You try to make a fist, but one finger stays curled. Or you pull it straight with the other hand and it releases all at once with a snap felt through the palm.
When these episodes repeat, the cause may be trigger finger. Also called stenosing tenosynovitis, it affects roughly two to three people in every hundred and is several times more common in people living with diabetes.
This guide explains what trigger finger is, why it develops, how ultrasound helps diagnose it and which treatments are available.
What is trigger finger?
Each flexor tendon runs inside a sheath and is held down at intervals by bands of tissue called pulleys. The first of these, the A1 pulley, sits where the finger meets the palm.
When the tendon thickens or the pulley narrows, the tendon must pass through a space that has become too small. Straightening pulls the swollen section against the edge of the pulley, where it catches until enough force builds to pop it free.
That pop creates the characteristic trigger. The ring finger and thumb are affected most often.
What are the symptoms of trigger finger?
Symptoms often arrive one by one rather than all at once.
Tenderness or a palm lump
There may be a small firm nodule at the base of the finger. Some people find this before noticing any catching.
Morning stiffness
The finger can feel stiff first thing and loosen during the first hour.
Clicking or catching
The finger snags as it straightens and releases with an audible or palpable click.
Locking
The finger stops partway and remains there until it is helped along with the other hand.
Referred finger pain
Pain may be felt around the finger or middle knuckle even though the problem sits in the palm.
Fluctuating symptoms
Symptoms may settle for weeks and then return, which is why the condition is sometimes dismissed initially.
A dynamic ultrasound shows the trigger as it happens
A hand and wrist ultrasound examines the flexor tendon and A1 pulley while you bend and straighten the finger. No GP referral is required and same-day appointments may be available.
Hand & Wrist UltrasoundWhy does trigger finger develop?
Trigger finger develops when the tendon and pulley change in a way that prevents smooth gliding.
Age and sex are strong factors. It most often appears between the ages of 40 and 50, is considerably more common in women and usually affects the dominant hand.
Diabetes is the strongest medical association. Prevalence estimates range from 5% to 20% in people with diabetes, compared with 2% to 3% in the general population, and the condition can be more persistent.
Inflammatory arthritis, including rheumatoid arthritis, can thicken the tendon sheath and cause the same mechanical problem. Several triggering fingers, morning stiffness lasting over an hour or swelling in other joints may justify private rheumatology screening.
In other cases, repeated use of tools that press firmly into the palm may contribute.
How is trigger finger diagnosed?
Trigger finger is diagnosed clinically in most cases. An experienced clinician can often recognise it from the history and examination.
The examination includes feeling for a nodule at the base of the finger, watching the finger bend and straighten and checking whether the catching can be reproduced.
A private hand and wrist ultrasound scan adds information examination alone cannot provide: which structure is affected, how much thickening is present and whether another condition explains the symptoms.
Imaging is particularly helpful when there is swelling without obvious triggering, more than one finger is affected or an initial treatment has failed. If symptoms occur elsewhere too, consider booking a private GP appointment alongside the scan.
What does ultrasound show in trigger finger?
A hand and wrist ultrasound shows the flexor tendon, A1 pulley and tendon sheath in real time, making it the preferred imaging test for this condition.
A tendon ultrasound scan can demonstrate:
A1 pulley thickening
The narrowed pulley appears as a dark thickened band over the tendon at the base of the finger.
Tendon swelling or a nodule
The scan shows the abnormality and exactly where it sits along the flexor tendon.
Fluid in the tendon sheath
Sheath fluid can suggest an inflammatory rather than purely mechanical cause.
Increased Doppler blood flow
Extra blood flow around the tissues indicates active inflammation.
Dynamic catching
The probe remains over the pulley while the finger bends and straightens, allowing the clinician to watch the tendon snag and release.
What else could be making your finger catch?
Several conditions can cause clicking, locking or pain near the base of a finger. Distinguishing them is an important reason to scan.
| Condition | How it differs |
|---|---|
| Dupuytren’s contracture | A cord in the palm pulls the finger down. There is no click, and the finger will not straighten even with help. |
| De Quervain’s tenosynovitis | Pain is located on the thumb side of the wrist and is worse with gripping and turning. |
| Flexor tendon sheath infection | The whole finger is swollen, red, held bent and very painful. This needs urgent assessment. |
| Osteoarthritis of the finger joints | Bony swelling is centred on the knuckles, with grinding rather than a snap. |
Swipe sideways to view the complete table.
How is trigger finger treated?
Treatment usually progresses through three options: splinting, corticosteroid injection and surgical release of the A1 pulley.
Splinting
A splint holds the finger straight overnight for six to ten weeks. This reduces repeated forcing of the tendon through the narrowed pulley and gives the swelling time to settle.
Corticosteroid injection
A corticosteroid injection reduces swelling inside the sheath so the tendon can glide more freely.
A 2023 controlled study in the Journal of Orthopaedic Surgery and Research followed 66 patients. With ultrasound guidance, symptoms resolved in 82.6% of fingers within the first week, increasing to 91.3% by week two where a repeat injection was given.
An ultrasound-guided corticosteroid injection for trigger finger is available through our Joint Pain Clinic. The clinician sees the tendon, sheath and needle throughout the procedure.
Surgical release
Surgical release divides the A1 pulley to create space for the tendon. It is considered when injections have not provided lasting relief or the finger is fixed.
The procedure is usually performed under local anaesthetic. Percutaneous release succeeds in approximately 87% of cases, and the hand may be usable within days.
London Private Ultrasound does not perform trigger finger surgery. If imaging indicates release is the appropriate next step, a consultant musculoskeletal assessment can arrange specialist review with the imaging already completed.
Book a hand and wrist ultrasound at London Private Ultrasound
If a finger is catching, clicking or locking and you want a diagnosis before committing to treatment, a hand ultrasound can provide an answer in one appointment.
Experienced sonographers and clinicians
The clinician who performs the scan interprets it, supported by a team combining orthopaedic surgery, MSK ultrasound and radiology.
Static and dynamic assessment
The tendon and A1 pulley are examined at rest and while you move the finger, with the findings explained during the scan.
Treatment in the same building
Guided injections, GP consultations and specialist assessment can be coordinated through the Joint Pain Clinic.
Clear onward pathway
If an injection is indicated, it can be arranged through the clinic. If surgery is more appropriate, you can be referred onward with imaging already completed.
Convenient appointments
Same-day and next-day appointments are available seven days a week, 9am to 7pm, without a GP referral at 27 Welbeck Street in the Harley Street medical district and 54–56 Victoria Street in St Albans.
This service is for adults aged 18 and over. No GP referral is needed. Call 020 7101 3377 or contact the clinic through WhatsApp.
Book Hand & Wrist UltrasoundRelated musculoskeletal services
Hand and wrist ultrasound
Dynamic assessment of the flexor tendon, A1 pulley, tendon sheath and other accessible hand structures.
Hand & Wrist UltrasoundTendon ultrasound
Focused high-resolution assessment of tendon structure, movement, sheath fluid and active inflammation.
Tendon UltrasoundCorticosteroid injection
Ultrasound-guided injection around the affected tendon sheath when clinically appropriate.
Guided InjectionRheumatology screening
Assessment when several fingers, prolonged morning stiffness or other swollen joints suggest inflammatory disease.
Rheumatology ScreeningPrivate GP clinic
Clinical review when symptoms extend beyond the hand or a broader medical assessment is required.
Private GP ClinicCombined ultrasound and MSK consultation
Imaging combined with a musculoskeletal clinical assessment when treatment planning needs more than a scan alone.
Ultrasound & MSK ConsultationOne-Stop Orthopaedic MSK Clinic
A coordinated pathway for specialist assessment, imaging and treatment planning.
One-Stop MSK ClinicFrequently asked questions
Which doctor should you see for trigger finger?
You can see a GP, hand specialist or orthopaedic specialist, or book an imaging appointment directly. If the finger is already locking and you want the tendon assessed before choosing treatment, ultrasound provides a quick route to clarification.
Will trigger finger go away on its own?
Mild trigger finger can settle, particularly if it began after a short period of heavy hand use that has stopped. Regular locking makes spontaneous recovery less likely.
What happens if trigger finger is left untreated?
It can progress from occasional catching to locking that requires the other hand to correct. Eventually, the finger may become fixed in a bent position.
Do trigger finger splints work?
Splints help a meaningful proportion of patients, especially at earlier grades. They are generally worn at night for six to ten weeks. One trial found no significant difference at one year between splinting, injection and both treatments combined.
Why is trigger finger linked to diabetes?
Persistently high glucose can make the tissue around the tendon thicker and stiffer. Trigger finger is also more likely to require repeat treatment in people with diabetes.
Does a hand ultrasound hurt, and do I need a referral?
Hand ultrasound is painless and uses no radiation. No GP referral is required. Gel is applied and a small probe moves over the palm while you bend and straighten the finger. A written report is provided for your GP, physiotherapist or surgeon.
Is trigger finger treated on the NHS?
Yes, although local areas may apply criteria based on symptom duration and treatments already tried, and waiting times vary. A private scan can establish the diagnosis and severity before you decide which route to follow.
Can trigger finger come back after treatment?
It can return after an injection, particularly in people with diabetes. Recurrence after surgical release of the A1 pulley is uncommon.