Muscle
Latissimus dorsi
Broad climbing/swimming muscle
High-yield
Powerful arm adductor/extensor/medial rotator - "handcuff muscle." Innervated by the thoracodorsal nerve (C6-C8).
Overview
The largest muscle of the back, spanning from the lower trunk to the humerus. It is the prime extensor and adductor of the arm from a flexed position.
Reference facts
- Origin
- Spinous processes of T7-T12, thoracolumbar fascia (through which it reaches the lumbar and sacral spines), iliac crest, inferior 3-4 ribs, and often the inferior angle of the scapula
- Insertion
- Floor of the intertubercular (bicipital) groove of the humerus
- Action
- Extends, adducts, and medially rotates the humerus; raises the body toward the arms in climbing
- Innervation
- Thoracodorsal nerve (C6, C7, C8)
- Blood supply
- Thoracodorsal artery
Mnemonic
Thoracodorsal: "ladies between two majors" (latissimus dorsi between teres major and pectoralis major functionally).
Frequently asked questions
What does the latissimus dorsi do?
The latissimus dorsi extends, adducts, and medially rotates the humerus; raises the body toward the arms in climbing.
What nerve innervates the latissimus dorsi?
The latissimus dorsi is innervated by the thoracodorsal nerve (C6, C7, C8).
Where does the latissimus dorsi attach?
The latissimus dorsi originates from the spinous processes of T7-T12, thoracolumbar fascia (through which it reaches the lumbar and sacral spines), iliac crest, inferior 3-4 ribs, and often the inferior angle of the scapula and inserts on the floor of the intertubercular (bicipital) groove of the humerus.
What is the blood supply of the latissimus dorsi?
The latissimus dorsi is supplied by the thoracodorsal artery.