Precommissurala fornix, Postcommissurala fornix,

Wire bundle/conduction path, one on the right and one on the left side, each containing 5-7 million small myelinated nerve fibers and emanating mainly from i.e. having their cell bodies in the hippocampal complex, more precisely in its subiculum part.

The nerve fibers initially gather into a flat band-like elevation or fringe (arch band/arch fringe, fimbria fornicis) on the upper side of the hippocampus. The vault band runs backwards along the tapered hippocampus formation, and becomes, the further back it goes, thicker and wider through the uptake of filaments from the underlying hippocampus formation. The arch band reaches its full size where it reaches the underside of the back of the cerebral beam (splenium corporis callosi). Here the vault band merges into, and forms the beginning of, the vault itself; the so-called vault shanks (Crus fornicis).

The flat wide arches swing around the pile of vision (thalamus) and then run forward attached to the underside of the brain beam . The arches make their way towards the middle line where they make contact with each other. Here, the right and left fornix exchange threads with each other, which cross-connects the hippocampus formations of the two sides with each other, the cross connection of the vault (commissura fornicis). The arches pull close to each other forward under the brain beam. They increasingly lose their flattened shape and become rounder. They are now called the corpus fornicis, descending more and more from the cerebral beam and hanging under it attached to the septum pellucidum. The vault strings then bend sharply downwards. They now have almost circular cross-sections and are called columna fornicis. The two, now spaghetti-like, bundles of wire reach down to the ventricular interval, form the anterior edge of the hole just behind the anterior transverse connection (commissura anterior), and then disappear into the lateral wall of the 3rd cerebral ventricle.

Hay. and we. Columna fornicis divides into two portions: a thinner precommissural part and a thicker postcommissural part.
The former run in front of - rostral about - the anterior cross-connection and end in the septal region. The precommissural vault section mediates round-trip traffic between the hippocampus and the septal region.
The postcommissural vault part, which forms the main part of the columna fornicis, runs behind - caudally about - the anterior transverse connection, disappears into the hypothalamus through the wall of the third ventricle and finally ends in the wart body (corpus mammillare).

The lateral ventricle braid (choroid plexus ventriculus lateralis) attaches along and in the outer (lateral) edge of the vault (tenia fornicis).

In summary, it can thus be said that the general concept of the vault (fornix) includes 4 smaller parts:
1/ vault band (Fimbria fornicis)
2/ Arch shanks (Crus fornicis)
3/ Corpus fornicis
4/ Column/end part of the vault (columna fornicis)