Pain at the back of the elbow usually comes from one of three structures: the bony tip (called the olecranon), the fluid-filled cushion that sits over it, or the triceps tendon that attaches to it. The cause ranges from something as simple as leaning on your elbows too long to overuse injuries from sports or lifting. Figuring out which structure is involved comes down to what the pain feels like, what triggered it, and whether there’s visible swelling.
Key Structures Behind the Elbow
The back of your elbow is dominated by the olecranon, the bony point you can feel when you bend your arm. The triceps muscle on the back of your upper arm connects to this bone through a thick tendon. Sitting right over that bony tip is a small, fluid-filled sac called the bursa, which acts as a cushion between the bone and the skin. Any of these three structures, plus the ulnar nerve that runs along the inner-back edge, can be the source of your pain.
Olecranon Bursitis
If the back of your elbow is visibly swollen, with a puffy, egg-like bump right over the bony tip, the most likely culprit is bursitis. The bursa has become inflamed, and it fills with extra fluid. More than two-thirds of cases are caused by trauma or repetitive pressure rather than infection. Common triggers include leaning on your elbows at a desk for long stretches, a direct blow during a fall, or repetitive motions in sports like baseball.
Bursitis from pressure or minor trauma typically causes swelling and mild tenderness but not much redness or heat. If the bursa becomes infected (septic bursitis), you’ll notice redness, warmth, skin discoloration, and sometimes fever. Septic bursitis needs prompt medical attention and antibiotics. Chronic bursitis, where the bursa has been irritated repeatedly over months, can leave a rubbery, mobile lump that isn’t particularly tender but limits how far you can fully bend or straighten the elbow.
Triceps Tendonitis
If your pain is more of an ache that flares when you push, press, or straighten your arm against resistance, the triceps tendon is the more likely problem. This is an overuse injury. It develops from repeated forceful extension of the elbow: bench pressing, dips, push-ups, throwing, or even hammering. Poor form during these movements accelerates the damage.
The hallmark symptoms are pain with movement (especially pushing motions), swelling along the tendon, and sometimes a grating sensation when you extend the arm. The skin over the tendon can become red and warm. Unlike bursitis, triceps tendonitis doesn’t produce a distinct puffy lump. Instead, the tenderness is located slightly above the bony tip, right where the tendon meets the bone, and it hurts most when you try to straighten your elbow against force.
How to Tell It Apart From Bursitis
A simple self-check: if the swelling sits right on top of the bony point and feels like a fluid-filled pouch, that points to bursitis. If the pain is triggered specifically by resisted elbow extension (pushing a door open, doing a push-up) and the tenderness is just above the bone rather than directly over it, that points to the tendon. Bursitis can limit your range of motion at the extremes of bending and straightening, while tendonitis primarily hurts during active pushing and may slightly weaken your arm because pain inhibits full effort.
Posterior Impingement
Athletes who repeatedly snap their elbow into full extension, especially throwing athletes and people who do a lot of dips or chest presses, can develop posterior impingement. This happens when the olecranon gets jammed into the bony groove at the bottom of the upper arm bone over and over, compressing the tissue between them. Over time, bone spurs can form, making the pinching worse.
This condition is sometimes called “pitcher’s elbow” and causes a deep, aching pain at the back of the elbow that peaks right at the moment of full extension. It tends to build gradually over a season or training cycle rather than appearing suddenly.
Ulnar Nerve Irritation
The ulnar nerve runs through a groove on the inner-back side of the elbow. It’s the nerve you hit when you bang your “funny bone.” When this nerve gets compressed or irritated repeatedly, the result is cubital tunnel syndrome. Symptoms include elbow pain combined with numbness and tingling in the pinky and ring fingers. These sensations often worsen at night or during activities that bend the elbow for long periods, like sleeping with your arm folded or talking on the phone.
If your posterior elbow pain comes with tingling or numbness radiating into your hand, nerve involvement is likely part of the picture.
Stress Fractures
Less common but worth knowing about: the olecranon can develop a stress fracture, particularly in throwing athletes. The pain is localized to the bony tip, worsens with throwing, and improves with rest. There’s usually mild swelling and point tenderness right on the bone. Unlike soft tissue injuries, stress fractures don’t always show up on initial X-rays. A CT scan or MRI is often needed to confirm the diagnosis. If resting relieves your pain but it returns every time you throw or load the elbow, this possibility is worth investigating.
First Steps for Relief
For most cases of posterior elbow pain, conservative treatment works well. The first priority is stopping whatever activity triggered the pain. Apply ice or a cold pack for 15 minutes, three to four times a day, to reduce inflammation. Over-the-counter anti-inflammatory medications like ibuprofen or naproxen can help with both pain and swelling.
If the pain is tied to a sport or work task, look closely at your technique and equipment. Poor form during pressing exercises or throwing is a major driver of triceps tendon problems and impingement. A physical therapist can evaluate your movement patterns and prescribe strengthening exercises for the muscles around the elbow.
Recovery timelines vary. Mild bursitis from a single episode of pressure or a bump can resolve in a couple of weeks with rest. Triceps tendonitis typically needs several weeks to a few months of modified activity. If conservative treatment hasn’t made meaningful progress after about six months, or if you notice significant weakness in the arm, surgical options may come into consideration. For tendonitis, initial treatment sometimes includes a short period of splinting with the elbow slightly bent to take tension off the tendon.
Signs That Need Urgent Attention
Most posterior elbow pain is manageable at home, but certain symptoms warrant a prompt visit. Redness, warmth, and swelling combined with fever suggest the bursa may be infected. Redness that spreads up or down the arm from the elbow is another warning sign. Inability to straighten the arm at all, sudden severe pain after a pop, or visible deformity could indicate a tendon rupture or fracture. If you develop chest pain, shortness of breath, or dizziness alongside arm symptoms, seek emergency care.