Kaplan Nursing Entrance Practice Exam

Which type of joint is best described as a shoulder joint?

1. Hinge joint

2. Ball and socket joint

3. Pivot joint

4. Fixed joint

The correct answer is: Ball and socket joint

The shoulder joint is best described as a ball and socket joint due to its structural characteristics and the range of motion it allows. In a ball and socket joint, one bone has a rounded end (the ball) that fits into a cup-like structure of another bone (the socket), which enables a high degree of movement in multiple directions. This design allows for flexion, extension, abduction, adduction, internal rotation, and external rotation of the arm, making it one of the most versatile joints in the human body. This type of joint is essential for various activities that require the arm to move in multiple planes, such as reaching overhead, throwing, and rotating. In contrast, a hinge joint allows movement primarily in one direction (like the elbow), a pivot joint permits rotation around a single axis (like the joint between the first and second cervical vertebrae), and a fixed joint does not permit movement at all (like the sutures in the skull). Understanding these distinctions emphasizes the unique capabilities of the shoulder joint as a ball and socket joint.