There are the following differences between the symptoms of lumbar disc herniation and femoral head necrosis: 1. The disc herniation has soreness in the lower back and radiating pain in the legs because of the stimulation and compression of the nerve roots, which continues along the sciatic nerve in a radioactive manner to the legs, and is more obvious along the course of the nerve, which will appear in the middle of the buttocks, the back or outside of the thigh, and radiates to the calf, even to the outside of the calf and the foot. In the early stage of femoral head necrosis, groin pain will appear, mostly confined to the buttocks and the anterior and lateral thighs, rarely extending to the calves or feet, and the pain is concentrated around the groin, without obvious radiation, or producing progressive pain or numbness along the direction of nerve travel.2. A positive straight leg raise test for lumbar disc herniation during examination, and a positive four-letter sign for femoral head necrosis of the hip joint, are more obvious differences. This is all a relatively obvious difference.