Tendinitis is an acutely inflamed swollen tendon that doesn’t have microscopic tendon damage. The underlying culprit in tendinitis is inflammation. Although tendinitis can be caused by a sudden injury, the condition is much more likely to stem from the repetition of a particular movement over time. Most people develop tendinitis because their jobs or hobbies involve repetitive motions, which put stress on the tendons. Using smartphones to surf the web is a common example in this day and age and common in kids!

Other common names for tendonitis are:

  • Shoulder tendonitis
  • Achilles tendonitis
  • Lateral Epicondylitis (Tennis Elbow)
  • Medial Epicondylitis (Golfers Elbow)
  • Patellar Tendonitis
  • Stenosing Tenosynovitis (De Quervain’s Disease of the thumb)

Tendinosis

Tendinosis is a chronically damaged tendon with disorganized fibers and a hard, thickened, scarred and rubbery appearance.

https://www.webmd.com/fitness-exercise/arthritis-tendinitis#1