The bony point at the tip of your elbow is supposed to stick out. It’s called the olecranon, and it’s the top end of your forearm bone (the ulna) that forms the hinge of your elbow joint. In thin or muscular people, it can look quite prominent, especially when the arm is bent. But if the protrusion seems new, bigger than usual, soft or swollen, or painful, something else may be going on.
The Bone You’re Probably Feeling
When you bend your arm, the olecranon slides backward and becomes the most prominent structure at your elbow. It’s the attachment point for your triceps muscle, the large muscle on the back of your upper arm. That connection is why you can feel it shift and become more or less visible depending on your arm position. In people with less body fat or more defined muscles, the olecranon naturally juts out more. This is completely normal anatomy, not a sign of a problem.
The olecranon also acts as a mechanical block that keeps your forearm from sliding forward relative to your upper arm. It’s load-bearing and sits right under the skin with very little padding, which is why bumping it hurts so much and why even small changes in the area are easy to notice.
Olecranon Bursitis: The “Popeye Elbow”
If the bump at your elbow is soft, squishy, and appeared relatively recently, you’re likely dealing with olecranon bursitis. A thin, fluid-filled sac called a bursa sits between the olecranon bone and your skin, acting as a cushion. When that sac gets irritated, it fills with extra fluid and swells up, sometimes to the size of a golf ball. The nickname “Popeye elbow” comes from how dramatically it can bulge at the tip.
The most common triggers are repetitive pressure (leaning on your elbows at a desk), a direct hit to the elbow, or an infection. Swelling is usually the first thing you notice. If the skin over the bump turns red, feels warm, or you see thick yellow or white fluid draining from the area, the bursa may be infected, which needs prompt medical attention. Non-infected bursitis often improves with rest, ice, and avoiding pressure on the elbow. When swelling is severe or interferes with daily activities, a doctor can drain the fluid with a needle to relieve pressure and test the fluid to determine the cause.
Bone Spurs at the Elbow
Bone spurs are small, smooth growths of extra bone that form where your body is trying to repair wear and tear. They develop at joints and at spots where tendons or ligaments attach to bone. At the elbow, they’re most common in people who’ve used the joint heavily over many years, whether from manual labor, throwing sports, or arthritis.
A bone spur near the surface can look and feel like a hard knob under the skin. Unlike bursitis, it won’t be squishy. You might notice it only when you extend or bend your elbow fully, or it might restrict how far your arm can move. Some bone spurs cause no symptoms at all and are discovered incidentally on an X-ray. Others press on nearby nerves, causing pain, tingling, numbness, or weakness in the forearm or hand. If a hard bump at your elbow came on gradually over months or years and is accompanied by stiffness, a bone spur is a strong possibility.
Gout Deposits (Tophi)
Gout is a condition where uric acid crystals build up in and around joints. Over time, untreated gout can produce lumps called tophi: firm, chalky nodules that form just under the skin. The elbow is one of the most common sites. Tophi usually aren’t painful on their own, but they can become swollen and tender during a gout flare. If you’ve had episodes of sudden, intense joint pain (often starting in the big toe) and now notice a hard lump growing near your elbow, tophi are worth considering.
Rheumatoid Nodules
People with rheumatoid arthritis can develop firm lumps called rheumatoid nodules, and the elbow is the single most common location. These nodules form on parts of the body that experience repeated pressure or friction. They can feel like a small pebble trapped under the skin, though some are softer and squishier. Most are smaller than a pencil eraser, but in rare cases they can grow as large as a computer mouse. They tend to appear in people who’ve had rheumatoid arthritis for a while, particularly those with more active disease.
Old Injuries and Fractures
A previous fracture or dislocation that healed slightly out of alignment can leave the elbow looking different than it used to. The olecranon itself is vulnerable to fractures from falls onto an outstretched hand or direct blows. If a fracture heals with even a small amount of displacement, the bone’s profile changes permanently. You might notice one elbow looks more prominent than the other, or that you can’t fully straighten or bend the arm. A normal elbow bends to about 146 degrees and straightens to roughly 0 degrees. If your range falls noticeably short of that, a past injury may have altered the joint’s shape.
A more dramatic scenario is a fracture or dislocation you didn’t realize was serious at the time. Elbow fractures sometimes get dismissed as “just a bruise,” especially in children. Years later, the visible deformity becomes more apparent as the surrounding soft tissue thins with age.
How to Tell What’s Going On
A few simple observations can help you narrow things down before you see anyone about it:
- Hard vs. soft: A hard, immovable bump is more likely bone (the olecranon itself, a bone spur, or a tophus). A soft, fluid-filled swelling points toward bursitis.
- Sudden vs. gradual: Bursitis and fractures appear quickly, over days. Bone spurs, tophi, and rheumatoid nodules develop over weeks to months.
- Both elbows vs. one: If both elbows look the same, you’re probably just noticing normal anatomy. A difference between sides suggests something changed on one side.
- Pain and movement: If the bump limits how far you can bend or straighten your arm, or if you feel tingling, numbness, or weakness in your hand, the protrusion is affecting the joint’s mechanics or compressing a nerve.
- Redness and warmth: These suggest inflammation or infection, especially in combination with fever.
An X-ray is usually the first step if there’s any concern. It can distinguish a bone spur or old fracture from soft tissue swelling. If the lump is fluid-filled, ultrasound can confirm bursitis and help guide drainage if needed. For suspected tophi or rheumatoid nodules, blood tests for uric acid or rheumatoid factor can point toward a diagnosis.