Lat anatomy at a glance
| Feature | Detail |
|---|---|
| Attaches to the trunk at | Lower thoracic spinous processes (about T7 to T12), the thoracolumbar fascia that links to the lumbar spine and sacrum, the back of the iliac crest, the lower three to four ribs, and the inferior angle of the shoulder blade |
| Attaches to the arm at | The floor of the intertubercular groove of the humerus (upper arm bone) |
| Nerve supply | Thoracodorsal nerve (roots C6 to C8, mostly C7) |
| Main shoulder actions | Extension, adduction, internal (medial) rotation |
Anatomical details vary between textbooks, particularly the exact number of vertebrae and ribs. The values above follow the StatPearls anatomy review (Anatomy, Back, Latissimus Dorsi).
Latissimus dorsi anatomy: how the muscle is built
The name means "broadest muscle of the back." Its fibers fan out from a wide area along the spine and pelvis, then narrow and wind around the teres major muscle before forming a flat tendon on the front of the humerus. The upper fibers run nearly horizontally and the lower fibers run more vertically, which is one reason the lats can contribute across different arm positions.
Secondary roles
The lats are also active during deep breathing, coughing, and sneezing. Because they attach to the spine and pelvis, researchers have studied whether they also help move the trunk, but the evidence on their effect on spine extension, side bending, or rotation is mixed, so don't think of them as a core exercise.
The shoulder movements the lats control
Shoulder extension: the arm moves back
Extension moves the upper arm backward relative to your torso, the way your arm travels in a row or when you push a straight arm down and behind you. The lats work with the teres major here. The motion is strongest when it starts from a position where the arm is partly raised in front of you or out to the side.
Shoulder adduction: the arm moves toward your side
Adduction brings the arm toward your body's midline. In a pull-up or pulldown, your arms start overhead and travel down toward your sides, so the lats combine adduction with extension. Internal rotation can join in, which is one reason a single rep involves more than one action.
Why the pull-up looks different from the pulldown
In a pulldown, the bar moves and your torso stays mostly in place. In a pull-up, your hands are fixed overhead, so the same muscle action moves your trunk up and forward instead. The lats are doing the same kind of work either way; the load just moves a different part.
Shoulder movement vs. elbow movement in pulling exercises
Pulling exercises use two joints. The lats move the upper arm at the shoulder, while the biceps brachii, brachialis, and brachioradialis bend the elbow. The lats do not bend the elbow. Other muscles assist too; NASM lists the biceps, brachialis, rear deltoids, rhomboids, trapezius, and teres major as helpers in the lat pulldown (NASM).
| Exercise | Shoulder action | Elbow action | When to choose it |
|---|---|---|---|
| Straight-arm pulldown | Extension from a raised position | Little to none | You want to feel the shoulder movement without the elbow bending. |
| Row | Extension (arm moves back toward the torso) | Bends | You want a horizontal pull that also works the mid-back. |
| Lat pulldown | Adduction with extension | Bends | You want a vertical pull with an adjustable load. |
| Pull-up | Adduction with extension, moving the body | Bends | You can lift your body weight through a full range of motion. |
How to choose and perform lat exercises
- Start with the arm path. Ask which direction your upper arm travels. Down from overhead means a pulldown or pull-up. Back toward your torso means a row or straight-arm pulldown.
- Don't worry much about grip width. A 2025 electromyography study of seven pulldown variations found no significant differences in lat muscle activation across the grips tested, and an earlier study of grip width reported no major difference in lat activation either (Calcagno and Fiorilli, 2025). Pick the grip that is comfortable for your shoulders and wrists.
- Lean back slightly on pulldowns. NASM suggests about 20 to 30 degrees to match the machine's line of pull to the lats.
- Keep your torso steady. If you need to swing or rock to finish the rep, reduce the weight so the shoulder and back do the work.
- Use a full range of motion, especially at the stretched position. In an 8-week study of 30 resistance-trained adults, training the upper body with lengthened partial reps produced similar results to full-range reps for arm muscle growth and lat-pulldown strength-endurance (Wolf et al., PeerJ, 2025). The study didn't measure lat size directly, so it supports emphasizing the stretched position rather than ruling out full range.
If you arch to get your arms overhead
If your lower back arches and your ribs flare whenever you raise your arms, tight or short lats may be one contributor. Anatomy references note that shortened lats can make the back extend and rotate during overhead reaching. Keep your ribs down while you reach, and see a physical therapist if overhead movement is painful or restricted.
FAQ
Is the lat pulldown a good substitute for pull-ups?
Do the lats help with breathing?
Why do my biceps get tired before my back on pulling exercises?
Bottom line
The lats link your spine, pelvis, and ribs to your upper arm, and they drive extension, adduction, and internal rotation of the shoulder. Choose exercises by the path your arm takes, remember that your elbow and other back muscles help, and don't expect a specific grip to isolate the lats.
References
- StatPearls: Anatomy, Back, Latissimus Dorsi
- StatPearls: Anatomy, Thorax, Thoracodorsal Nerves
- NASM: The Biomechanics of the Lat Pulldown
- Calcagno G, Fiorilli G. EMG analysis of back muscle activation during lat pulldown: grip variations and forearm orientation (2025)
- Wolf M et al. Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions (PeerJ, 2025)
This article is general education, not medical advice. See a clinician if you have persistent shoulder, back, or arm pain.
