Which of the following is NOT classified as a flat bone?

The humerus is classified as a long bone, not a flat bone. Long bones are typically characterized by their elongated shape and consist of a shaft and two ends. They are primarily involved in the movement and support of the skeletal system, allowing for leverage and the ability to bear weight.

In contrast, flat bones, such as the skull, ribs, and pelvis, have a thin, flattened structure and are primarily involved in protection of internal organs and providing a broad surface for muscle attachment. The skull protects the brain, the ribs protect the thoracic cavity and its organs, and the pelvic bones support the weight of the upper body and protect the pelvic organs. Recognizing these classifications helps in understanding the functional roles of different types of bones within the human body.