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Iliocostalis Thoracis Anatomy: Origin, Insertion, Actions, Innervation

Iliocostalis Thoracis Anatomy Study:Iliocostalis thoracis is also known as the iliocostalis dorsi

Iliocostalis Thoracis AnatomyOrigin: Superior borders of the angles of the lower six ribs, medial to the proximal tendon of the iliocostalis lumborum
Insertion: Superior borders of the angles of the upper six ribs and the posterior aspect of the transverse process of C7
Action: Extension of the thoracic spine, lateral flexion of the thoracic spine
Innervation: Dorsal primary rami of T1 to T12
Blood Supply: Dorsal rami of the posterior intercostal arteries



Primary Actions of the Iliocostalis Thoracis:

1. Extension of the thoracic spine when acting bilaterally

  • Agonists: Iliocostalis Cervicis, Iliocostalis Lumborum, Longissimus Cervicis, Spinalis Thoracis, Semispinalis Cervicis, Semispinalis Thoracis
  • Antagonists: Rectus abdominis

2. Lateral flexion of the thoracic spine when acting unilaterally

  • Agonists: Iliocostalis Cervicis,  Iliocostalis Lumborum, Longissimus Cervicis, External Oblique, Internal Oblique
  • Antagonists: Iliocostalis Cervicis, Iliocostalis Thoracis, Iliocostalis Lumborum, Longissimus Cervicis, External Oblique, Internal Obliqueon the opposite side

For more information: Iliocostalis Thoracis Muscle: Back, Chest and Lower Abdominal Pain

Recommended Anatomy Books

Out of the scores of books in my office Basic Clinical Massage Therapy is by far the most referenced book in my library. The musculoskeletal system is overlaid on human models allowing you to learn the precise location, origin and insertions of each muscle. The models are pictured in various poses throughout the book which also helps you visualize muscles in motion and their actions relationship with the skeletal structure and other muscles. Though it is written for massage therapists, it is an excellent book for anyone who wants to learn about the muscular system. MT’s will benefit from recommended treatments for each muscle.

Trail Guide To The Body


The Trail Guide To The Body is another excellent book to help you learn the musculature of the human body. Though the book is geared toward massage therapists and physical therapist assistants, the book with its illustrations and text helps anyone gain a thorough understanding of the human musculoskeletal system and movement. I highly recommend this book for anyone studying anatomy and believe that MTs, PTAs, and teachers of body movements should have this book in their possession. I also highly recommend this book for the lay person who wants to gain understanding of the muscle, skeletal system and how our bodies move.  This book will not disappoint!


The Trigger Point Therapy Workbook – Claire Davies, Amber Davies, and David G. Simons

Basic Clinical Massage Therapy: Integrating Anatomy and Treatment – James H. Clay and David M. Pounds

Trigger Point Therapy for Myofascial Pain – Donna Finando and Steven Finando

Massage Therapy Principles and Practice – Susan Salvo

Theory & Practice of Therapeutic Massage – Mark Beck

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