Latissimus Dorsi – The Largest Back Muscle
Ever wonder why famous bodybuilders have that “V” shape in their bodies? It is because they have a very well developed latissimus dorsi. Getting a V-shaped body is defined by having a smaller waist than your chest and well-defined latissimus dorsi muscles. Also prominent in swimmers, it is visible winging out from behind the ribcage under each arm and is involved in a wide variety of movements.

Muscles of the back are among some of the largest in the human body, and the lat muscle is the largest of these. The mid-back muscles include the latissimi dorsi (lats), rhomboids, and teres major.
The latissimus dorsi (“the lats”) is definitely the widest muscle in the human body and also the largest and most powerful muscle in the back. It is relatively thin and covers almost all back muscles at the posterior trunk (except the trapezius).
As you can see from the picture, your latissimus dorsi originates on the lower half of your back, along your spine and hip, and attaches to the inside of your upper arm.
The lats are superficially located, which means they are clearly visible (when the skin is removed). In other words, you don’t have to dissect away layers of muscles to locate the lats.
The “lats,” as they’re commonly referred to, are also called the “wings” because of their flared, wing-like appearance when they are well developed.
Once large enough, the lats are responsible for your body’s “V-taper” because of their protruding appearance under your armpit area and on the back of your ribs.
And as you might guess, they are the back muscles most commonly targeted by lifters in the gym. However, many fail to give them the proper attention required to reach their full potential.
The main job (function) of the lats is to bring the upper arm bone (the humerus) down and behind the body. When your arm is fixed, such as during a pullup, the lats pull the entire weight of your body toward the arm.
To target your lats, you can use a variety of popular back exercises, including lat pull downs, pull ups, barbell bent over rows, dumbbell one arm rows, and deadlifts.
