Chapter 12, Problem 12.1.1AYLO

Summary Introduction

To determine:

About the pectoralis minor and serratus anterior.

Introduction:

Muscles of the pectoral girdle are of two types, anterior group muscle and posterior group muscle. The anterior group contains two muscles, pectoralis minor and serratus anterior. The pectoralis minor arises from the 3-5 ribs, while, the serratus anterior arises from most of the ribs. The posterior group contains three deep muscles, the rhomboid minor, the rhomboid major, and levator scapulae.

Explanation of Solution

Pectoralis minor along with serratus anterior moves scapula laterally and forward around the chest wall. Pectoralis minor is attached to ribs 2-5 and coracoid process of scapula. It also protracts shoulder while reaching for the door handle. It also helps in picking up the suitcase by rotating the scapula and depressing the apex of the shoulders.

Serratus anterior is attached to almost all the ribs and medial border of scapula. It protracts scapula and is of prime importance in throwing, forward-reaching, and pushing actions. It also rotates scapula to elevate the apex of the shoulder, such as during lifting a suitcase. Moreover, the serratus anterior abducts the arm by fixing the scapula.

Conclusion

Pectoralis minor is attached to only3-5 ribs, but the serratus anterior is attached to almost all the ribs. Pectoralis minor is used in protracts shoulder, while serratus anterior protracts the scapula.