Understanding the basic anatomy of the lats is important to know how to effectively stretch the muscle without irritating the joint by over-stressing it.

The biggest thing you want to make sure you are doing when you are stretching the lats is....stretching the lats. However obvious this may seem, frequently when people try to stretch the lats, they feel tightness on the top of their shoulder, which is an indication the lats aren't being stretched, the shoulder joint is getting to its end range of motion (meaning the bones of the shoulder are the limiting factor).

The lats literally attach your low back to your arms. The name 'latissimus dorsi', which is the technical name for the lats, literally means broadest muscle of the back.

It begins all the way down in your lower back and attaches onto your arm bone (humerus) to create shoulder joint internal rotation and extension.

Since the lats attach into your lower back, your low back positioning will affect the stretch you have on your lats. You can use these anatomical attachments to more effectively stretch the lats.