Impingement is one of the most common causes of shoulder pain in workers who use their hand above the shoulder level. It results from pressure on the rotator cuff from part of the shoulder blade (scapula) as the arm is lifted.

The rotator cuff helps to lift and rotate the arm and to stabilize the ball of the shoulder within the joint. Workers that suffer from impingement can weaken the rotator cuff to the point where it tears.

The labrum is the cartilage rim that surrounds the socket of the shoulder joint. The labrum can tear when a worker falls and hangs by their arm. The labrum can also tear as an occupational injury when the arm is used forcibly overhead.

Falling on the outstretched arm is a common way that workers break the bones that make up the shoulder joint.