A bursa is a small, fluid-filled sac within your body that lies near bony prominences and joints. The bursa acts as a cushion between muscles, ligaments, and bones and allows structures to glide and slide past one another with ease and with minimal friction. Injury to a bursa may cause pain, limited motion, and decreased functional mobility. Fun fact: The plural of bursa is bursae.
The bursae in your body are made up of a synovial membrane. This thin membrane of tissue secretes the synovial fluid that is contained within the bursa sac. Synovial fluid is your body’s lubricant, and this viscous fluid inside the bursa allows structures in your body to glide over one another easily.
Bursae are very small and thin. The average diameter of a bursa in an adult human is about 4 cm, and each bursa is about 2 millimeters thick. The membrane of the bursa is semi-permeable, allowing some materials to flow across the membrane into and out of the sac. An injury to your bursa may cause it to fill with blood or white blood cells.
There are three main types of bursa in your body. These include:
- Synovial. Synovial bursae are most commonly found and lie near the synovial membrane of the joints of your body.
- Adventitious. The accidental bursa occur only after continued shearing or repeated pressure over a bony prominence. A bunion is an example of an adventitious bursa.
- Subcutaneous. These bursae lie between your skin and a bony prominence and allow friction-less motion of your skin over the bone. An example of this can be found on the back of the elbow.
There are about 160 bursa in your body, and the main ones can be found in areas of high bony prominence. These bursa include:
- The pre-patellar bursa. There are about five bursae that surround various areas of your knee joint, providing cushioning. They include the pre-patellar bursa, found overlying the kneecap, the suprapatellar bursa, separating the knee-cap from the thigh bone (femoral condyle) and the infrapatellar bursa, found below the kneecap overlying the patellar tendon.
- The trochanteric bursa. There is a large bursa that is located atop the bony prominence of your hip joint. This allows your gluteus medius muscle to glide and slide naturally over the bone.
- The olecranon bursa. This bursa lies between your skin and the bony prominence of your elbow.
If a bursa is surgically excised from your body, it can grow back over a few weeks’ time.
Your bursae serve to reduce friction between your body’s bony prominences and muscles, tendons, and ligaments. They help structures glide and slide past one another while movement occurs. A bursa may also provide a bit of shock absorption; the olecranon bursa in your elbow or your pre-patellar bursa in your knee may help soften a blow to those joints.
There are several conditions that may affect your bursae, causing pain, limited movement around a joint, or limited function. These may include:
- Bursitis. Bursitis occurs when a bursa becomes inflamed. The hallmarks of inflammation include pain, increased tissue temperature, and swelling. When a bursa becomes irritated due to overuse, repetitive strain, or overloading of the tissues around the bursa, it may become painful and swollen. This may make moving the joint near that bursa difficult. Common areas of your body affected by bursitis include the knee, the hip, and the shoulder.
- Calcification of a bursa. If long-term inflammation and irritation of a bursa occurs, it may cause calcification of that bursa. This most often occurs in the shoulder, and it may lead to calcific bursitis and tendonitis of your shoulder joint. This painful condition causes difficulty moving your arm.
- Infection. An infection may cause a bursa to become irritated and inflamed. Infection may be due to some local irritant or due to a rheumatic or systemic disease process.
- Gout. Deposition of urate crystals in patients with gout can occur with resultant pain or inflammation
If you suspect you have bursitis, calcification of the bursa, or bursa infection, see your healthcare provider right away. They can be sure to diagnose your condition properly and get you started on the right treatment.
If you are having a problem with your bursa around any joint, there are several different treatment options available to help.The treatment you receive depends on your condition.
If you have an inflamed bursa due to infection, your healthcare provider may prescribe antibiotic medication to treat the problem. The medicine helps to control the infection, which in turn will relieve the pain and limited motion caused by irritation of the bursa.
If you have bursitis, your healthcare provider may prescribe anti-inflammatory medication. Oral steroids may be used, and over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDS) may be effective. If oral steroids and NSAIDS prove ineffective in relieving bursa inflammation, an injection of corticosteroids may be performed, bathing the bursa and surrounding tissue in medicine that fights inflammation.
If you have bursitis or limited use of a joint due to a suspected bursa problem, your may prescribe physical therapy. Your physical therapist will assess your condition and use various treatment techniques to decrease pain and improve your ability to function.
Treatments that may be used by your physical therapist may include:
- Exercise. Your therapist may identify impairments that may be leading to an irritated bursa. This may be tight muscles, weakness, or abnormal movement patterns that are placing your bursa in a compromised position. Exercise to improve range of motion (ROM), strength, and functional mobility may be effective in relieving your current problem and preventing future problems with your bursa.
- Joint mobilization. If tightness around your joint is causing your bursa to become pinched and inflamed, your physical therapist may perform joint mobilizations. These specialized manual movement techniques can help improve the way you move and keep pressure off your inflamed bursa.
- Ice. If your bursa is inflamed, your therapist may apply ice to your body. The ice has been shown to decrease localized blood flow, helping to calm down the painful inflammation of your bursa. Keep in mind that although ice may feel good and help soothe your pain, it has not been shown to lead to improved outcomes when compared to people who do not use ice for bursitis.
- Heat. For chronic pain caused by irritation of a bursa, heat may be applied. Heat increases circulation and can bring much-needed oxygen and blood to injured bursa tissues. Use caution; heat may burn your skin, so follow your physical therapist’s directions when using heat. As with ice, using heat for bursitis may feel good, but it has not been shown to offer superior outcomes when compared to people who do not use heat for bursa problems.
- Ultrasound. Ultrasound is a deep heating treatment occasionally used in physical therapy. When ultrasound is applied to your inflamed bursa, it heats it, leading to increased blood flow which brings in oxygen and washes away inflammatory cells. Keep in mind that ultrasound has not been proven to be more effective than placebo for the treatment of inflammation in the body. Still, you may encounter it in the physical therapy clinic.
- Electrical stimulation. Your physical therapist may use a modality called electrical stimulation to help treat your bursitis. E-stim, as it is commonly called, may be used to decrease pain and improve muscle function. Another form of e-stim called iontophoresis uses electricity to introduce anti-inflammatory medication into your body.
- Massage. If tight tissues are causing your bursa to become pinched and inflamed, your physical therapist may use massage techniques to help relieve the tension. Massage can improve blood flow, decrease pain, and improve the way your body moves.
Any treatment offered by your physical therapist should be augmented by specific exercises to help your condition. You should be empowered to learn to self-manage your condition with an appropriate home exercise program, and your therapist should show you techniques to prevent future problems once your bursitis has been effectively eliminated.
Most problems with a bursa can be successfully treated with conservative measures. Bursitis and other related conditions typically last for four to six weeks. If your condition lasts longer, you may need to follow up with your healthcare provider to discuss more invasive treatments.
For the most severe cases of bursitis and conditions affecting your bursa, surgery may be performed. During the surgery, called a bursectomy, the injured or inflamed bursa may be surgically excised from the area around your joint. This removal of the damaged and inflamed bursa helps to decrease pain and relieve compression of the bursa. Keep in mind that a new bursa will grow back within a few weeks. This new bursa will not be inflamed or calcified. Working with a physical therapist and performing exercises to minimize stress on your bursa after surgery may be effective in preventing future problems with your bursa.
Many of us take pain-free movement for granted, but when pain strikes and limits your ability to move properly, you should see your healthcare provider to determine the cause of your problem and to get back to normal. If irritation of a bursa is the cause, there are several treatments that can quickly and effectively help you return to full mobility. Understanding how these small fluid-filled sacs function can help you be an informed healthcare consumer if a problem with a bursa arises.
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Hirji Z, Hunjun JS, Choudur HN. Imaging of the bursae.J Clin Imaging Sci. 2011;1:22. doi:10.4103/2156-7514.80374
Ruangchaijatuporn T, Gaetke-Udager K, Jacobson JA, Yablon CM, Morag Y. Ultrasound evaluation of bursae: anatomy and pathological appearances. Skeletal Radiol. 2017;46(4):445-462. doi:10.1007/s00256-017-2577-x
Williams CH, Sternard BT. Bursitis. In: StatPearls.
Della Valle V, Bassi EM, Calliada F. Migration of calcium deposits into subacromial-subdeltoid bursa and into humeral head as a rare complication of calcifying tendinitis: sonography and imaging. J Ultrasound. 2015;18(3):259–263. doi:10.1007/s40477-015-0163-4
Saggini R, Di stefano A, Dodaj I, Scarcello L, Bellomo RG. Pes anserine bursitis in symptomatic osteoarthritis patients: A mesotherapy treatment study. J Altern Complement Med. 2015;21(8):480-4. doi:10.1089%2Facm.2015.0007(Video) The subdeltoid joint and the serous bursae of the shoulder
Meade TC, Briones MS, Fosnaugh AW, Daily JM. Surgical outcomes in endoscopic versus open bursectomy of the septic prepatellar or olecranon bursa. Orthopedics. 2019 Mar 26:1-4. doi:10.3928/01477447-20190321-04
Seo CM, Kim K, Jeon A, Uhm CS, Lee JH, Han SH. Clinical anatomy for the innervated pattern and boundary of the subdeltoid bursa. Biomed Res Int. 2018;2018:4535031. doi:10.1155/2018/4535031
By Brett Sears, PT
Brett Sears, PT, MDT, is a physical therapist with over 20 years of experience in orthopedic and hospital-based therapy.
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Bursa, and bursas or bursae for the plural form, is an important lubricated fluid-filled thin sac located between bone and surrounding soft tissue, bones and tendons, and/or muscles around joints, and are useful to the human body by reducing tension and negative effects of wear-and-tear at points of friction and ...What are the functions of bursae and where are they located? ›
Fluid-filled, saclike cavities are known as bursae. These are located where muscles and tendons move over bony joint areas. Their function is to reduce friction caused by muscles and tendons moving against skin and bones, as well as to facilitate movement.What are the 4 types of bursae? ›
Common types of bursitis include prepatellar, olecranon, trochanteric, and retrocalcaneal.What are bursae and what is their function in the synovial joints in which they are located? ›
Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg.How many bursae are in the body? ›
There are more than 150 bursae located in your body. You're most likely to develop bursitis in joints you use over and over in the same way or in places you put a lot of pressure such as: Shoulders (subacromial bursitis). Elbows (olecranon bursitis, sometimes called miner's or barfly's elbow).Where is bursae found? ›
A bursa is a closed, fluid-filled sac that works as a cushion and gliding surface to reduce friction between tissues of the body. The major bursae (this is the plural of bursa) are located next to the tendons near the large joints, such as in the shoulders, elbows, hips, and knees.What type of tissue is a bursa? ›
Concerning bursa anatomy, the thin outer lining of a bursa is called a synovial membrane. It is a layer of connective tissue that lines bursae, joint cavities, and tendon sheaths. This membrane is made up of cells that produce synovial fluid, which is a slippery, viscous, and lubricating.What size is a bursa? ›
What Size is a Bursa? Bursae vary in size depending on where they are located in the body. The healthiest bursae are usually very thin while larger joints have larger bursae. On average, the bursa between the kneecap and skin is just a few millimeters thick and about four inches in diameter.How do you remove fluid from bursa? ›
If you have severe bursitis, your doctor may use a needle to remove extra fluid from the bursa. You might wear a pressure bandage on the area. Your doctor may also give you a shot of medicine to reduce swelling. Some people need surgery to drain or remove the bursa.What are the three types of bursae? ›
Bursae come in three packages: synovial, subcutaneous, and adventitious.
The bursae in your body are made up of a synovial membrane. This thin membrane of tissue secretes the synovial fluid that is contained within the bursa sac. Synovial fluid is your body's lubricant, and this viscous fluid inside the bursa allows structures in your body to glide over one another easily.What is the purpose of a bursa quizlet? ›
Bursas are small fluid filled sacs that function as cushioning, or lubrication, or they help to decrease friction between bone and tendon, or bone and muscle.What happens when a bursa bursts? ›
If the bursitis is left untreated, the fluid filled sack has the potential to rupture. This could then lead to an infection of the surrounding skin.