You searched for: “foramen magnum
foramen magnum (s) (noun)
The large hole at the bottom of the cranium or head:

"The foramen magnum is the large opening in the base of the skull through which the spinal cord passes."

"The foramen magnum is situated in the occipital bone which forms part of the base and the back of the skull and this hole allows the brain stem to enter the spinal canal, where it continues as the spinal cord."

This entry is located in the following unit: for-, fora- + (page 1)