Serratus posterior inferior (muscle)

[TA] lower intermediate muscle of back; origin, with latissimus dorsi, from spinous processes of two lower thoracic and two upper lumbar vertebrae; insertion, into lower borders of last four ribs; action, draws lower ribs backward and downward; nerve supply, ninth to twelfth intercostal. SYN: musculus serratus posterior inferior [TA], inferior posterior serratus muscle.