Two longitudinal eminences located on the ventral surface of the medulla oblongata formed by the corticospinal tract fibers.

The fiber bundles consisting of descending axons from the primary motor cortex. radial glial cell. A glial cell that extends from the ventricular zone to the marginal zone during early neural development. Migrating neurons leaving the ventricular zone follow the long thin radial glial cells.

Pyramids is the seventh Discworld novel by Terry Pratchett, published in 1989.