Pain along the radius, the larger of the two forearm bones running from your elbow to the thumb side of your wrist, usually comes from one of a handful of common causes: a fracture, nerve compression, tendon inflammation, or repetitive stress. Where exactly the pain shows up and what makes it worse are the biggest clues to what’s going on.
Where the Pain Is Matters
The radius stretches from just below your elbow to your wrist, and different problems tend to strike different zones. Pain near the wrist, at the far end of the bone, is the most common site for fractures and accounts for 8% to 15% of all bone injuries in adults. Pain on the outer forearm a few inches below the elbow often points to nerve compression. Pain right at the bony bump on the thumb side of your wrist, especially when you grip or pinch, suggests a tendon problem rather than the bone itself.
If the pain started suddenly after a fall or impact, a fracture is the most likely explanation. If it crept in gradually over days or weeks, overuse injuries, nerve irritation, or tendon inflammation are more probable.
Fractures at the Wrist End
Distal radius fractures, meaning breaks near the wrist, are by far the most common radius injury. They happen at a rate of about 203 per 100,000 people per year, with women affected roughly three and a half times more often than men. After menopause, the incidence in women climbs sharply because of declining bone density. In younger people, these fractures typically result from high-energy impacts like sports collisions or falls from height. In older adults, a simple fall onto an outstretched hand is often enough.
Two classic patterns exist. A Colles fracture happens when you catch yourself with your palm open and your arm extended. The broken fragment of bone shifts toward the back of the wrist, creating a visible “dinner fork” deformity when viewed from the side. A Smith fracture is essentially the reverse: a fall onto a flexed wrist or a blow to the back of the hand pushes the fragment toward the palm side, producing a “garden spade” shape. Both cause immediate pain, swelling, and difficulty moving the wrist.
Recovery after a distal radius fracture is slower than most people expect. Even with surgical repair, wrist function tends to be at its worst around the six-month mark, then gradually improves over the following year. At one year, about 44% of patients still haven’t returned to their pre-injury function. Improvement continues for up to five years, but roughly 29% of people still report meaningful limitations at that point.
Fractures Near the Elbow
The top of the radius, called the radial head, sits just below your elbow and lets you rotate your forearm (turning your palm up and down). A fall onto an outstretched hand can crack this part of the bone too, though it’s less common than wrist fractures. The hallmark symptom is difficulty or inability to rotate your forearm, along with pain on the outer side of the elbow. Even mild radial head fractures result in some loss of elbow movement, and physical therapy is almost always part of the recovery process. In severe cases, scar tissue can limit motion enough to require a second procedure.
Stress Fractures From Repetitive Use
Unlike acute fractures that happen in a single moment, stress fractures develop over weeks of repetitive loading. They’re tiny cracks in the bone that worsen with continued activity. In the radius, stress fractures are less common than in the legs and feet but do occur, particularly in gymnasts and other athletes who bear weight through their hands and wrists. The pain typically builds during activity and eases with rest, then eventually becomes constant if ignored. X-rays often miss early stress fractures, so an MRI or bone scan may be needed to confirm the diagnosis.
Radial Tunnel Syndrome
If your pain runs along the outer forearm about 5 centimeters (roughly 2 inches) below the elbow and gets worse at night, radial tunnel syndrome is a strong possibility. This condition occurs when the radial nerve gets compressed as it passes through a narrow space between muscles in the forearm. It’s frequently confused with tennis elbow, but the key difference is location: tennis elbow causes tenderness directly on the bony point of the outer elbow, while radial tunnel syndrome hurts a couple of inches farther down the forearm.
A few simple movements can help identify it. Pain that flares when you extend your middle finger against resistance, or when you twist your forearm palm-up against resistance, points strongly toward radial tunnel syndrome. The pain often worsens when you straighten your elbow while turning your forearm palm-down and bending the wrist, because these positions stretch the nerve. Unlike some nerve problems, radial tunnel syndrome typically causes pain and fatigue without obvious numbness or muscle weakness.
De Quervain’s Tenosynovitis
This condition affects the tendons on the thumb side of your wrist, right where they cross over the radius bone. It can feel like the bone itself is hurting, but the source is inflamed tendon sheaths. The telltale signs are pain and swelling near the base of the thumb, a catching or “stop-and-go” sensation when moving the thumb, and worsening pain with gripping or pinching motions. If left untreated, the pain can spread into the thumb and up the forearm.
A quick way to check is the Finkelstein test: tuck your thumb into your fist, then bend your wrist toward your pinky finger. A sharp spike of pain over the bony bump on the thumb side of your wrist strongly suggests De Quervain’s rather than a bone problem. This condition is common in new parents (from repeatedly lifting a baby), office workers, and anyone who does repetitive hand and thumb movements.
When Radius Pain Is an Emergency
Most causes of radius pain are not dangerous, but compartment syndrome is a rare and serious exception. It happens when swelling inside the forearm builds pressure to the point where blood can’t reach the muscles and nerves. This typically follows a significant injury like a fracture, and symptoms develop within hours (sometimes up to 48 hours after the injury). The forearm becomes swollen, tense, and extremely tender. The defining feature is pain that seems far worse than the injury should cause, especially when someone gently straightens your fingers. Rest and pain medication don’t help. Numbness or tingling may follow, and paralysis is a late sign. If you notice these symptoms after a forearm injury, this requires immediate medical attention because outcomes range from full recovery to permanent damage depending on how quickly it’s treated.
Narrowing Down the Cause
You can often get a reasonable sense of what’s going on before you see anyone by considering three things: how the pain started, exactly where it hurts, and what makes it better or worse.
- Sudden onset after a fall or impact, with swelling near the wrist: likely a distal radius fracture, especially if the wrist looks deformed or you can’t move it.
- Pain on the outer elbow that limits forearm rotation after a fall: possible radial head fracture.
- Gradual onset along the outer forearm, worse at night: radial tunnel syndrome.
- Pain at the thumb-side wrist bump with gripping or pinching: De Quervain’s tenosynovitis.
- Activity-related pain that builds over weeks, eases with rest: possible stress fracture.
A physical exam can usually distinguish between these conditions, and imaging with X-ray or MRI confirms the diagnosis when needed. The specific location of tenderness, measured even in centimeters, often makes the difference between one diagnosis and another.