American Academy of Professional Coders (AAPC) Practice Exam

Which classification of bone is characterized as being longer than they are wide and typically found in the limbs?

1. Short

2. Flat

3. Long

4. Irregular

The correct answer is: Long

The classification of bone referred to in the question is long bones, which are indeed characterized by being longer than they are wide. This specific design allows for greater leverage and movement, making long bones essential in the limbs for activities such as walking, running, and jumping. Long bones, such as the femur in the thigh or the humerus in the upper arm, have a shaft called a diaphysis that is longer than its ends, which are termed epiphyses. This structure not only supports weight but also plays a critical role in facilitating movement due to joint articulation at the epiphyses. In contrast, short bones are approximately equal in their dimensions, flat bones have a thin and flattened shape suited for protection (like the skull), and irregular bones have complex shapes that do not fit neatly into any category, such as the vertebrae. Understanding these distinctions is key in anatomy and physiology, especially concerning their functional roles in the skeletal system.