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Little-Finger Side Wrist Pain That Snaps When You Turn Your Palm Up
ECU tendonitis is an overloaded tendon on the back of the wrist, little-finger side, tender along a line you can trace with a fingertip. Most settle in 6 to 12 weeks with a splint, load changes and graded strengthening.
If the wrist SNAPS when you turn your palm up after an injury, the sleeve holding that tendon in its groove may be torn. Caught in the first few weeks, a cast for around 6 weeks can heal it without surgery.
Pain on the little-finger side of the wrist has two usual owners.
- One is the TFCC, the cartilage complex inside the joint.
- The other is the ECU tendon, which runs in a groove on the outside of it.
The distinction is worth making because they’re treated differently, and there’s a fairly clean way to separate them.
TFCC pain is deep, inside the joint, and worst with rotation and load. ECU pain sits on the surface, along a line you can trace with a fingertip, and it’s tender to press directly.
And if there’s a distinct snap or clunk when you turn your palm upwards, that’s the ECU tendon jumping out of its groove, which is a different problem again.
That’s the one with a clock on it. Leave a fresh snap for months and the torn sleeve stretches and scars. The cast option is gone, and the fix becomes an operation plus a few months of recovery you didn’t need to spend.
Where are you right now?
- It aches along the back of the wrist after activity, no snap. Read the tendonitis sections and the exercises.
- It snaps when you turn the palm up, and it started with an injury. Read the subluxation section, then get seen this week.
- It hurts deep inside the joint with twisting and pushing up from a chair. That’s more likely the TFCC.
What is the ECU and where does it run?
Extensor carpi ulnaris. It runs down the back of the forearm on the little-finger side, sits in a shallow groove in the end of the ulna, and attaches into the base of the little finger’s metacarpal. It cocks the wrist back and bends it towards the little finger.
Where it crosses the wrist it’s held in that groove by a fibrous sleeve of its own, separate from the usual retinaculum. That sleeve is the thing that fails in the second version of this injury. It’s also counted as part of the TFCC complex, which is why the two can be injured together.
Trace it yourself: find the knobbly bone at the back of your wrist on the little-finger side, then feel just past it towards your hand. That’s the tendon and its groove.
ECU or TFCC: how do you tell them apart?
- ECU: sore along the tendon line on the back of the wrist, tender to press on the tendon itself, worse cocking the wrist back or towards the little finger. Sometimes a visible snap.
- TFCC: deep pain inside the joint, worse pushing up from a chair, turning doorknobs, loading the hand palm-down. Tender in the soft spot just past the ulna bump, on the palm side of the tendon.
- Both: it happens, especially after a fall or a twisting injury. Clicks and clunks have their own sorting guide in wrist clicking and popping.
Not sure which tendon it is? Wrist tendonitis, tendon by tendon. Pain somewhere else in the wrist? Wrist pain by location sorts it by spot.
Version one: ECU tendonitis (tendinopathy)
Overload, not injury. An ache along the tendon line, worse after activity, tender to press, sometimes a little swollen and occasionally with mild creaking.
Common in tennis, especially in the non-dominant hand of a two-handed backhand, in golf, in rowing, and in anyone doing repetitive forceful wrist work.
Treatment follows the tendinopathy pattern: relative rest from the aggravating load, a period of splinting, then graded loading to rebuild the tendon rather than pure rest. Injection for stubborn cases, though this tendon is treated with a bit more caution than most. Realistic timeline is 6 to 12 weeks, sometimes longer.
Version two: ECU subluxation, the snapping one
This is the one people describe rather than complain about.
“It snaps.”
The sleeve holding the tendon in its groove tears, usually in a single moment: a fall with the wrist twisted, or a forceful swing where the wrist gets caught. After that, the tendon slides out of its groove during certain movements and snaps back when you reverse them.
The classic trigger is turning the palm upwards with the wrist bent towards the little finger.
You can often reproduce it deliberately, and often see the tendon move.
A wrist that aches is a tendon under load. A wrist that snaps in a repeatable way is a tendon that’s escaped from something.
(A painless snap you’ve had for as long as you can remember, on both wrists, with no injury behind it, is a different conversation. Some people’s tendons just sit loose. It’s the NEW, painful snap after an injury that’s on the clock.)
How is ECU tendonitis or subluxation diagnosed?
- Pressing along the groove. Tenderness right over the tendon, rather than in the soft spot of the TFCC.
- The ECU synergy test. Forearm turned palm up, fingers straight, you push the thumb outward against resistance. That makes the ECU fire without much wrist movement, and pain along the back of the wrist on the little-finger side points at the tendon.
- Watching it move. Turning the palm up with the wrist bent towards the little finger, to see or feel the tendon slip.
- Dynamic ultrasound watches the tendon in real time as you rotate, the best test for the snapping version.
- MRI shows tendon swelling, a torn sleeve and any TFCC damage alongside. X-ray rules out a fracture after a fall.
Which window are you in?
- The ache with no snap runs on load, not on a clock. Nothing shuts. Waiting just makes it take longer.
- OPEN: a new snap in the first few weeks after the injury. A cast holding the forearm palm-down can let the torn sleeve heal in place.
- CLOSING: weeks have passed and it still snaps every time. Get assessed now. The longer it slips, the more the sleeve stretches.
- SHUT for the cast: months of snapping. The goal changes to rebuilding the sleeve surgically. That works well. It’s just a longer road.
How long does ECU tendonitis take to heal?
The conservative version, for the ache without a snap:
- Weeks 0 to 3, calm it down: a wrist splint holding the wrist slightly cocked back, worn for the aggravating tasks and as much of the day as it needs. Stop the stroke, lift or tool that provokes it. See the wrist cock-up splint.
- Weeks 2 to 6, start loading: gentle movement and holds (below). Splint weaned to heavier tasks only.
- Weeks 6 to 12, rebuild: moving loads, then sport-specific work. Most people are back to their sport somewhere in here.
- Not clearly improving by about 3 months of doing it properly: imaging and a hand surgeon’s opinion, if that hasn’t happened yet.
Treating the snapping wrist: cast or surgery?
This one matters because the acute case and the old case get very different treatment.
Caught early, a long cast holding the forearm turned palm-down for around 6 weeks can let the torn sleeve heal, and that avoids surgery entirely. It’s an unglamorous cast in an awkward position and it’s worth it. Some surgeons use a Muenster or sugar tong splint to block the rotation instead.
- Weeks 0 to 6: cast or rotation-blocking splint, forearm palm-down. Fingers keep moving. No turning the palm up.
- Weeks 6 to 12: wrist splint for heavier tasks, movement back first, then strengthening. Turning palm-up under load comes last.
- About 3 months and beyond: graded return to racquets, clubs and the gym, often longer for heavy or high-level sport.
Left for months, the sleeve has stretched and scarred, the tendon keeps dislocating, and the fix becomes surgical reconstruction of the sleeve. That works well, and it costs you a few months of recovery you didn’t need to spend. Expect around 6 weeks of protection after it, then rehab, with full sport often 3 to 6 months out. Your surgeon’s protocol comes first.
ECU exercises
Pain during each exercise should stay mild, 3 out of 10 or less, and settle by the next morning. Once a day. If you have the snapping version, do these only once your surgeon or hand therapist has cleared you out of the cast.
- Gentle movement: wrist bend and straighten, and tipping the hand side to side, slowly and within comfort, 10 repetitions. Leave hard palm-up rotation for later.
- ECU holds: forearm resting on a table, palm down. Push the little-finger side of your hand outward against your other hand without letting it move. Hold 10 seconds, 5 to 10 times.
- Wrist extension holds: same position, push the back of the hand up into your other hand without moving. Hold 10 seconds, 5 to 10 times.
- Light loading, from about week 6: light dumbbell, palm down, lift the wrist back and lower slowly. 3 sets of 10 to 15, adding weight weekly if the next morning is quiet.
- Rotation last: hammer held near the head, palm down to palm up, 3 sets of 10, only when everything above is easy. Slide your hand down the handle to make it harder.
Can I play tennis, golf, lift or work with ECU problems?
- Tennis: the two-handed backhand and heavy topspin are the usual culprits. Drop them first. Return with shorter sessions, and get the grip size and stroke looked at. Returning to a racquet before the tendon has capacity is how these recur.
- Golf: range sessions off for now, then short-game work before full swings. Mats and divots load this tendon hard.
- Gym: neutral-grip dumbbells, wrist straight, wrist wraps. Skip palm-up curls with the wrist tipped toward the little finger, front rack and kettlebell cleans for now. See gym wrist pain.
- Manual work: screwdrivers, wrenches and heavy palm-up carrying are the worst offenders. Light duties while it settles.
- Desk work: usually fine. Keep the wrist from resting tipped toward the little finger on the mouse.
- Driving: if you can grip and turn the wheel firmly without pain catching you. The test is whether you could control the car in an emergency. Not in a long-arm cast.
What a hand therapist does differently
- Separates ECU from TFCC with a few specific tests, so you don’t spend 6 weeks treating the wrong structure.
- Spots the snapping version early and gets it to the right imaging and the right cast while the window is open.
- Molds the splint, including one that blocks rotation when the tendon needs it. Brace types side by side are in TFCC wrist braces.
- Rebuilds your specific load: the backhand, the swing, the toolbox.
Get it checked today if
- The wrist looks deformed, or the ulna head is sticking out after an injury.
- You can’t turn the forearm at all, or it feels locked.
- Numbness, or a cold or color-changed hand after the injury.
- Severe swelling and bruising after a fall. That needs an X-ray first.
- The back of the wrist is red, hot and swollen, or you have a fever.
Get it checked if
- A new, painful snap started after an injury. This week, while the cast option is still open.
- The ache isn’t clearly better after 6 weeks of changed load and a splint.
- Little-finger-side pain is still provoked by rotation or pushing at week 3.
- Your grip gives way, or the snap comes with sharp pain.
A fresh snap can heal in a cast. An old one usually needs an operation.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. A wrist that snaps after an injury is worth getting seen sooner rather than later.
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.