The mid-concave position is a special clinical position in which the patient’s chest and head are elevated to about 20 degrees, and the patient’s lower extremities are elevated about 20-30 degrees. After the patient’s head and feet are elevated, the patient’s abdomen and buttocks are in a relatively low position, and this position is called the mid-concave position. The mid-concave position is generally used for patients in shock. Elevating the head and chest increases the expansion of the thorax as the diaphragm descends, which helps patients in shock to breathe and reduces venous return to the lower extremities, thereby reducing blood pooling and other phenomena. Through this position, the blood return to the heart can be increased, and the timely supply of blood to other organs of the body can help relieve the patient from shock. It can also be applied in the case of anesthesia or catheterization of female patients, and is also known clinically as the shock position, which is a position that can be used to relieve symptoms before the patient is resuscitated with fluids. When the patient is in the concave position, it is important to maintain the patient’s posture and not to allow the patient to lie flat, which is not conducive to blood return to the patient.