Ischial bursitis is inflammation of a small, fluid-filled sac (called a bursa) that sits between your “sit bones” and the large muscle of your buttock. Your sit bones, technically the ischial tuberosities, are the bony points at the bottom of your pelvis that bear your weight when you sit. The bursa normally acts as a cushion, reducing friction between the bone and the overlying gluteal muscle. When it becomes irritated and swollen, the result is a deep, aching pain right where you sit.
Where the Ischial Bursa Sits
The ischial bursa lies deep beneath the gluteus maximus, positioned just below and slightly toward the inner edge of each ischial tuberosity. It sits medial to (on the inside of) the hamstring tendons, which attach to the outer-lower surface of the same bone. This location means the bursa gets compressed every time you sit on a hard surface, and it experiences friction whenever the gluteal muscle slides over the bone during walking, running, or climbing stairs.
Most people have two of these bursae, one under each sit bone. You can feel the ischial tuberosities yourself by sitting on a hard chair and rocking slightly. The hard points pressing into the seat are the bones the bursa is designed to protect.
Common Causes
The most frequent trigger is prolonged sitting, especially on hard surfaces. This is why ischial bursitis has historically been called “weaver’s bottom” or “tailor’s bottom,” after occupations that involved sitting for long hours on hard benches. Office workers, cyclists, and rowers are at risk for the same reason: sustained or repetitive pressure on the sit bones.
Other causes include:
- Repetitive friction: Activities involving repeated hip flexion and extension, like running, lunging, or climbing, create friction between the gluteal muscle and the ischial tuberosity, irritating the bursa over time.
- Direct trauma: A fall onto the buttocks can cause acute inflammation or even bleeding into the bursa.
- Hamstring strain: Because the hamstring tendons attach right next to the bursa, injuries or tightness in the hamstrings can irritate it.
- Muscle imbalance: Weak or tight gluteal and hip muscles change how force is distributed across the pelvis, placing extra stress on the bursa.
People who are thin or have lost significant weight sometimes develop ischial bursitis more easily because they have less natural padding over the sit bones.
What It Feels Like
The hallmark symptom is a deep, dull ache centered on the sit bone, typically on one side. The pain is worst when sitting, especially on hard chairs, and tends to ease when you stand or walk. Many people describe it as feeling like they’re sitting on a golf ball.
The pain can radiate down the back of the thigh, which sometimes leads to confusion with sciatica or a hamstring injury. Unlike sciatica, ischial bursitis pain rarely extends below the knee and doesn’t typically cause tingling or numbness in the foot. It’s also distinct from piriformis syndrome, which produces pain deeper in the buttock and tends to worsen with internal rotation of the hip.
Activities that stretch or load the hamstrings, like bending forward, climbing stairs, or running uphill, often make the pain worse. Lying on the affected side can also be uncomfortable at night.
How It’s Diagnosed
A physical exam is usually enough to make the diagnosis. Pressing directly on the ischial tuberosity reproduces the pain, and stretching the hamstring on the affected side often intensifies it. Your doctor may also check for tenderness along the hamstring tendons to rule out a tendon tear.
When the diagnosis is unclear or symptoms don’t improve, MRI can confirm the presence of an enlarged, inflamed bursa. On imaging, the swollen bursa appears as a fluid-filled sac sitting just below and to the inner side of the ischial tuberosity, deep to the gluteal muscles. In a study of 17 patients with confirmed ischial bursitis published in the Korean Journal of Radiology, all cases showed bright fluid signal on certain MRI sequences, and about 70% had irregular inner walls from chronic inflammation and internal scarring. Some cases also showed blood-fluid levels inside the bursa, indicating bleeding from trauma or chronic irritation.
Ultrasound is another option that’s quicker and less expensive, and it can detect fluid collection around the ischial tuberosity in real time.
Treatment and Recovery
Most cases of ischial bursitis resolve with conservative measures. The single most important step is reducing pressure on the bursa. That means avoiding prolonged sitting on hard surfaces and, when you do need to sit, using a cushion designed to offload the sit bones. Donut-shaped pillows, memory foam cushions with cutouts for the ischial tuberosities, or inflatable ring cushions all work by shifting your weight to the surrounding soft tissue instead of directly onto the bone.
Ice applied to the area for 15 to 20 minutes several times a day helps reduce swelling in the early stages. Over-the-counter anti-inflammatory medications like ibuprofen or aspirin can manage both pain and inflammation.
As symptoms improve, physical therapy becomes the focus. A therapist will typically work on stretching the hamstrings and hip flexors, strengthening the gluteal muscles, and correcting any pelvic muscle imbalances that contributed to the problem. The goal is to reduce the mechanical stress on the bursa so it doesn’t flare up again once you return to normal activity.
Mild cases often improve within a few weeks with rest and activity modification. Chronic cases, particularly those caused by months or years of repetitive irritation, can take several months of consistent treatment. If conservative measures fail after an extended period, a corticosteroid injection into the bursa can provide significant relief by directly reducing inflammation. This is typically guided by ultrasound to ensure accurate placement.
When Surgery Is Considered
Surgery for ischial bursitis is rare and reserved for cases that haven’t responded to months of conservative treatment and injections. The procedure, called a bursectomy, involves removing the inflamed bursa entirely. It can be performed endoscopically through small incisions. The body doesn’t typically regenerate the bursa afterward, and the surrounding tissues adapt to function without it. If a partial hamstring tear is found alongside the bursitis, the surgeon may repair the tendon at the same time.
Practical Changes That Help
Because sitting is the primary aggravator, making your daily seating setup more bursa-friendly can make a meaningful difference in both treatment and prevention. A pressure-relieving seat cushion with cutouts for the sit bones is the most practical investment. These are available in memory foam, gel grid, and inflatable designs. Place one on your office chair, car seat, and anywhere else you sit for extended periods.
Standing desks or sit-stand workstations let you alternate positions throughout the day, giving the bursa regular breaks from compression. If you can’t stand, even shifting your weight from side to side or standing up for a minute every 30 minutes reduces cumulative pressure.
For runners and cyclists, adjusting training volume and ensuring proper bike fit (particularly saddle height and tilt) can prevent recurrence. Hamstring and glute stretching before and after exercise keeps the surrounding muscles flexible and reduces friction over the ischial tuberosity. A consistent strengthening program for the glutes and core helps distribute forces more evenly across the pelvis, taking the burden off the bursa long-term.