According to the American Academy of Orthopaedic Surgeons, 90 percent of disc herniations occur between the fourth and fifth (L4/L5) lumbar (lower back) vertebrae. An L4/L5 bulging disc, or disc herniation, can cause significant symptoms in the back and the legs. The spinal column is a complex structure composed of vertebrae (bones) and discs (cartilage). The main functions of the vertebrae are to protect the spinal cord from injury and to provide support for the vital organs of the abdomen and thorax. The discs are located between each vertebrae and allow the spinal column to be flexible. Sometimes the discs can herniate, or move, into the spinal canal and compress the nerves coming off the spinal cord. According to the Mayo Clinic, the compression of nerves by discs can cause significant symptoms.
Radiating Pain
Sciatica is the symptom that convinces doctors that an L4/L5 disc herniation has occurred. The sciatic nerve originates from the lower spinal cord, runs through the buttocks and down the back of the leg. According to the Mayo Clinic, sciatica is a radiating pain that starts in the buttocks and shoots down the back of the leg. This pain can also cause numbness and tingling. The radiating pain is termed "sciatica" because the sciatic nerve is compressed by the disc herniation, which is responsible for this symptom. "Sciatica" is a term that describes a symptom, not a medical condition.
Leg Weakness
Weakness is a common symptom associated with a L4/L5 bulging disc, according to the Mayo Clinic. The herniated disc compresses the nerve that is responsible for sending signals to the muscles in the lower legs. Because this nerve is compromised, the signal becomes weak and results in muscle weakness. Weakness in the lower leg can impair the ability to walk or perform daily activities. You will likely notice more weakness in the muscles of the ankles and the toes than in the upper leg muscles.
Back Pain
The Mayo Clinic states that low back pain is a symptom of L4/L5 disc herniation. This occurs because the herniated disc also compresses nerves that are responsible for detecting sensation in the back. In addition, there may be other reasons for your low back pain that may or may not be related to a disc herniation.
