American Academy of Professional Coders (AAPC) Practice Exam

Which is the largest sesamoid bone in the body?

1. Cuboid

2. Patella

3. Vertebra

4. Humerus

The correct answer is: Patella

The largest sesamoid bone in the body is the patella. Sesamoid bones are small, round bones that are typically embedded within tendons and help with the movement and function of joints. The patella, commonly known as the kneecap, plays a critical role in the knee joint by providing a smooth surface for the quadriceps tendon to glide over the femur, enhancing the leverage and strength of the quadriceps muscle during movement. This increases the efficiency of the knee joint during activities such as walking, running, and jumping. In contrast, the cuboid is a tarsal bone located in the foot and does not belong to the sesamoid category. Vertebrae make up the spinal column and are not categorized as sesamoid bones. The humerus is the long bone of the upper arm and also does not fit within the definition of a sesamoid bone. Therefore, the patella is distinctly recognized as the largest sesamoid bone due to its size and function in the human anatomy.