| Serratus dorsalis superior | Origin - First nine ribs. Insertion - Mid-dorsal raphe. Action - Draws ribs crainially. |
| Serratus dorsalis inferior | Origin - Last four ribs. Insertion - Lumbar spinous process. Action - Draws ribs crainially. |
| Spinalis dorsi | Origin - Last four thoracic vertebrae. Insertion - Thoraco-cervical vertebrae. Action - Extends vertebral column. |
| Longissimus dorsi | Origin - Sacral and caudal vertebrae. Insertion - Trunk and cervical vertebrae. Action - Extends vertebral column. |
| iliocostalis | Origin - As separate muscle bundles from lower thoracic ribs. Insertion - Three ribs craniad to the origin of each bundle. Action - Draws ribs together. |