L5, or L5, refers to the fifth lumbar vertebra in the human spine. It is located in the lower back, between the L4 vertebra and the sacrum. This vertebra plays a crucial role in supporting the upper body and allowing for movement and flexibility in the lower back. In addition to its anatomical significance, L5 is often associated with various medical conditions, such as herniated discs and sciatica. These conditions can cause pain and discomfort in the lower back and legs, highlighting the importance of maintaining spinal health and proper posture.