How much do you know about the posterior leg muscles and their actions?

Study Notes

The text describes the anatomy and actions of the superficial group of posterior leg muscles.
The group includes the gastrocnemius, soleus, and plantaris muscles.
The gastrocnemius is a flexor of the knee and ankle joint, while the soleus is a strong but slow plantar flexor of the ankle joint.
The plantaris muscle has a negligible action compared to the other two muscles.
The triceps surae muscles can act alone and are responsible for plantar flexion of the foot against resistance.
The calcaneal tendon and triceps surae can be seen and palpated during testing.
The lateral head of the gastrocnemius originates from the lateral aspect of the lateral condyle of the femur, while the medial head originates from the popliteal surface of the femur.
The insertion of the gastrocnemius and soleus muscles is the posterior surface of the calcaneus via the calcaneal tendon.
The triceps surae muscles are innervated by the tibial nerve (S1, S2).
The gastrocnemius bellies provide the necessary rapid contraction required for propulsion in fast walking, running, and leaping.