Question: Which of the following is an example of a first-class lever in the human body?
A Bicep curl
B Walking
C Bending your knee
D Atlanto-Occipital Joint
Answer: Atlanto-Occipital Joint
| Aspect | Description |
| Name | Atlanto-Occipital Joint |
| Location | Base of the skull (Occipital bone) and the first cervical vertebra (Atlas) |
| Role as a Lever | Example of a first-class lever in the human body |
| Type | Synovial joint |
| Classification | Diarthrotic joint (freely movable) |
| Function | Allows nodding and flexion of the head |
| Fulcrum | Located between the effort (neck muscles) and the load (head) |
| Movement | Primarily responsible for flexion and extension of the head |
| Supports | The weight of the head, which can be considerable |
| Anatomy | Comprised of the atlas (C1) and the occipital condyles of the occipital bone |
| Muscles Involved | Sternocleidomastoid muscles sub occipital muscles and various neck muscles |
| Importance | Essential for nodding, tilting, and turning the head |
| Protection | Helps protect the spinal cord and supports the skull’s weight |