Wrist Tendonitis: Intersection Syndrome, ECU Tendonitis & Other Common Causes of Wrist Pain

Wrist pain has many causes, and tendonitis is one of the most common. While De Quervain’s tendonitis (which I cover in a separate blog post) gets the most attention, several other wrist tendon conditions cause significant pain and are frequently misdiagnosed or undertreated.

Intersection Syndrome 

Intersection syndrome causes pain and swelling on the back of the forearm, about 2–3 inches above the wrist. It occurs where two groups of tendons cross over each other (the first and second dorsal compartment muscles). Repetitive wrist extension and flexion— common in rowing, weightlifting, skiing, and racquet sports—causes friction and inflammation at this crossing point. Symptoms include pain, swelling, and sometimes a squeaking sensation (crepitus) with wrist movement at the dorsal forearm proximal to the wrist. Treatment includes splinting, activity modification, anti-inflammatory medications, and corticosteroid injection. Surgery is rarely needed but can address the crossing point if conservative treatment fails.

ECU Tendonitis and Subluxation

The extensor carpi ulnaris (ECU) tendon runs along the ulnar (pinky) side of the wrist. ECU tendonitis causes pain at the dorsal-ulnar wrist, worsened by wrist extension and ulnar deviation. It’s common in golfers, tennis players, and anyone who performs repetitive twisting motions. ECU subluxation is a related condition where the tendon snaps out of its groove during forearm rotation, causing a painful clicking or popping on the ulnar side of the wrist. In some cases, the tendon’s retaining sheath (subsheath) needs surgical reconstruction.

Extensor Tendonitis (Other Compartments)

The wrist has six dorsal compartments, each containing extensor tendons. Tendonitis can develop in any compartment due to overuse, repetitive motions, or inflammatory conditions. The location of pain on the back of the wrist helps identify which compartment is involved, guiding targeted treatment.

Flexor Carpi Radialis (FCR) Tendonitis

FCR tendonitis causes pain at the volar-radial wrist (palm side, thumb side)—near where you’d feel for a pulse. It can be confused with CMC arthritis or scaphoid pathology. Tenderness directly over the FCR tendon and pain with resisted wrist flexion help make the diagnosis.

General Treatment Principles

For most wrist tendonitis conditions, I follow a stepwise approach: • Activity modification and ergonomic adjustments • Wrist splinting to rest the affected tendon • Anti-inflammatory medications (oral or topical) • Corticosteroid injection—targeted to the specific compartment or tendon sheath • Physical therapy for stretching, strengthening, and ergonomic training • Surgery is reserved for cases that fail comprehensive conservative treatment

Frequently Asked Questions

How do I know which type of wrist tendonitis I have? The location of your pain is the most important clue. A hand surgeon can pinpoint the affected tendon through physical examination and, if needed, diagnostic imaging or injection. Is wrist tendonitis the same as carpal tunnel? No. Tendonitis causes wrist pain and tenderness. Carpal tunnel syndrome causes numbness and tingling in the fingers from nerve compression. They are different conditions, though both can coexist.

Wrist Pain Evaluation in Phoenix

If you’re dealing with wrist pain that’s not getting better, getting the right diagnosis is the first step. I evaluate and treat all types of wrist tendonitis for patients across Phoenix, Scottsdale, Mesa, Chandler, Gilbert, and the entire Valley.

☎ Schedule Your Consultation

Call (602) 258-4788 or visit toddrichardsmd.com to book an appointment with Dr. Todd Richards. Most insurance plans accepted. Same-week appointments often available.