(superficial muscle of the back)
- O: Iliac crest, Thoraco-lumbar (T/L) fascia, SP's of last 6 thoracic vertebrae and last 3-4 ribs
- F.D: superior lateral
- Insertion: Floor of the intertubercular groove
- Action: Extension, adduction and medial rotation of the humerus
- Nerve: Thoracodorsal nerve
- Special: Broadest muscle of the back
O and I switch then the action is that the body raises towards the arms (chin up).Thin, superficial and ascends the side of the trunk.