INBDE (Integrated National Board Dental Examination) Practice Exam

Which three bones compose the cranial base?

1. Ethmoid, sphenoid, and occipital

2. Frontal, parietal, and temporal

3. Nasal, lacrimal, and maxillary

4. Zygomatic, mandible, and palatine

The correct answer is: Ethmoid, sphenoid, and occipital

The correct answer is A. The ethmoid, sphenoid, and occipital bones compose the cranial base. The ethmoid bone forms the anterior part of the base of the skull, the sphenoid bone contributes to the middle part of the base, and the occipital bone forms the posterior part of the cranial base. These three bones work together to provide structural support for the brain and help protect the delicate structures within the cranial cavity. The other options are incorrect: - Frontal, parietal, and temporal bones are part of the cranial vault, not the cranial base. - Nasal, lacrimal, and maxillary bones are part of the facial skeleton, not the cranial base. - Zygomatic, mandible, and palatine bones are also part of the facial skeleton and do not contribute to the cranial base.