The latissimus dorsi is the largest muscle in your upper body, and its primary job is moving your arms downward and behind you. It pulls your upper arm toward your torso, rotates it inward, and extends it behind your body. But it does more than move your arms. The lats also stabilize your spine, assist with breathing during intense effort, and connect your shoulder to your opposite hip through a sheet of connective tissue along your lower back.
Where the Muscle Sits
The latissimus dorsi is a broad, flat muscle that spans most of your back. It originates from the lower six vertebrae of your mid-back, the thick connective tissue covering your lower spine (the thoracolumbar fascia), the top of your pelvis, and the bottom three or four ribs. From this wide base, the muscle fibers converge and twist into a narrow tendon that attaches to the front of your upper arm bone, just below the shoulder joint.
This sweeping origin is what gives the muscle its characteristic V-shape when well developed. It’s also why the lats influence so many different movements: the fibers pull from multiple angles depending on where your arm is positioned.
How It Moves Your Arms
The latissimus dorsi performs several distinct actions at the shoulder joint:
- Extension: pulling your arm backward, like the downward stroke of a swimming pull or the follow-through of a row
- Adduction: bringing your arm down toward your side from a raised position, as in a pull-up or lat pulldown
- Internal rotation: turning your upper arm inward, the way your hand moves when you reach behind your back
- Horizontal abduction: pulling your arm outward when it’s raised to shoulder height
The muscle also draws your shoulder blade downward and inward. This is why you feel your lats engage not just during pulling exercises but any time you depress your shoulders, like pushing yourself up from an armchair or stabilizing on parallel bars.
Spine and Hip Stability
Because the lats attach to your lower spine and pelvis, they play a significant role in trunk stability that goes well beyond arm movement. The muscle connects to the thoracolumbar fascia, a dense sheet of tissue that also anchors the gluteus maximus on the opposite side of your body. This creates a diagonal sling from one shoulder to the opposite hip.
Research on this connection has found that contracting the latissimus dorsi increases lumbar stiffness and even changes the resting position of the opposite hip, rotating it outward and increasing its passive stiffness. In practical terms, this means your lats help brace your spine during walking, running, and lifting. When you swing your right arm back during a stride, your left glute fires simultaneously, and the thoracolumbar fascia transfers force between them. Weak or tight lats can disrupt this force transfer and contribute to lower back issues.
Its Role in Breathing
The latissimus dorsi is classified as an accessory muscle of respiration. During normal, quiet breathing it stays mostly silent. But it activates during very deep inhalations, when you inhale against resistance, and when you need to expel air forcefully, like during a hard cough or a maximal effort lift where you brace your core.
This respiratory role is especially visible in trained singers. Studies of classical vocalists found that the lats engage during supported singing to help maintain an expanded rib cage. During loud, projected phrases near the end of an aria, the latissimus dorsi fires alongside neck muscles to control airflow and thoracic pressure simultaneously. If you’ve ever felt your sides engage during a forceful exhale or sustained yell, that’s your lats contributing.
Exercises That Target the Lats
Any movement that involves pulling something toward your body or pulling your body toward something will recruit the latissimus dorsi heavily. Pull-ups, chin-ups, rows, and lat pulldowns are the primary exercises. Swimming, rock climbing, and kayaking are sports that demand constant lat engagement.
A common question is whether grip width matters for lat activation during pulldowns. A study published in the Journal of Strength and Conditioning Research tested narrow, medium, and wide grips and found that overall lat muscle activation was similar across all three widths. However, participants could lift more weight with narrow and medium grips (about 80 kg) compared to wide grip (about 77 kg). So while the lats work equally hard regardless of grip width, a narrower grip lets you handle heavier loads, which can matter for progressive overload in training.
Common Injuries and Symptoms
Latissimus dorsi strains typically happen during sudden, forceful contractions (the explosive phase of a heavy pull-up or rowing stroke) or from repetitive overhead motions in swimming and climbing. Poor exercise form, inadequate warm-up, and muscle fatigue all raise the risk. A previous lat strain also makes the muscle more vulnerable to re-injury.
Strains are graded by severity. A mild (grade 1) strain involves minor fiber tearing with some tenderness but minimal strength loss. A moderate (grade 2) strain means partial tearing with noticeable pain, swelling, and reduced strength. A severe (grade 3) strain is a complete rupture with significant swelling and substantial loss of function. You’ll typically feel the pain along the side or back of your torso, and it often worsens when reaching overhead, pulling, or rotating your trunk.
Recovery follows a general timeline: rest and pain management for the first 72 hours, progressive strengthening exercises from about two to eight weeks, and a return to full activity after eight weeks or more. Mild strains recover faster, while complete ruptures may require imaging and sometimes surgical repair. Rehabilitation almost always includes core strengthening, since the lats work in concert with your trunk muscles and returning to activity with a weak core puts the muscle at risk again.
Surgical Uses of the Muscle
The latissimus dorsi’s size, reliable blood supply, and relative expendability make it one of the most commonly used muscles in reconstructive surgery. In breast reconstruction after mastectomy, surgeons can transfer the lat muscle along with its overlying skin and fat to the chest wall. This is called a latissimus dorsi flap. Because most women don’t have enough back tissue to fully recreate a breast mound, an implant or tissue expander is usually placed beneath the transferred muscle.
The same flap technique is used to fill defects after breast-conserving surgery when removal of tissue leaves a misshapen area. Beyond breast reconstruction, lat flaps are used to cover wounds on the chest wall, repair shoulder defects, and restore elbow flexion in patients with nerve injuries. The nerve that controls the lat, the thoracodorsal nerve, is also notable because it often survives even severe injuries to the brachial plexus (the nerve network running from your neck to your arm), making it a useful donor nerve for transfer procedures that restore function elsewhere in the arm.