In the context of human anatomy, what is an opposable thumb?

• A. A thumb that is used primarily for gripping objects
• B. A thumb that is longer than the other fingers
• C. A thumb that can touch the tips of the other fingers on the same hand
• D. A thumb that is located on the opposite side of the hand

Answer: (C)

Verified step by step guidance

1. Understand the concept of an opposable thumb: In human anatomy, an opposable thumb refers to the ability of the thumb to touch the tips of the other fingers on the same hand, allowing for a wide range of movements and grips.
2. Recognize the importance of opposability: This feature is crucial for tasks that require precision and dexterity, such as writing, grasping small objects, and manipulating tools.
3. Identify the anatomical structure: The opposable thumb is characterized by a saddle joint at the base, which allows for rotational movement and greater flexibility compared to other fingers.
4. Consider evolutionary significance: The development of an opposable thumb is a key evolutionary trait that has enabled humans to perform complex tasks and use tools effectively.
5. Differentiate from other thumb characteristics: While a thumb may be longer or located on the opposite side of the hand, these features do not define opposability. The ability to touch other fingers is the defining characteristic.