Which of the following bones are part of the appendicular skeleton?

• A. Femur
• B. Sacrum
• C. Vertebrae
• D. Sternum

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the difference between the axial skeleton and the appendicular skeleton. The axial skeleton includes bones that form the central axis of the body, such as the skull, vertebrae, ribs, and sternum. The appendicular skeleton includes bones of the limbs and girdles (pectoral and pelvic) that attach the limbs to the axial skeleton.
2. Step 2: Identify the bones listed in the problem and classify them. The femur is a long bone in the thigh and part of the appendicular skeleton. The sacrum, vertebrae, and sternum are part of the axial skeleton.
3. Step 3: Recall that the appendicular skeleton consists of the upper and lower limbs, as well as the girdles (shoulder and pelvic) that connect them to the axial skeleton. The femur is part of the lower limb and thus belongs to the appendicular skeleton.
4. Step 4: Exclude the sacrum, vertebrae, and sternum from the appendicular skeleton classification, as they are part of the axial skeleton. The sacrum is a fused bone at the base of the spine, vertebrae form the spinal column, and the sternum is the breastbone in the chest.
5. Step 5: Conclude that the femur is the only bone listed that belongs to the appendicular skeleton, based on its location and function in the body.