Chapter 10 - Section 10.5 - Study Guide - Assess Your Learning Outcomes - Page 372: 10

The muscles of the superficial posterior compartment of the leg, which includes the popliteus and the triceps surae. The triceps surae consists of two primary muscles, the gastrocnemius and the soleus. These muscles are essential for plantarflexion of the foot and ankle. Additionally, we'll discuss the relationship of the triceps surae to the calcaneal tendon (Achilles tendon) and the calcaneus (heel bone). Here's an overview of these components: 1. **Popliteus:** - **Location:** The popliteus muscle is situated in the posterior compartment of the leg, deep to the gastrocnemius and soleus. - **Origin:** It originates from the lateral condyle of the femur. - **Insertion:** The muscle inserts onto the posterior surface of the tibia, near the popliteal fossa (the back of the knee joint). - **Function:** The primary function of the popliteus muscle is to unlock the knee joint by medially rotating the tibia on the femur. This action allows the knee to flex more easily and initiates the bending of the knee. 2. **Triceps Surae:** - The triceps surae is a collective term for two muscles: the gastrocnemius and the soleus. - **Gastrocnemius:** - **Location:** Gastrocnemius is the larger of the two muscles and forms the bulging calf. - **Origin:** It originates from the medial and lateral condyles of the femur. - **Insertion:** The muscle inserts onto the posterior surface of the calcaneus (heel bone) via the Achilles tendon. - **Function:** Gastrocnemius is a powerful muscle responsible for plantarflexion of the foot and ankle. It is particularly active when the knee is extended (straightened). - **Soleus:** - **Location:** Soleus is located deep to the gastrocnemius. - **Origin:** It originates from the posterior surfaces of the tibia and fibula. - **Insertion:** The muscle also inserts onto the posterior surface of the calcaneus, blending with the Achilles tendon. - **Function:** Soleus plays a crucial role in plantarflexion of the foot and ankle. It is active during activities when the knee is flexed (bent), such as during squatting or standing on tiptoes. 3. **Relationship of Triceps Surae to the Calcaneal Tendon (Achilles Tendon) and Calcaneus:** - The calcaneal tendon, commonly known as the Achilles tendon, is a strong fibrous band that connects the triceps surae (gastrocnemius and soleus muscles) to the calcaneus (heel bone). - When the triceps surae contract, they pull on the calcaneal tendon, which, in turn, exerts force on the calcaneus. This action results in plantarflexion of the foot, causing the toes to point downward and the heel to rise. - The Achilles tendon is one of the strongest tendons in the human body and is vital for activities such as walking, running, jumping, and standing on tiptoes. The muscles of the superficial posterior compartment of the leg, along with their connections to the calcaneal tendon, are essential for various lower limb movements and maintaining stability during weight-bearing activities.

The muscles of the superficial posterior compartment of the leg, which includes the popliteus and the triceps surae. The triceps surae consists of two primary muscles, the gastrocnemius and the soleus. These muscles are essential for plantarflexion of the foot and ankle. Additionally, we'll discuss the relationship of the triceps surae to the calcaneal tendon (Achilles tendon) and the calcaneus (heel bone). Here's an overview of these components: 1. **Popliteus:** - **Location:** The popliteus muscle is situated in the posterior compartment of the leg, deep to the gastrocnemius and soleus. - **Origin:** It originates from the lateral condyle of the femur. - **Insertion:** The muscle inserts onto the posterior surface of the tibia, near the popliteal fossa (the back of the knee joint). - **Function:** The primary function of the popliteus muscle is to unlock the knee joint by medially rotating the tibia on the femur. This action allows the knee to flex more easily and initiates the bending of the knee. 2. **Triceps Surae:** - The triceps surae is a collective term for two muscles: the gastrocnemius and the soleus. - **Gastrocnemius:** - **Location:** Gastrocnemius is the larger of the two muscles and forms the bulging calf. - **Origin:** It originates from the medial and lateral condyles of the femur. - **Insertion:** The muscle inserts onto the posterior surface of the calcaneus (heel bone) via the Achilles tendon. - **Function:** Gastrocnemius is a powerful muscle responsible for plantarflexion of the foot and ankle. It is particularly active when the knee is extended (straightened). - **Soleus:** - **Location:** Soleus is located deep to the gastrocnemius. - **Origin:** It originates from the posterior surfaces of the tibia and fibula. - **Insertion:** The muscle also inserts onto the posterior surface of the calcaneus, blending with the Achilles tendon. - **Function:** Soleus plays a crucial role in plantarflexion of the foot and ankle. It is active during activities when the knee is flexed (bent), such as during squatting or standing on tiptoes. 3. **Relationship of Triceps Surae to the Calcaneal Tendon (Achilles Tendon) and Calcaneus:** - The calcaneal tendon, commonly known as the Achilles tendon, is a strong fibrous band that connects the triceps surae (gastrocnemius and soleus muscles) to the calcaneus (heel bone). - When the triceps surae contract, they pull on the calcaneal tendon, which, in turn, exerts force on the calcaneus. This action results in plantarflexion of the foot, causing the toes to point downward and the heel to rise. - The Achilles tendon is one of the strongest tendons in the human body and is vital for activities such as walking, running, jumping, and standing on tiptoes. The muscles of the superficial posterior compartment of the leg, along with their connections to the calcaneal tendon, are essential for various lower limb movements and maintaining stability during weight-bearing activities.