The latissimus dorsi is a large superficial muscle of the middle back. Prominent in swimmers, it is visible winging out from behind the ribcage under each arm and is involved in a wide variety of movements. The name latissimus dorsi comes from Latin and translates to “broadest muscle of the back.” While it is indeed a large muscle used during many movements, the latissimus dorsi muscle is commonly very tight and can contribute to upper cross syndrome, a postural condition in which the shoulders round forward and inward and head juts forward that can lead to neck pain and headaches.
Triangular in shape, the broadest side of the latissimus dorsi muscle attaches along the spine from the ribcage all the way down to the hipbones and converges to insert into the humerus bone along the underside of the upper arm. It is responsible for a number of functions at the shoulder joint. The latissimus dorsi extends the shoulder, or draws the arm down toward the body when it is raised to the front. It also adducts the shoulder, or draws the arm down toward the body when it is raised to the side. Additionally, the latissimus dorsi muscle assists in lifting the arm overhead, in horizontally abducting the arm, or pulling it horizontally away from the body when it is raised in front to shoulder height, and in internally rotating the shoulder, or turning it inward.
The latter action of the latissimus dorsi muscle, internal rotation of the shoulder joint, is of particular significance to upper cross syndrome. Due to both its size and its involvement in so many movements, the latissimus dorsi is quick to become tight and overused, whether from sitting at a desk with shoulders rounded inward or from allowing the shoulders to rotate internally during lifting movements like lat pull downs and bench presses. This internal rotation can kick off a sequence of related muscle imbalances, from tight pectoral muscles in the chest to a tight trapezius, which shrugs the shoulders, to tight neck extensors, which push the head forward.
To help correct these muscle imbalances, it is therefore important to stretch the latissimus dorsi muscle as well as maintain proper shoulder rotation during exercises that use this muscle. Holding the chest open and rotating the shoulders back while engaging the upper back muscles that draw the shoulder blades together helps prevent reinforcement of upper cross syndrome while performing lat pull downs, chin-ups, and bench presses. Likewise, the latissimus dorsi should be stretched regularly. It is recommended that in order to stretch this muscle, one should grasp an overhead bar with arms fully extended vertically and hang, ideally with feet remaining on the floor, using one’s body weight to place a stretch on the muscle.