Roughly in the center of our skull, there is a small sphenoid bone
pocket called "Sella Turcica" (Turkish Saddle, due to its similarity
in shape to same), providing a snug and safe resting place for the
pituitary gland (hypophysis cerebri).

Does anyone have a reasonable explanation as to why this "saddle,"
located in one of the best protected spaces of the entire body (deep
inside the head) should have evolved?

To my thinking, the reason why the saddle evolved would have been that
our ancestors must have received very hard blows to the head quite a
lot, with the chances of survival proportional to the degree of
protection provided for the "master gland". However, this theory does
not make much sense to me, unless there were some mysterious hazards
in the past (no longer present) that made our ancestors receive a lot
of head traumas.

Henry Norman

MicroTech wrote:

On Jul 9, 2:30 pm, MicroTech gmail.com> wrote:

I found the following site with a diagram.
pathology2.jhu.edu/hypophysitis/howhlookslike.cfm

The explanation that came with the diagram was as follows:
"The size and the functionality of the opening are important in
protecting the pituitary from transmitted pulsations of the choroid
plexus and in protecting the optic fibers against suprasellar
extension of an expanding pituitary mass."

On Jul 9, 2:30 pm, MicroTech gmail.com> wrote:

I doubt that hard blows to the head would have provided the
selection pressures to shape a subsurface bone to such a highly
specific shape. A more spread out bone growth pattern would have
resulted for two reasons. First, the impact, once it traveled away
from the point of impact, would have spread out. Second, blows from
different directions would have traveled in different directions.
The selection pressure that shaped the Turkish saddle would more
likely be caused to protect against internally-generated stresses,
perhaps caused by the flow of fluids within the body. For example, the ...