Lumbar Illustration of L4 and L5 with Interspinal Muscles

The medical illustrations in this gallery were commissioned to bring attention to a new finding; to demonstrate compression of the lumbar vertebrae L4 and L5 and the correlation of the contraction by the interspinal muscles.

Interesting Anatomical Facts

The lumbar vertebrae are the largest moveable part of the vertebral column. They are designated L1 to L5. Their anatomy consists of each vertebra separated by the vertebral disc. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together.

Protected by the vertebrae, the spinal cord spilts out between the vertebrae L1 and L2. The nervous tissue that extends below this point are individual strands that collectively form the cauda equina. In between each lumbar vertebra a nerve root exits, coming together again to form the largest single nerve in the human body, the sciatic nerve. Any disorders of the back may be of a result of this sciatic nerve having become trapped through spinal disc herntaion that can affect the nerve root. Pain manifests itself as lower back pain, that radiates along the sciatic nerve through the back of the leg and down to the foot. For illustrations on the sciatic nerve please see this gallery here.

Further anatomy detail includes the muscle. There are paired muscles located between the spinous processes of adjacent vertebrae; subdivided into cervical, thoracic, and lumbar muscles. The interspinale muscles are short bands of muscle fibers including the interspinales cervicis, interspinales thoracis, and interspinales lumborum muscles.