Upper BackSource-checked

Latissimus dorsi

Pronunciation: lah-TISS-ih-mus DOR-sy

Simplified back view showing the diamond-shaped trapezius over the upper back and neck, the rhomboids between the shoulder blades, and the broad latissimus dorsi fanning up from the lower back. — Upper back — trapezius, rhomboids, and latissimus dorsi (simplified). A beginner-level schematic of the major upper-back muscles: trapezius, rhomboids, and latissimus dorsi.
Illustration: Anatomy Learning Platform (original) · CC0-1.0 (public domain dedication)

For beginners

Nicknamed the 'lats', this large muscle gives the back its V-shape. It pulls your arm down toward your body and behind you, which is why it powers pull-ups and pulldowns.

Show the advanced explanation

Because it spans from the pelvis and spine to the humerus, it links the arm to the trunk and contributes to trunk stability and even forced expiration; tightness can limit overhead reach.

Structure & function

Location: The broad muscle of the mid and lower back that fans up to the arm.
Origin: Lower thoracic and lumbar vertebrae, the sacrum, and the iliac crest (via a broad sheet of connective tissue).
Insertion: Intertubercular (bicipital) groove of the humerus.
Main action(s): Extends, adducts, and internally rotates the arm at the shoulder — powerfully pulling the arm down and back.
Joint(s) crossed: Glenohumeral joint
Movement plane: multiple
Innervation: Thoracodorsal nerve (C6–C8)
In daily movement: Pulling movements — climbing, pulling a door closed, pushing up out of a chair.
In exercise: Prime mover in pull-ups, lat pulldowns, and rows; the biggest muscle of the back.
Commonly confused with: Confused with the teres major (a smaller muscle with a similar action, nicknamed 'lat's little helper').
Common misconceptions: Pulldowns/pull-ups are compound — the lats work with the biceps, rear delts, and mid-back, not alone.

Exercises that use this muscle

As a primary mover

⚠ Safety note

Very heavy overhead pulling with poor control can stress the shoulder; build range and strength gradually.

Sources

“The latissimus dorsi extends, adducts, and medially rotates the humerus.”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.5 Muscles of the Pectoral Girdle and Upper Limbs

Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19

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