What is the tendon below knee cap called?

The tendon below the kneecap is called the patellar tendon. It is a thick, fibrous cord of tissue that connects the kneecap (patella) to the shinbone (tibia). The patellar tendon is responsible for transmitting the force of the quadriceps muscles, which are located on the front of the thigh, to the shinbone, allowing the knee to extend.