Impingement occurs when inflammation, bone spurs, or fluid buildup
rotator cuff tendon to be squeezed and rub against a
Every time you raise your arm above your head, the upper tendon in
the rotator cuff (supraspinatus tendon) and the
bursa that lies on top of the tendon glide on the
underside of the upper end of your shoulder blade (acromion).
The underside of the acromion may be rough and
rub or scrape (abrade) the bursa and tendon.
require repeated overhead arm movements can result in painful inflammation of
the bursa (bursitis) and/or the tendon (tendinitis).
Over time, the tendon may wear against the underside of the
Tiny tears may develop.
Then, the tendons in the rotator cuff can no longer
balance the upward pull of the shoulder muscle (deltoid) on the
head of the upper arm bone. This can lead to further damage to the rotator cuff
tendon. The weaker the
tendon becomes, the more likely it is to get partially or completely torn.