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What is a Subacromial Bursa?

Definition: Inflammation of the subacromial bursa

In the shoulder there are four main bursae:

  1. Subacromial bursa – which is located just under the acromion process and supraspinatus muscle (close to the humeral head aka, the greater tuberosity of the humerus), its function is to prevent/reduce friction between the acromion and the rotator cuff tendons in the subacromial space.
  2. Subscapular bursa – which is located between the shoulder joint capsule and the tendon of the muscle called subscapularis.
  3. Subdeltoid bursa – is located between the shoulder joint and deltoid muscle, however this bursa is usually “attached” to the subacromial bursa and is sometimes not distinguishable as a separate bursa.
  4. Subcoracoid bursa – is located between the shoulder joint capsule and coracoid process on the scapula.

What are they?

Bursae are fluid-filled sacs and situated where muscles, ligaments, tendons and skin rub across bone. They secrete small amounts of lubricating fluid that’s rich in protein and collagen. They absorb shock and provide a lubricated gliding surface for soft tissues to move over bones without suffering a friction injury.

What Causes Subacromial Bursitis?
Subacromial bursitis most often occurs for one or two main reasons and some lesser known causes:

  • Blunt force or more pressure.

During trauma, the bursa becomes filled with blood and become inflamed and when caused by pressure or friction, the bursa begins to produce too much lubricating fluid. If the friction or pressure continues the bursa continues to fill will the excess fluid and become inflamed.

  • Repetitive Strain injury

The subacromial bursa often becomes inflamed following: tendonitis of the supraspinatus tendon, a rotor cuff injury, impingement syndrome or a bone spur. It is common among  people who take part in sports, some occupational careers, or hobby that involves frequent and/or repetitive overhead arm movements like badminton, swimming, painting, or even throwing a ball.

  • An infection i.e. septic bursitis. This is sometimes due to a systemic infection, but is more often a localized infection after a direct trauma produces an open wound near a shoulder bursa.
  • Lifting or Poor Manual Handling.

Lifting objects or people where the arms rise above the height of the shoulder will cause an increased downwards force upon clavicle and can cause impingement or trapping of the bursa.

The Symptoms of Subacromial Bursitis?

  • Localized pain, swelling, tenderness to the touch, warmth to the touch.
  • Shoulder motions may produce a sharp stabbing pain once the height of the arm comes in line or above the height of the shoulder.
  • Deep dull ache, burning sensation, or pain severe enough to limit motion.
  • A feeling of heaviness in the arm.

Things to know!

  • The acute stage starts the moment an injury occurs and lasts until the swelling and inflammation are gone (usually 2-3 days).
  • The sensation or feeling of heat is due to the increased blood and fluids in the area causing overheating in the injured shoulder as they back up and accumulate.
  • If any ligaments and tendons stretch and tear, blood from the ruptured blood vessels become trapped in the local tissues.
  • During the acute stage it is vital that normal circulation is restored to the shoulder, clotted blood and stagnant fluids broken up, reduce swelling, and/or reduce the redness and heat associated with inflammation.

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