In the posterior maxilla, how do the marrow spaces compare to those in the anterior maxilla?

• A. Slightly smaller marrow spaces.
• B. Slightly larger marrow spaces.
• C. The same size.
• D. There are no marrow spaces.

Answer: (D)

Marrow spaces reflect the amount of cancellous bone in a region. In the posterior maxilla, the area around the maxillary sinus is largely pneumatized and dominated by cortical bone, leaving little room for distinct cancellous marrow cavities. Because of this, there are essentially no marrow spaces in that region when you compare it to the anterior maxilla, which contains more trabecular bone with visible marrow cavities.