteropathic arthritis, and reactive arthritis.

Reactive arthritis is a form of arthritis that results from infection. The swelling of reactive arthritis is often triggered by infection in a more remote body part, such as the urinary tract, intestines or genitals. Typically the joints of the knees, feet, and ankles are targets for inflammation secondary to reactive arthritis. More specifically, enthesitis in people with reactive arthritis usually occurs in the plantar fascia, pelvic bones or Achilles tendon. Reactive arthritis is actually uncommon and usually goes away in most people within a year after onset.

Ankylosing spondylitis is an inflammatory condition that is most prevalent in men. The inflammation of ankylosing spondylitis affects the vertebrae and causes them to fuse. Chronic enthesitis of the tendons and ligaments of the vertebrae is the first step in the eventual fusion of vertebrae, which is the main feature of ankylosing spondylitis. People with ankylosing spondylitis can also experience enthesitis of the costochondral joints, or joints of the ribs.

Other conditions associated with enthesitis include Achilles tendinitis, rheumatoid arthritis, osteoarthritis, and diffuse idiopathic skeletal hyperostosis (DISH). It may be degenerative enthesopathy that develops with osteoarthritis. The degenerative changes that occur with wear-and-tear osteoarthritis also affect the fibrocartilages.

Imaging for Diagnosis

Imaging can help diagnose enthesitis, but the imaging modality utilized depends on whether the axial or peripheral skeleton is affected. MRI is used for the axial skeleton. Ultrasound is preferred for the peripheral skeleton. MRI would again be preferable for any insertions that are inaccessible.


Treatment of enthesitis is based on the underlying condition. For example, if enthesitis is due to an inflammatory condition, treatment usually focuses on treating the inflammatory polyarthritis. Treatment, in such cases, may include:

Depending on which areas are involved, local corticosteroid injections may be used if oral medications are inadequate. However, a healthcare provider would almost never use these injections for Achilles tendinitis or into the patella; this could lead to rupture.

The biomechanical aspects of enthesitis are also addressed by using insoles and cushions.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Creakyjoints.org. What is enthesitis? the painful arthritis symptom you should know about.

  3. Kataria RK, Brent LH. Spondyloarthropathies. Am Fam Physician. 69(12):2853-60.

  4. Sufka P. Reactive arthritis. American College of Rheumatology.

  5. Holliman K. How is a person affected?. Spondylitis Association of America.

  6.  Baraliakos X, Conaghan PG, D'Agostino MA, Maksymowych W, Naredo E, Ostergaard M, et al. Imaging in rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis, and osteoarthritis: An international viewpoint on the current knowledge and future research priorities. Eur J Rheumatol, 6(1):38-47.

  7. Aggarwal A, Sawhney S. Pediatric rheumatology: A clinical viewpoint. New York, NY: Springer Publishing.

Additional Reading

By Carol Eustice
Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis.