Pes Anserine Bursitis: The Sore Spot Below Your Knee

Pes anserine bursitis is the name for a tender, aching spot on the inner side of your shin, about two inches below the knee joint. It is a small area, roughly the size of a coin, and it is usually sore when you press it with one fingertip. Stairs make it worse, so does getting out of a car, and so does lying on your side at night with your knees touching.

The name comes from anatomy, not from anything sinister. Three thigh muscles, the sartorius, the gracilis, and the semitendinosus, all send their tendons down to the same patch of bone on the inner shin. Their spread out shape reminded early anatomists of a goose's foot, which is what pes anserinus means. A small fluid sac, the bursa, sits underneath them.

Knee trouble in general is very common. Of the joints affected by osteoarthritis worldwide, the knee is the one most often involved, at about 365 million people (WHO, 2023). Pes anserine pain frequently turns up alongside an arthritic knee, which is one reason it gets missed.

What pes anserine bursitis actually is

The traditional picture is an inflamed bursa: the little sac swells, and pressing it hurts.

The picture has shifted. When people with exactly this pain pattern are scanned, the bursa often looks completely normal, with no extra fluid in it. So a good many clinicians now describe the problem as irritation of the tendons where they attach, and call it pes anserine pain syndrome rather than bursitis.

That is not a distinction worth losing sleep over. What matters is what the tissue is telling you. Something in that corner of the knee has been asked to do more than it was ready for, and it has become sensitive. Our Feldypedia article on bursitis covers the family of conditions this belongs to.

Who tends to get pes anserine bursitis

A few patterns show up repeatedly.

• Alongside knee arthritis. An arthritic knee changes how load travels, and the inner side often picks up the difference.
• After a jump in activity. A new walking habit, a longer route, more hills, or a return to running after a break.
• Breaststroke swimmers. The kick loads the inner knee directly.
• People carrying more weight. More load through a knee that is already working at the edge of its tolerance.
• Women more often than men, which is usually explained by pelvis width and the angle it gives the thigh, though the evidence there is softer than the confidence with which it is repeated.

None of these is a verdict. They are patterns, and knowing which one is yours tells you what to change.

What helps pes anserine bursitis settle

The first job is to take the pressure off, without stopping altogether.

Reduce what irritates it. Deep squats, lunges, cross legged sitting, long downhill stretches, and breaststroke are the usual culprits. Take them out for a few weeks rather than for ever.

Sleep with a pillow between your knees. Simple, and it removes hours of direct pressure on the sore spot every night.

Keep the knee moving without load. Slow bending and straightening while sitting or lying keeps the joint comfortable and does not ask the tendons to carry you.

Look above the knee. The inner knee often takes extra load when the hip is not doing its share of the steadying. That is why work for the hip and pelvis frequently helps a knee complaint more than anything aimed at the knee itself.

Return gradually. Add distance or hills back in small steps. A sudden full return is the most common way people restart the whole cycle.

Ice and short courses of anti inflammatory medicine help some people through the sore phase. They are worth discussing with a pharmacist or doctor rather than assuming.

Why gentler movement often beats a harder stretch

Sensitive tendon tissue does not respond well to being pulled on. A firm stretch into the tender area tends to give an hour of relief and a day of soreness, which is why people who stretch it hardest often report the least progress.

Slow, small movement done with attention is a different proposition. The Feldenkrais Method® works this way throughout: rather than forcing a sore area toward its limit, it gives the whole leg easier options so the irritated corner stops being the part that absorbs everything. If you want a place to begin, our knee proprioception exercises build a clearer sense of where your knee is and how your weight arrives on it, which is the piece most people are missing. Our knee bursitis exercises cover the same territory for the front of the knee, and our guide to exercises to avoid for knee pain lists what usually makes things louder. The Feldy program for knees and hips puts the whole approach on a weekly footing.

A note on care

This page is background, not a diagnosis. Inner knee pain can also come from a meniscus, from the medial collateral ligament, from a stress reaction in the bone, or from a referred hip problem, and only an examination can sort them out. Please get help quickly for a knee that is hot, red, and swollen with a fever, or one you cannot stand on. Where a physiotherapist is already treating you, use this as background reading and follow their plan.

Find where to start

Inner knee pain sends people in several directions at once: stretch it, ice it, rest it, load it. The right first move depends on what is driving it.

Not sure which approach suits a sore knee? Take the 60 second Movement Match quiz. Three questions, one method chosen for the way your knee behaves rather than for the label on it.

Common Questions about pes anserine bursitis (FAQ)

What does pes anserine bursitis feel like?

A tender, aching spot on the inner side of the shin, roughly two inches below the knee joint and slightly toward the back. It is usually sore to press with one fingertip. People notice it most going up or down stairs, standing up from a low chair, getting out of a car, and lying on their side at night with the knees touching. There is often no visible swelling at all.

What is the best exercise for pes anserine bursitis?

The best early exercise is gentle, unloaded knee bending and straightening, done sitting or lying rather than standing. It keeps the joint moving without asking the sore tendons to carry your body weight. Once that is comfortable, slow controlled work for the hip and thigh usually helps more than stretching the sore spot, because the area often gets overloaded when the hip is not sharing the work.

What should I avoid with pes anserine bursitis?

Avoid deep squats and lunges, sitting cross legged, breaststroke kick, and long downhill walking, all of which load the inner knee. Avoid stretching hard into the tender spot, since irritated tendon tissue rarely responds well to being pulled on. Avoid sleeping with the knees pressed together, and put a pillow between them instead. And avoid a sudden jump in walking or running distance, which is a common trigger.

How long does pes anserine bursitis take to settle?

Many people improve noticeably within two to six weeks of reducing the aggravating load and moving more gently. Longer standing cases, particularly alongside knee arthritis or after months of the same activity, can take three months or more. Recovery tends to be uneven, with good weeks and setbacks. Steady, gradual return of activity works better than resting completely and then starting again at full speed.

How is pes anserine bursitis different from knee arthritis?

Location is the clearest clue. Pes anserine pain sits below the joint line, on the inner shin, and is tender under one fingertip. Arthritic knee pain sits in the joint itself, feels more diffuse, and often comes with morning stiffness and a grinding sensation. The two frequently occur together, which is part of why inner knee pain in an older adult deserves an examination rather than a guess.

Is pes anserine bursitis really a bursitis?

Often not, in the strict sense. Scans of people with this exact pain pattern frequently show no fluid in the bursa at all, so many clinicians now call it pes anserine pain syndrome and treat it as irritation of the tendons where they meet the bone. The practical difference is small: either way, the answer is less irritating load and a gradual return, not a stronger stretch.

When should I see a doctor about pain below the knee?

See a doctor promptly if the knee is hot, red, and swollen, especially with a fever, or if you cannot put weight through the leg. Get it looked at if the knee locks, gives way, or swelled up quickly after a twist or a fall. Book an appointment for pain that has not improved after six weeks of sensible self care, or that wakes you every night.