Muscle of the Month - Latissimus Dorsi
By Susie Black - get free updates of new articles here
Stick your hands up!
What is it? This is a broad, flat sheet of muscle encasing much of our back. Where is it? It's a superficial muscle, which means that it runs under our skin rather than deep into the torso. It's such a large sheet of muscle fibres that it fixes onto many points of our body and runs in several different directions. The origin points of the muscle (where they stem from) are vast and include much of the mid and lower length of the spine, some of the lower ribs, the rise of the pelvis at the back and the underside of the shoulder blade. The insertion point (where the muscle attaches to create movement) is small; the muscle fibres gather together, intertwining with some of the shoulder blade muscles to wind through the shoulder joint and fix into the upper arm.
What does it do?
Think of the strength required to open out a a bird's wing; as you raise your arm these muscle fibres are lengthened and when they contract they pull your arm back downwards. It might also help to think of this as the climbing muscle. Picture yourself climbing a tree and reaching up to grab a branch. As you pull yourself upwards these muscles are activating.
How do I activate it? You activate it by pulling yourself upwards by your arms or drawing your arms in towards your sides from above, such as during the breaststroke in swimming
Why do we need them? It helps us take things from high shelves, climb, row in a boat, reach upwards, swim and create movement around the shoulder. It's also used when we sneeze or take large breaths. This muscle works in accordance with some of the deep shoulder muscles so improper use will impact shoulder and upper spine mobility. As it also has attachment points in the lower back and pelvis it can impact lower back pain if overly tight. Ongoing research is attempting to measure this muscle's impact on the movement of the trunk however it's impact on our back comfort cannot be underestimated simply because of the many points to which it fixes.