The sciatic nerve is a very thick nerve trunk in the posterior aspect of the lower extremity and is responsible for the transmission of sensory functions in the hip, posterior thigh, calf, and foot, and for innervating the muscles involved in these areas to perform the corresponding activities. The sciatic nerve begins at the inferior border of the pear-shaped muscle and then passes deep into the gluteus maximus to reach the posterior aspect of the hip joint, between the greater trochanter and the sciatic tuberosity, and then follows the long axis of the midpoint of the posterior thigh. The patient can simply locate it: that is, deep in the posterior lateral muscles of the hip, after which it travels down the midline of the posterior thigh. In the popliteal fossa, which is the posterior aspect of the knee, it is divided into the tibial and common peroneal nerves, which conduct down the inner and outer sides of the popliteal fossa, respectively, and its endings reach the foot. Once the sciatic nerve is stimulated by cold, compression and inflammation, it will cause sciatica and sciatica, whose main symptoms are radiating pain, numbness and weakness in the thigh, foot and calf.