What does the Achilles tendon connect?

The Achilles tendon is a strong fibrous cord that connects the gastrocnemius and soleus muscles of the calf to the heel bone (calcaneus). This connection is crucial for enabling movements such as walking, running, and jumping, as it facilitates the ability to push off from the ground. When the calf muscles contract, the Achilles tendon pulls on the heel, allowing for plantar flexion of the foot.

The other options describe connections involving different muscles and tendons. For instance, the quadriceps femoris does not connect to the knee via the Achilles tendon; instead, it connects to the patellar tendon which influences knee movement. The biceps muscle connects to the forearm through other tendons, not the Achilles tendon. Additionally, the pectoralis major is a muscle that connects to the shoulder, but it is unrelated to the Achilles tendon. Therefore, the correct choice accurately represents the anatomical and functional connection provided by the Achilles tendon.