Semimembranosus Muscle Anatomy

Overview
Origin Ischial tuberosity
Insertion Medial condyle of the tibia
Action Flexes knee
Extends the hip
Medially rotates tibia when knee is flexed
Nerve Tibial nerve of the sciatic plexus (L5, S1 and S2)
Artery Profunda femoris and gluteal arteries

Location & Overview

The semimembranosus muscle is located on the posterior and medial aspects of the thigh. It is one of the three hamstring muscles. The other two hamstring muscles are the biceps femoris muscle and the semitendinosus muscle. The semimembranosus muscle is the most medial of these three hamstring muscles. It is mostly covered by the semitendinosus muscle but the semimembranosus is a much flatter and wider shaped muscle. The semimembranosus muscle also shares relatively close origin and insertion points with the semitendinosus [1].

Semimembranosus muscle in isolation

Pictured here is the semimembranosus muscle in isolation.

semimembranosus muscle in isolation from a superficial view

Pictured here is the semimembranosus muscle in isolation from a superficial view.

hamstring muscles from a superficial view

Pictured here are the hamstring muscles from a superficial view. The semimembranosus muscle is one of the three hamstring muscles.

Origin & Insertion

The semimembranosus originates at the ischial tuberosity and inserts on the medial condyle of the tibia [2] [3].

origin of the semimembranosus muscle marked in red

Pictured here is the origin of the semimembranosus muscle marked in red. It originates on the ischial tuberosity.

distal tendon of the semimembranosus muscle

Pictured here is the distal tendon of the semimembranosus muscle where it inserts on the medial condyle of the tibia.

insertion of the semimembranosus muscle marked in blue

Pictured here is the insertion of the semimembranosus muscle marked in blue on the medial condyle of the tibia.

Actions

The semimembranosus muscle is able to flex the knee joint, extend the hip and internally/medially rotate the knee when the joint is flexed [4] [5].

Innervation

The semimembranosus muscle is innervated by the tibial nerve of the sciatic plexus (L5, S1 and S2)[6].

Blood Supply

Blood is supplied to the semimembranosus muscle by the profunda femoris and gluteal arteries [7].

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Semimembranosus Muscle Flashcards

References

References
1, 6 Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.
2, 4 Rodgers CD, Raja A. Anatomy, Bony Pelvis and Lower Limb, Hamstring Muscle. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546688/
3, 5 Afonso J, Rocha-Rodrigues S, Clemente FM, et al. The Hamstrings: Anatomic and Physiologic Variations and Their Potential Relationships With Injury Risk. Front Physiol. 2021;12:694604. Published 2021 Jul 7. doi:10.3389/fphys.2021.694604
7 Tomaszewski KA, Henry BM, Vikse J, Pękala P, Roy J, Svensen M, Guay D, Hsieh WC, Loukas M, Walocha JA. Variations in the origin of the deep femoral artery: A meta-analysis. Clin Anat. 2017 Jan;30(1):106-113. doi: 10.1002/ca.22691. Epub 2016 Feb 2. PMID: 26780216.