The Latissimus Dorsi, often called the “lats,” is one of the largest and most powerful muscles of the upper body. This broad muscle plays a foundational role in upper body strength and maintaining proper posture. Understanding this muscle is a first step toward improving performance in various physical activities and achieving a balanced physique. This article identifies the location of the Latissimus Dorsi, explains its functions, and provides ways to feel and engage it.
Anatomical Placement of the Latissimus Dorsi
The Latissimus Dorsi is a large, flat, triangular muscle that covers a significant portion of the back, giving the torso its characteristic width. It is a superficial muscle, situated just beneath the skin and covering many deeper muscles. Its expansive structure requires multiple anchor points, known as origins, across the lower half of the back and pelvis.
The muscle originates from a wide area of connective tissue and bone, including the lower six thoracic vertebrae and all of the lumbar vertebrae. This attachment is maintained through the thoracolumbar fascia. The muscle also connects to the posterior section of the iliac crest (the upper part of the hip bone) and typically the lower three or four ribs.
From this broad base, the muscle fibers sweep upward and converge toward the armpit area, forming a narrow, twisting tendon. This tendon inserts onto the humerus (the upper arm bone) in the floor of the intertubercular groove. This attachment to the front of the upper arm, despite the muscle’s location on the back, allows it to influence arm movement. The connection points, from the pelvis to the arm bone, show why the Latissimus Dorsi is a global mobilizer and stabilizer.
Key Roles in Upper Body Movement
The unique anatomical placement of the Latissimus Dorsi allows it to perform several distinct actions on the arm at the shoulder joint. Its primary functions involve pulling the arm toward the torso in three planes of motion. The first is shoulder adduction, the motion of bringing the arm down toward the side of the body, as seen in a pull-up or lat pulldown.
The muscle also facilitates shoulder extension, the action of pulling the arm backward behind the torso. This movement is utilized in activities like swimming strokes or rowing motions. The third main action is the internal, or medial, rotation of the shoulder, which involves turning the arm inward toward the midline of the body.
Beyond arm movement, the lats contribute to the stability of the entire torso and act as accessory muscles of respiration. When the arms are fixed overhead, such as when hanging from a bar, the lats pull the trunk upward and forward, which is their role in climbing motions. The muscle assists with both deep inhalation by expanding the rib cage and forceful exhalation.
How to Identify and Engage Your Lats
Developing an awareness of the Latissimus Dorsi is often the most challenging part of strengthening the muscle. To physically locate the muscle, place your hands on your sides just below your armpits, with your fingertips resting on the muscle tissue along the side of your ribcage. This area is where the broad muscle sheet starts to narrow before attaching to the arm.
A simple way to feel the muscle contract is to perform a gentle pulling motion, such as pulling your elbow straight back toward your hip while keeping your arm close to your body. You should feel the muscle beneath your fingers tense up and thicken during this movement. Another tactile cue involves imagining you are trying to “pinch” your armpits closed or attempting to hold an object between your arm and the side of your torso.
A common technique to increase muscle awareness involves focusing on initiating pulling motions with the elbows rather than the hands. For example, when performing a rowing motion, focus on drawing your elbows back and down toward your waist, which naturally recruits the lats. Consciously depressing the shoulders (pulling them down away from the ears) helps set the shoulder blade in a stable position that favors lat engagement. This focus helps isolate the Latissimus Dorsi, preventing other muscles like the biceps or upper trapezius from taking over.