The pear-shaped muscle starts from the anterior side of the sacral foramen 2-5 and ends at the greater trochanter of the femur. The pear muscle has the function of abduction, external rotation and posterior extension of the lower limb. The pear muscle passes through the foramen magnum and the sciatic nerve passes medially, and the pear muscle tension test is mainly to determine whether there is sciatic nerve compression. The pear muscle tension test is the 4-character test, by doing this action, patients with pear muscle inflammation may have positive pathological signs, patients in doing the 4-character test accompanied by numbness and radiating pain in the lower limbs, mainly due to the pear muscle inflammation on the sciatic nerve compression resulting in numbness and radiating pain.