The subacromial bursa is a fluid-filled sac that cushions and
lubricates the outer surface of the rotator cuff in the shoulder. This
lubrication helps to reduce friction with movement.
The shoulder is a ball-and-socket joint with three main bones that
are held together by muscles, tendons, ligaments, and the joint capsule. The
rotator cuff is a group of tendons known as the supraspinatus, infraspinatus,
subscapularis, and teres minor. These tendons help keep the upper arm bone
securely placed, or seated, into the socket of the shoulder blade and allow the
shoulder to move in various directions.
The subacromial bursa is located between the upper tendon of the
rotator cuff (supraspinatus tendon) and the outer corner of the shoulder blade
(acromion).