Question

which cranial bone spans the width of the cranial floor?
○ occipital
○ sphenoid
○ ethmoid
○ temporal
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Explanation:

To determine the cranial bone that spans the width of the cranial floor, we analyze each option:

• Occipital: Mainly forms the back of the skull, not the width - spanning part of the cranial floor.
• Sphenoid: The sphenoid bone is a butterfly - shaped bone that spans the width of the cranial floor, contributing to the middle cranial fossa and other regions.
• Ethmoid: Primarily involved in the nasal cavity and anterior cranial fossa, not spanning the width of the cranial floor.
• Temporal: Forms the sides of the skull, not the width - spanning part of the cranial floor.

Answer:

B. Sphenoid