Ventriculus Terminalis of the Conus Medullaris

Terminal ventricle

Syn : Ventriculus terminalis, or fifth ventricle is widest part of the central canal of the spinal cord that is located at or near the conus medullaris.
It was described by Stilling in 1859 and Krause in 1875.
Krause introduced the term fifth ventricle after observation of normal ependymal cells.
The central canal expands as a fusiform terminal ventricle, and approximately 8-10 mm in length in the conus medullaris.
Although the terminal ventricle may be visible in the fetus and children, but is usually absent in adults.

Typically asymptomatic.
In some cases, the terminal ventricle may cause clinical symptoms due to its expansion.

Associations:
• Spina bifida.
• Arnold-Chiari syndrome.
• Tumors of the conus medullaris.
• Tethered cord.
• Myelomeningocele.
• Syringomyelia.
• Hydromyelia. In hydromyelia, a dilation of the central canal of the spinal cord is caused by an increase of cerebrospinal fluid.
• Syringohydromyelia (i.e., both Syringomyelia and Hydromyelia)