The terminal ventricle (ventriculus terminalis, fifth ventricle or ampulla caudalis) is the 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 (or conus terminalis). Although the terminal ventricle is visible in the fetus and children, it is usually absent in adults.
Detection and Diagnosis
Sometimes, the terminal ventricle is observed by MRI or Sonography in children less than 5 years old. An MRI scan can be particularly helpful in its detection.
In pathological conditions, an MRI is useful at the level of the conus medullaris. Findings may be related to the following:
In some cases, the terminal ventricle may cause clinical symptoms due to its expansion.