With one exception, the skull bones are joined by sutures. Which bone is the exception?

• A. Frontal bone
• B. Occipital bone
• C. Parietal bone
• D. Mandible

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the structure of the skull. The human skull is composed of several bones that are primarily joined together by immovable joints called sutures. These sutures are fibrous connections that hold the bones tightly together.
2. Step 2: Identify the exception to the suture rule. The mandible (lower jawbone) is the only bone in the skull that is not connected by sutures. Instead, it is connected to the temporal bone via the temporomandibular joint (TMJ), which is a movable synovial joint.
3. Step 3: Compare the mandible to other skull bones. The frontal, occipital, and parietal bones are all connected by sutures, making them immovable. The mandible's movable joint allows for functions such as chewing and speaking.
4. Step 4: Recognize the functional significance of the mandible's exception. The mandible's mobility is essential for mastication (chewing) and articulation during speech, which requires movement that sutures cannot provide.
5. Step 5: Conclude that the mandible is the correct answer because it is the only skull bone connected by a movable joint rather than sutures.