Final answer:
The triceps surae is a group of muscles consisting of the gastrocnemius, soleus, and plantaris, which are located in the superficial posterior compartment of the leg and function mainly in plantar flexion of the foot.
Step-by-step explanation:
The triceps surae is composed of the gastrocnemius, soleus, and plantaris muscles. These muscles collectively insert onto the calcaneal tendon (Achilles tendon) and are primarily involved in plantar flexion of the foot. Gastrocnemius is the most superficial and visible muscle of the calf, which assists in plantar flexion of the foot at the ankle when the knee is extended. The soleus is a large, flat muscle deep to the gastrocnemius, and it also aids in plantar flexion, but acts regardless of the position of the knee.
The plantaris muscle runs obliquely between the gastrocnemius and the soleus, though it is not present in all individuals. Importantly, other muscles such as the tibialis anterior, flexor hallucis longus, extensor hallucis longus, and fibularis muscles are part of different compartments in the leg and are not included in the triceps surae.