The conus medullaris is the terminal end of the spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2). After the spinal cord tapers out, the spinal nerves continue as dangling nerve roots called cauda equina

Cauda equina

The cauda equina is a structure within the lower end of the spinal column of most vertebrates, that consists of nerve roots and rootlets from above...

. This terminal nerve root tail is referred to as the filum terminale

Filum terminale

The filum terminale , is a delicate strand of fibrous tissue, about 20 cm. in length, proceeding downward from the apex of the conus medullaris. It gives longitudinal support to the spinal cord and consists of two parts:...

. The upper end of the conus medullaris is usually not well defined.

Blood supply

The blood supply consists of 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.

Pathology

Conus medullaris syndrome is a collection of signs and symptoms associated with injury to the conus medullaris.