Human Skull - ethmoid bone (calvarial bone #8)

The probe is pointing to the general area that the ethmoid bone is found in if we were to remove the superficial layer of bone to reveal the nasal cavity inside of the skull that contains the ethmoid bone. The ethmoid is the bone that separates the nasal cavity from the brain. The ethmoid is located anterior to (in front of) the sphenoid bone, and consists of 2 masses--one on each side of the nasal cavity--which are joined horizontally by 2 "cribiform plates".

Here is a picture of the ethmoid bone by itself (posterior view) from "A Brief Atlas of the Human Body" (2e).