What is Bursitis
A bursa is a fluid-filled sac that reduces friction around your joints. When the bursa becomes inflamed (swollen) because the fluid inside is infected or irritated by too much movement, this is called bursitis. It causes pain, swelling and difficulty moving the affected joint.
When the condition called bursitis occurs, the normally slippery bursa becomes swollen and inflamed. The added bulk of the swollen bursa causes more friction within an already confined space. Also, the smooth gliding bursa becomes gritty and rough. Movement of an inflamed bursa is painful and irritating.