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Quadratus Lumborum: Origin, Insertion, Action, Innervation

Origin: Iliolumbar ligaments and the iliac crest
Insertion: Inferior border of the 12th rib and the transverse processes of L1, L2, L3, L4 vertebra
Actions: Unilaterally: Lateral flexion of the spine, elevation of the pelvis
Bilaterally: Depresses the 12th rib at the costospinal joints
Innervation: Ventral Primary rami of (T7 to T12)
Blood Supply: Lumbar branch of the iliolumbar artery

Quadratus Lumborum Muscle Origin, Insertion, Action, Innervation
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Quadratus Lumborum Actions With Agonists and Antagonists

Primary Actions of the Quadratus Lumborum

1. Lateral rotation of the lumbar spine when acting unilaterally

  Agonists: 

  • Iliocostalis lumborum
  • Longissimus thoracis
  • Psoas major
  • External oblique
  • Internal oblique

  Antagonists: Same muscles on contralateral side

  • Iliocostalis lumborum
  • Longissimus thoracis
  • Psoas major
  • External oblique
  • Internal oblique

Secondary Actions of the Quadratus Lumborum:

1. Elevation of the pelvis when acting unilaterally

  Agonists:

  • Rectus abdominis
  • Internal oblique
  • External oblique

  Antagonists:  None

2. Assists in forced exhalation by fixing the 12th rib, facilitating contraction of the diaphragm

Recommended Anatomy Books:

The Anatomy Coloring Book is one of the best study and reference books for beginning anatomy students. The diagrams are clearly labeled and allow you to see the relationship and placement of the various structures of the body. You will also be surprised at how the act of coloring will help with recall. But this is not just a beginner's book, it is also great for practitioners and therapists to have on hand to use with clients and patients to use as a visual reference.

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 layperson who wants to gain an understanding of the muscle, skeletal system and how our bodies move. This book will not disappoint!

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 the recommended treatments for each muscle.

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