Washington Esthetician State Board Practice Exam

Which bone joins all the bones of the cranium together?

1. Frontal

2. Maxilla

3. Sphenoid

4. Occipital

The correct answer is: Sphenoid

The sphenoid bone is considered the keystone of the cranial floor because it articulates with all other cranial bones, making it essential for the structural integrity of the skull. This bone has a complex shape resembling a butterfly or bat, with a central body and wing-like extensions. Its position at the base of the skull allows it to connect with the frontal, temporal, parietal, and occipital bones, as well as the zygomatic bone, maxilla, and palatine bone. This unique attribute not only facilitates the formation of the skull but also plays a crucial role in housing important structures like the pituitary gland within the sella turcica portion of the sphenoid. In contrast, the frontal, maxilla, and occipital bones do not have the same extensive articulations with every other cranial bone; they connect with specific bones but are not the central connector as the sphenoid is. For example, the frontal bone primarily connects with the parietal bones at the coronal suture and does not play a role in linking all cranial bones. Understanding the role of the sphenoid in cranial anatomy is essential for comprehending the design and function of the skull as a whole.