Chapter 32, Problem 23A

Summary Introduction

Introduction:

Human Skeleton is divided in two parts:

1. The axial Skeleton
2. The appendicular skeleton

The appendicular skeleton is a skeleton part in vertebrates where the bones are supporting the appendages. They include the elements within the limbs, supporting shoulder girdle, pectoral and pelvic girdle.

Answer to Problem 23A

Correct answer:

The correct answer is option (a) shoulder girdle.

Explanation of Solution

Explanation/justification for the correct answer:

Option (a) shoulder girdle is a part of the appendicular skeleton that connects the arm from all sides. Example: clavicle and scapula. These shoulder girdle also known as pectoral girdles provide structural support to the shoulder. They also help in motion by connecting muscles that are important for the arm and shoulder movement.

Explanation for incorrect answer:

Option (b) skull consists of the cranium that protects the brain and the facial bones that form the lower part of the skull. Cranium comprises of eight bones that are connected with sutures. They are not a part of the appendicular skeleton.

Option (c) rib cage contains 12 pairs of ribs and a sternum. They protect the lungs and heart. One end of the rib cage is flattened whereas the other end is rounded and they are also not a part of the appendicular skeleton.

Option (d) vertebral column is the central part of the skeleton present in the vertebrates. They give support to the body posture and protect the spinal cord. They are not a part of the appendicular skeleton.

Conclusion

The part of the appendicular skeleton is the shoulder girdle as the bones lying along the central axis are the appendicular skeleton.