Questions and Answers
What are the muscles in the posterior compartment of the thigh?
Biceps femoris, semitendinosus, semimembranosus
What are the characteristics of the posterior compartment muscles?
Also known as hamstrings, it flexes the knee and extends the thigh. Can also rotate the knee. Innervated by the tibial division of the sciatic nerve. Supplied by the deep (femoral) artery of the thigh and the femoral artery.
What is the origin of the semitendinosus?
The semitendinosus originates at the ischial tuberosity.
Where does the semitendinosus insert?
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What innervates the semitendinosus?
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What action does the semitendinosus perform?
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What is the origin of the semimembranosus?
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Where does the semimembranosus insert?
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What innervates the semimembranosus?
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What action does the semimembranosus perform?
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What is the origin of the biceps femoris?
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What is the insertion for the biceps femoris?
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What innervates the biceps femoris?
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What action does the biceps femoris perform?
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Talk about hamstring injuries.
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Compare the functions of the anterior compartment, medial compartment, and posterior compartments.
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Study Notes
Posterior Compartment of Thigh
- Consists of three primary muscles: biceps femoris, semitendinosus, and semimembranosus.
- Collectively referred to as the hamstrings, responsible for knee flexion and thigh extension.
- Innervated by the tibial division of the sciatic nerve.
- Blood supply comes from the deep femoral artery and the femoral artery.
Semitendinosus Muscle
- Originates from the ischial tuberosity.
- Inserts at the medial surface of the superior part of the tibia.
- Innervated by the tibial division of the sciatic nerve.
- Actions include extending the thigh, flexing the leg, and medially rotating the leg.
Semimembranosus Muscle
- Also originates from the ischial tuberosity.
- Inserts into the posterior part of the medial condyle of the tibia.
- Innervated by the tibial division of the sciatic nerve.
- Functions similarly to the semitendinosus, extending the thigh, flexing the leg, and medially rotating it.
Biceps Femoris Muscle
- Originates from the ischial tuberosity and the linea aspera of the femur, including the lateral supracondylar line.
- Inserts on the lateral side of the head of the fibula.
- Innervated by both the tibial and common fibular divisions of the sciatic nerve.
- Responsible for knee flexion, lateral rotation of the leg, and thigh extension.
Hamstring Injuries
- Commonly occur at the proximal myotendinous junction, particularly in the biceps femoris.
- Injuries typically do not happen within the tendon itself.
- Can include bony avulsions at the ischial origin, often linked to sudden, high-force hip-flexion injuries.
Comparative Muscle Functions
- Anterior compartment primarily flexes the thigh.
- Medial compartment primarily extends the leg.
- Posterior compartment extends the thigh while flexing the leg.
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Description
Test your knowledge on the posterior compartment of the thigh, focusing on the biceps femoris, semitendinosus, and semimembranosus muscles. This quiz covers their characteristics, functions, and innervation. Perfect for anatomy students and enthusiasts!