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Semimembranosus Anatomy: Origin, Insertion, Action, Innervation

Semimembranosus Anatomy Study

Semimembranosus Anatomy

Origin: Upper outer quadrant of the posterior surface of the ischial tuberosity, deep to the conjoined tendon of the semitendinosus and the long head of the biceps femoris.
Insertion: The posterior aspect of the medial condyle of tibia, below the joint line, sending fibers into the fascia over popliteal ligament.
Action: Extension of the thigh at the hip, flexion of the leg at the knee, internal rotation of the knee when knee is flexed
Innervation: Tibial portion of the sciatic nerve  (L5, S1 – 2)
Blood Supply:  Branches from the internal iliac, popliteal, and profunda femoris artery.


  • Prime Movers: Gluteus maximus, Adductor magnus (posterior part)
  • Accessory Movers: Semitendinosus, Biceps femoris (long head), Gluteus medius, Piriformis

Antagonist: Iliopsoas, Pectineus, Tensor fasciae latae, Adductor brevis, Sartorius


Primary Actions of the Semimembranosus:

1. Extension of the thigh at the hip

    • Agonists: Gluteus maximus, Semitendinosus, Biceps femoris (long head) Adductor magnus (posterior part)
    • Antagonists: Psoas major, Iliacus

2. Flexion of the leg at the knee

    • Agonist: Biceps femoris, Semitendinosus
    • Antagonists: Vastus Lateralis, Vastus Medialis, Vastus Intermedius, Rectus Femoris

3. Internal rotation of the leg at the knee

    • Agonists: Semitendinosus, Popliteus
    • Antagonists: Biceps femoris

For pain and symptom information see: Semimembranosus Muscle Buttock, Thigh and Knee Pain

Learn Anatomy With These Books

Musculoskeletal Anatomy Flashcards Musculoskeletal 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.   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.




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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