Final answer:
A ball-and-socket joint is a multiaxial synovial joint found at the hip and shoulder, providing extensive ranges of motion including rotation.
Step-by-step explanation:
Ball-and-Socket Joint Definition
A ball-and-socket joint is a type of synovial joint where a rounded, ball-like end of one bone (the "ball") fits into a cuplike depression (the "socket") of an adjacent bone. This unique structure allows for the greatest range of motion, making these joints functionally classified as multiaxial joints, capable of movements in multiple planes. Such joints are found in critical areas of the human body, specifically at the hip and shoulder joints, where they enable a wide range of movements including rotation and swinging motions.
Hip Joint: Here, the head of the femur fits into the deep socket known as the acetabulum, providing stability that is essential for weight-bearing and locomotion.
Shoulder Joint: The humerus head fits into the relatively shallow socket of the glenoid cavity, allowing a wide range of motion such as lifting, rotating, and swinging of the arm.