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William E. Prentice

OBJECTIVES

When you finish this chapter you should be able to

  • Point out the critical anatomical features of the four articulations in the shoulder complex.

  • Perform an in-depth evaluation of the shoulder complex.

  • Recognize the steps that can be taken to minimize the chances of injury to the shoulder complex.

  • Explain how shoulder stability is maintained by the joint capsule, ligaments, and muscles.

  • Summarize the anatomical and functional relationship between shoulder stability and shoulder impingement.

  • Identify the etiology and recognize the symptoms and signs of specific injuries that occur around the shoulder joint, and discuss plans for management.

  • Formulate a general plan that may be effectively incorporated into a rehabilitation program for treating a variety of injuries in the shoulder complex.

INTRODUCTION

The shoulder complex, as the name implies, is an extremely complicated region of the body. Because of its anatomical structure, the shoulder complex has a great degree of mobility. This mobility requires some compromise in stability, and thus the shoulder is highly susceptible to injury.83 Many overhead activities—in particular, those that involve repetitive overhead movements—place a great deal of stress on the supporting structures (Figure 22–1). Consequently, injuries related to overuse in the shoulder are commonplace. Some understanding of the anatomy and mechanics of this joint is essential for the athletic trainer.

FIGURE 22–1

Vigorous and/or repetitive overhead activities, such as (A) serving in tennis or (B) an everyday activity, such as painting, can result in a variety of shoulder injuries. (a) Mike Watson Images/Getty Images; (b) William E. Prentice

ANATOMY OF THE SHOULDER

Bones

The bones that make up the shoulder complex and shoulder joint are the clavicle, sternum, scapula, and humerus (Figure 22–2).

FIGURE 22–2

(A) Skeletal anatomy of the shoulder complex. (B) Anatomy of the scapula.

Clavicle The clavicle is a slender, S-shaped bone approximately 6 inches (15 cm) long. It supports the anterior portion of the shoulder, keeping it free from the thoracic cage. It extends from the sternum to the tip of the shoulder, where it joins the acromion process of the scapula. The shape of the medial two-thirds of the clavicle is primarily circular, and its lateral third assumes a flattened appearance. The medial two-thirds bends convexly forward, and the lateral third is concave. The point at which the clavicle changes shape and contour presents a structural weakness, and the largest number of fractures to the bone occur at this point. Lying superficially with no muscle or fat protection makes the clavicle subject to direct blows.

Sternum The sternum, also ...

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