Pain on the ulnar side of the wrist — the outer wrist on the little-finger side — is one of the most common wrist complaints. So many different structures pack into a small area and produce overlapping symptoms. Getting to the right diagnosis takes a thorough assessment. So what causes ulnar-sided wrist pain, how is it assessed, and how is it treated? 

The key structures on the ulnar side of the wrist

Distal radioulnar joint (DRUJ) — where the ulna meets the radius; it lets you rotate your forearm (palm up and palm down)

Triangular fibrocartilage complex (TFCC) — a cartilage-and-ligament “cushion and hammock” at the end of the ulna that stabilises the DRUJ and takes load across the ulnar wrist; the most common source of ulnar wrist pain.

Lunotriquetral (LT) ligament — one of the small ligaments linking the carpal bones

Extensor carpi ulnaris (ECU) and flexor carpi ulnaris (FCU) tendons — the two tendons running along the ulnar wrist

Pisotriquetral joint — a small joint at the base of the palm on the ulnar side

Ulnar nerve and artery — running through a tunnel (Guyon’s canal) on the ulnar side

picture of ulnar wrist anatomy

How ulnar-sided wrist pain is assessed

Because so many areas overlap, we assess step by step. A useful way for doctors to organise it is a “three-story” model, using the bony bump of the ulnar styloid as the central landmark and asking you to point to the single most painful spot with one finger. That location, more than anything, narrows the diagnosis.

Start with the history.

Generally, the history often points the way: your age and hand dominance; your job and sport (gymnasts, racquet and bat sports); whether the pain came on suddenly (a fall onto an outstretched hand, or a forced twist) or gradually (overuse); and what makes it worse. It also matters whether the main problem is pain, or pain with instability, clicking, or clunking.

Then examine by region.

We usually focus the examination on the ulnar (outer)  wrist. The most useful of these include:

  • The ulnar fovea sign — pressing the soft spot between the ulnar styloid and the FCU tendon; tenderness here is the most reliable clinical sign of a TFCC (foveal) or ulnotriquetral problem
  • The DRUJ ballottement and “piano-key” tests — checking the stability of the joint between the radius and ulna
  • The ulnocarpal stress (grind) test — loading and rotating the ulnar-deviated wrist to reproduce pain from a TFCC tear or ulnocarpal impaction
  • The ECU synergy test — a simple test that points to the ECU tendon as the source
  • The lunotriquetral ballottement/shear tests — for instability between those two carpal bones

The right imaging for outer wrist pain

Usually, we confirm the diagnosis with the following imaging: 

  • X-rays — the first-line test, and important for ulnar variance (whether the ulna sits long or short relative to the radius)
  • Ultrasound — excellent for the tendons and soft tissues. It’s also used to guide injections. 
  • MRI (and MR arthrography) — the best test for the TFCC and the small ligaments; a stronger (3-tesla) magnet
  • Wrist arthroscopy — keyhole surgery, considered the gold standard for confirming and treating a TFCC or ligament tear

The differentials: what causes outer wrist pain?

It helps to group the causes by how common they are.

Common causes

TFCC tear (the most common)

The triangular fibrocartilage complex can tear from injury (a fall onto an outstretched hand or a forced twist) or gradual wear. It’s the most common cause of ulnar wrist pain and typically causes pain and tenderness in the fovea, clicking, and pain with gripping and rotation. Traumatic tears at the well-supplied edge of the TFCC can heal or be repaired; central (worn) tears have a poor blood supply and are usually managed differently. See our guide to a wrist cartilage (TFCC) tear.

DRUJ instability or arthritis. Problems at the joint between the radius and ulna can cause pain with forearm rotation, sometimes with a sense of the joint slipping, or arthritis causing pain, crepitus, and stiffness. See our guide on DRUJ pain. 

Ulnocarpal impaction syndrome. When the ulna is slightly long (positive ulnar variance), it repeatedly bumps against the small carpal bones, wearing down the cartilage and the TFCC. It causes pain with gripping and ulnar deviation and is a common cause of chronic ulnar wrist pain.

ECU tendonitis. The extensor carpi ulnaris tendon is a frequent source of pain on the back of the ulnar wrist, from overuse or from the tendon snapping out of its sheath. See our guide to ECU tendonitis.

Less common causes

  • Lunotriquetral instability — a tear of the ligament between the lunate and triquetrum, causing focal tenderness and sometimes a click
  • Flexor carpi ulnaris (FCU) tendonitis — pain on the palm side, felt a few centimetres above the pisiform.
  • Pisotriquetral arthritis — arthritis of the small pisiform joint, aggravated by direct pressure and wrist flexion (common in racquet sports)
  • Midcarpal instability — a clunking wrist as it moves from side to side

Rarer causes not to miss

  • Ulnar styloid impaction (linked to a particular carpal-bone shape)
  • Kienböck’s disease — loss of blood supply to the lunate bone (a form of osteonecrosis) in young people 
  • Nerve and vascular causes — compression of the ulnar nerve in Guyon’s canal (numbness and weakness in the ring and little fingers), or ulnar artery problems from repetitive impact against the heel of the hand (hypothenar hammer syndrome, seen in manual workers)

How is ulnar-sided wrist pain treated?

In most cases, we start with simple treatments.

  • Activity modification — reducing the loading, gripping, and forearm rotation that aggravate it
  • Splinting or bracing — resting the wrist (and, for some tendon problems, a specific position) to settle symptoms
  • Physiotherapy — restoring movement, grip, and the muscle control that stabilises the wrist
  • An ultrasound-guided injection — a targeted corticosteroid injection can settle a tendon problem (such as ECU tendonitis) or an arthritic joint (such as the DRUJ or pisotriquetral joint). An injection of local anaesthetic can also help confirm exactly where the pain is coming from

When surgery is considered for outer wrist pain

Generally, we reserve surgery for problems that don’t settle or won’t respond to simple care—for example, a repairable TFCC tear with DRUJ instability, an ulnocarpal impaction needing the ulna shortened, or an unstable ligament tear. Hand surgeons treat these with keyhole surgery. 

Where does a sports medicine doctor fit in?

Ulnar-sided wrist pain sits right at the meeting point of sports medicine and hand surgery. As sports doctors, we add value in three ways:

  • a specific diagnosis;
  • ultrasound in clinic, which is good at diagnosing dynamic tendon problems and at guiding injections;
  • treating the many causes that respond to physio and a targeted injection—while recognising the smaller number that need a hand surgeon. 

Frequently asked questions about outer wrist pain

What is the most common cause of ulnar-sided wrist pain?

A tear of the triangular fibrocartilage complex (TFCC) — the cartilage-and-ligament cushion at the end of the ulna — is the most common cause. It can follow an injury, such as a fall onto an outstretched hand or a forced twist, or it can develop gradually with wear. But several other conditions cause very similar symptoms.

Why is ulnar-sided wrist pain so hard to diagnose?

Because many small structures are packed into a small area, they produce overlapping symptoms. This is why it’s sometimes called a diagnostic “black box.” The way through it is region-by-region assessment that pinpoints the single most tender spot and uses specific tests and imaging. 

How do I know if I’ve torn my TFCC?

The typical picture is pain on the little-finger side of the wrist, tenderness in the “fovea” (the soft spot just beyond the end of the ulna), clicking, and pain that worsens with gripping and forearm rotation—a clinical examination — including the ulnar fovea sign and the ulnocarpal stress test — points to it. An MRI or wrist arthroscopy can confirm it. Only a proper assessment can distinguish a TFCC tear from the other causes.

Does ulnar-sided wrist pain need surgery?

Usually not. Most causes — a TFCC tear, ECU tendonitis, an irritated or mildly arthritic joint, early ulnocarpal impaction — settle with physiotherapy, and sometimes an ultrasound-guided injection. Surgery is reserved for tears that don’t heal, unstable joints, certain fractures, or an ulna that needs shortening. 

When should I see a doctor about wrist pain on the little-finger side?

It’s worth being assessed if the pain is persistent, follows a significant fall or twist, comes with clicking, clunking, or a sense of instability, or is accompanied by numbness or tingling in the ring and little fingers. Because some causes are easily missed on X-rays, ulnar wrist pain that isn’t settling deserves a proper assessment, not just being pushed through.

Final word from Sport Doctor London about ulnar-sided wrist pain

Ulnar-sided wrist pain is common, and genuinely difficult to diagnose, because so many structures overlap in a small space. The answer is a region-based assessment. Not all ulnar-sided wrist pain is a TFCC tear. Most causes respond well to conservative treatment and a targeted, ultrasound-guided injection, with surgery reserved for the minority that need it.

If you have persistent pain on the little-finger side of your wrist, Dr Masci can assess you in London, including ultrasound in clinic, and arrange the right imaging or onward referral. Contact the team here or call +44 (0) 203 488 0350.

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