National Dental Assisting Examining Board (NDAEB) Practice Exam

Which dental arch is capable of movement through the action of the TMJ?

1. Maxilla

2. Mandible

3. Vomer

4. Palatine

The correct answer is: Mandible

The mandible is the only dental arch that is capable of movement through the action of the temporomandibular joint (TMJ). The TMJ connects the mandible to the skull, allowing for a wide range of movements essential for functions such as chewing, speaking, and making facial expressions. This joint is a unique hinge and sliding joint that permits the mandible to open and close, as well as move forward, backward, and side to side. In contrast, the maxilla, which forms the upper jaw, is a stationary bone and does not have independent movement; it is primarily fixed in place and does not articulate with the TMJ. The vomer and palatine bones are also stationary structures that form parts of the nasal and oral cavities, respectively, and do not participate in the movement of the jaw. Thus, the mandible distinctly stands out as the dental arch responsible for movement due to its articulating relationship with the TMJ.