Rotator cuff injury can be a tendinitis, a strain, or a tear of the rotator cuff muscles. The rotator cuff is made up of four tendons that fuse to surround the shoulder joint.
Neck cracking or neck popping is caused by quick movements to loosen the ligaments and joints of the neck. Cracking can occur in the knuckles, lower back, hips, ankles and toes. Rarely, neck popping may puncture blood vessels.