Semitendinosus Anatomy: Origin, Insertion, Action, Innervation

Semitendinosus: Origin, Insertion, Action, Innervation

Origin: Upper, inner quadrant of the posterior surface of the ischial tuberosity, conjoined with the long head of biceps femoris
Insertion:Upper part of the medial surface of the tibia, behind the attachment of sartorius and distal and slightly anterior to the attachment of gracilis
Actions: Extension of the thigh at the hip, Flexion of the leg at the knee, Internal rotation of the leg at the knee
Innervation: Tibial portion of the sciatic nerve (L5, S1, S2)
Blood Supply:Branches from the internal iliac, popliteal, and profunda femoris arteries Semit_muscle_md

Semitendinosus Actions With Agonists and Antagonists

Primary Actions of the Adductor Brevis

1. Extension of the thigh at the hip


  • Gluteus maximus
  • Semimembranosus
  • Biceps femoris (long head)
  • Adductor magnus (posterior)


  • Psoas major
  • Iliacus
2. Flexion of the leg at the knee


  • Biceps femoris
  • Semimembranosus


  • Vastus Lateralis
  • Vastus Medialis
  • Vastus Intermedius
  • Rectus Femoris

Gracilis, sartorius, popliteus, gastrocnemius, and plantaris assist with flexion of the knee

3. Internal rotation of the leg at the knee


  • Semimembranosus
  • Popliteus


  • Biceps femoris

Sartorius and gracilis assist with internal rotation of knee

For more information see: 

Semitendinosus Muscle Pain


Recommended Anatomy Books:

Anatomy Coloring Book

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 how the act of coloring will help with recall. But this is not just a beginners 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.

Human Muscle Anatomy

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!

Basic Clinical Massage Therapy

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.

Muscle Anatomy Flashcards

Musculoskeletal Anatomy Flashcards Are you a student or professional therapist who needs to brush up on the musculoskeletal system? Dr. Joseph E. Muscolino DC has developed a comprehensive set of flashcards that will help develop a mind’s picture of exactly where the muscles lie under the skin. A highly recommended study aid for students. Great for non students who want an easy comprehensive anatomy guide.