Lumbar spine Coloured Xray of four lumbar vertebrae of the human spine seen in antero posterior view Five lumbar bones are found in the lower back with those here being L at top to L at bottom Part of L which articulates with the sacrum of the pelvis is seen below L The lumbar vertebrae are the largest of the un fused vertebrae in the backbone Each vertebra comprises a wide disclike body with transverse bony processes projecting out sideways These bony processes are muscle attachment points Between each vertebra is a cartilaginous disc A canal inside each vertebra accommodates the spinal cord The spine is made up of vertebrae