Conus medullaris

The conus medullaris is the terminal end of the spinal cord. It occurs near lumbar nerves 1 (L1) and 2 (L2). After the spinal cord terminates, the spinal nerves continue as dangling nerves called the cauda equina.The upper end of the conus medullaris is usually not well defined. Blood supply: three spinal arterial vessels—the anterior median longitudinal arterial trunk and two posterolateral trunks. Other less prominent sources of blood supply include radicular arterial branches from the aorta, lateral sacral arteries, and the fifth lumbar, iliolumbar, and middle sacral arteries. The latter contribute more to the vascular supply of the cauda equina.