Fornix, Brain

**Definition:** Heavily myelinated fiber bundle of the TELENCEPHALON projecting from the hippocampal formation to the HYPOTHALAMUS. Some authorities consider the fornix part of the LIMBIC SYSTEM. The fimbria starts as a flattened band of axons arising from the subiculum and HIPPOCAMPUS, which then thickens to form the fornix.

**Tree numbers:** - A08.186.211.180.405.600 - A08.186.211.200.885.287.500.345.600

**Synonyms:** - Fornix (Brain)