Question

Which letter indicates a bony projection from the ethmoid bone?

A) A
B) B
C) C
D) D
E) E

Answer 1

Letter B indicates a bony projection from the ethmoid bone. Thus the correct option is B.

Explanation

The bony projection from the ethmoid bone is called the "crista galli," which translates to "rooster's comb." This structure is crucial as it serves as an attachment point for the falx cerebri, a fold of dura mater that separates the brain's hemispheres.

Positioned superiorly within the cribriform plate of the ethmoid bone, the crista galli's distinct shape aids in stabilizing the brain within the skull and safeguarding it from excessive movement. Its strategic location also allows for the passage of olfactory nerves through the small openings in the cribriform plate, enabling the sense of smell.

This bony prominence stands out in its significance for both structural and neurological functions within the skull, making it an identifiable landmark in anatomical studies.

Thus the correct option is B.

Answer 2

The letter indicating a bony projection from the ethmoid bone is C, representing the crista galli (option C).

Step-by-step explanation:

The letter that indicates a bony projection from the ethmoid bone is C. This bony projection is known as the crista galli, which is an upward projection from the ethmoid bone. The ethmoid bone is a single, midline bone that forms important structures within the skull, including the upper portion of the nasal septum, the roof and lateral walls of the upper nasal cavity, and contributes to the medial wall of the orbit. Another downward projection of the ethmoid bone is the perpendicular plate which forms the upper nasal septum.

Hence, the answer is option C.