The latissimus dorsi is the broadest muscle, covering most of the posterior thorax. Its thoracodorsal nerve and artery pedicle make it the most reliable pedicled and free muscle flap donor in reconstructive surgery.
| Origin | Spinous processes of T7-T12, thoracolumbar fascia, iliac crest, lower 3-4 ribs, and occasionally the inferior scapular angle |
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| Insertion | Floor of the bicipital groove (intertubercular sulcus) of the humerus |
| Nerve Supply | Thoracodorsal nerve (C6, C7, C8) |
| Blood Supply | Thoracodorsal artery from the subscapular artery system |
| Actions | Adducts the humerus; Medially rotates the humerus; Extends the shoulder; Powers the pull-up and rowing motions; Assists respiration as an accessory expiratory muscle |
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The latissimus dorsi musculocutaneous flap is used for breast reconstruction (LD flap), axillary lymph oedema treatment, shoulder and elbow reconstruction, and scalp coverage. In shoulder tendon transfer for rotator cuff deficiency, LD is transferred to the greater tuberosity to restore external rotation. Latissimus harvest causes measurable loss of internal rotation strength but minimal functional impact in most patients.
Palpated on the posterior lateral thorax as the dominant lower back/flank muscle during resisted shoulder extension and adduction.
Pedicled LD musculocutaneous flap providing muscle and skin for post-mastectomy breast mound reconstruction, with the thoracodorsal pedicle as the reliable vascular supply.
