Long bones are defined as being longer than they are wide.

• A. Short bones
• B. Flat bones
• C. Irregular bones
• D. Longer than they are wide

Answer: (D)

The key idea is bone shape classification by proportions. Long bones are identified by being longer than they are wide, which gives them a tubular shaft (diaphysis) and ends (epiphyses). This shape supports movement as levers and bears weight, with a thick outer compact bone along the shaft and a hollow medullary cavity. That’s why the statement describing long bones as longer than they are wide is the correct description.

Short bones, in contrast, are roughly cube-shaped with length about equal to width (carpals and tarsals). Flat bones are thin and curved, with two layers of compact bone sandwiching cancellous bone (cranial bones, sternum, ribs, scapula) to protect organs and provide attachment surfaces. Irregular bones have complex shapes (like vertebrae) and don’t fit the other categories.