posted by Signature Medical Group on Monday, December 18, 2017
The rotator cuff is a group of muscles and tendons that surround the shoulder joint, keeping the head of your upper arm bone firmly within the shallow socket of the shoulder, the Mayo Clinic adds. A rotator cuff injury can cause a dull ache in the shoulder, which often worsens when you try to sleep on the involved side. The risk of rotator cuff injury increases with age.