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