Which type of bone primarily supports weight and withstands compressive forces?

• A. Cortical bone
• B. Trabecular bone
• C. Spongy bone
• D. Compact bone

Answer: (A)

Cortical bone, also known as compact bone, is the type of bone primarily responsible for supporting weight and withstanding compressive forces. This dense and solid structure forms the outer layer of bones and provides strength and rigidity. Its highly organized arrangement of osteons (the structural units) allows it to endure heavy loads and resist deformation.

Cortical bone is crucial in the limbs and vertebrae, where the mechanical demands are high. Its thickness can vary depending on the part of the skeleton, corresponding to functional requirements. For example, areas that experience more stress will have a greater thickness of cortical bone to provide needed support.

Other types of bone like trabecular (or spongy) bone have a more porous structure and are primarily involved in metabolic functions such as the production of blood cells and mineral storage. While they do have some capacity to support loads, their primary role is not as a weight bearer but rather in providing structural support and housing marrow.