longissimus thoracis (musculus longissimus dorsi)

Origin

• transverse processes of lower thoracic vertebrae (with iliocostalis thoracis)

Insertion

• lateral fibers: into most or all of the ribs between angles & tubercles & into tips of transverse processes of the upper lumbar vertebrae
• medial fibers: into accessory processes of upper lumbar vertebrae & transverse processes of thoracic vertebrae

Action

extends lumbar & thoracic vertebrae

Innervation

• dorsal rami of thoracic & lumbar spinal nerves

More general terms

• erector spinae (musculus sacrospinalis)