👉 Trunk fluid, also known as cerebrospinal fluid (CSF), is a clear, colorless liquid that circulates within the central canal of the spinal cord and the subarachnoid space surrounding the brain and spinal cord. It plays a crucial role in maintaining the health of these structures by providing buoyancy to protect them from mechanical injury, facilitating the removal of waste products, and aiding in the transport of nutrients and hormones. The production and absorption of trunk fluid are tightly regulated, ensuring a stable environment for neural function.