The location of the lumbar vertebrae L4 and L5 are located at the most inferior part of the lumbar spine, as there are a total of five lumbar vertebrae, and therefore L4 and L5 are located at the most inferior part of the lumbar spine where they intersect with the sacral vertebrae. Patients can simply locate them in the following way: 1. Patients can locate L4 and L5 through the sacral spine by first asking their family members to help find the posterior superior iliac spine at the posterior lateral side of the hip near the lumbar region, which is commonly known as the lumbar eye. When the patient bends over, there is a very symmetrical bony protrusion on both left and right sides, and there is a depression here when the patient is upright, and this part is the posterior superior iliac spine, the intersection of the line of the bilateral posterior superior iliac spine and the posterior median line, which is basically located at the most upper part of the sacral spine. The patient can find this area by counting the thoracic vertebrae, and the patient needs to find the most inferior rib on both sides of the back of the waist, which is the 12th rib. The 12th rib can be felt in the direction of the spine to the 12th thoracic vertebra. The 12th thoracic vertebra is felt downward in the posterior midline in turn, and the spinous processes of L1-L5 can be gradually felt.