What is the primary characteristic of cancellous bone?

The primary characteristic of cancellous bone is that it is lightweight and porous. Cancellous bone, also known as trabecular or spongy bone, is found mainly in the interior of bones and has a honeycomb-like structure, which contributes to its porosity. This unique structure allows cancellous bone to be less dense than cortical (or compact) bone, playing a vital role in reducing the overall weight of the skeletal system while still providing strength and support. The porous nature of cancellous bone is essential for its function, as it facilitates the storage of bone marrow and the production of blood cells, as well as the absorption and distribution of forces throughout the skeletal framework.

In contrast, the other options do not accurately describe cancellous bone. Dense and hard characteristics are more representative of cortical bone. Cancellous bone is not restricted to the skull; it is also found in various other locations in the body, such as the ends of long bones and within the vertebrae. Moreover, it is not made entirely of solid bone tissue; instead, its structure includes trabecular spaces that enhance its lightweight quality. Understanding these characteristics is crucial for practicing effective coding in medical contexts related to bone health and surgical procedures.