- Origin
- Spinous processes of T7–T12
- Thoracolumbar fascia
- Iliac crest
- Inferior 3 to 4 ribs
- Sometimes from the inferior angle of the scapula
- Insertion
- Floor of the intertubercular sulcus (bicipital groove) of the humerus
- Innervation
- Thoracodorsal nerve (C6–C8), from the posterior cord of the brachial plexus
- Blood Supply
- Thoracodorsal Artery (branch of the subscapular artery)
- Actions
- Extends, adducts, and medially rotates the humerus
- Assists in pulling the trunk upward during climbing or using crutches
- Plays a role in forced expiration (e.g. coughing)
