When you finish this chapter you will be able to:
Identify the bones, articulations, stabilizing ligaments, and musculature of the shoulder complex.
Explain how shoulder injuries may be prevented.
Describe the process for assessing injuries to the shoulder.
Recognize specific injuries that occur around the shoulder joint and describe plans for management.
The anatomy of the shoulder complex allows for a great degree of mobility. To achieve this mobility, stability of the complex is sometimes compromised and instability of the shoulder frequently leads to injury, particularly in those sports that involve overhead activity.35 Sport activities such as throwing, swimming, or serving in tennis or volleyball place a great deal of stress on the supporting structures (Figure 18–1). Consequently, injuries related to overuse in the shoulder are common in the athlete.17
Overhead activities can produce a number of shoulder problems. ©William E. Prentice
Dynamic movement and stabilization of the shoulder complex require integrated function of the rotator cuff muscles, the joint capsule, and the muscles that stabilize and position the scapula.26
The bones that comprise the shoulder complex and shoulder joint are the clavicle, scapula, and humerus (Figure 18–2). These three bones form the four major articulations associated with the shoulder complex: the sternoclavicular joint, the acromioclavicular joint, the glenohumeral joint, and the scapulothoracic joint.
Skeletal anatomy of the shoulder complex (anterior view). (From Saladin, K. S., Anatomy and physiology, 5th ed. Dubuque, IA: McGraw-Hill Higher Education, 2010.)
Shoulder complex articulations:
Ligaments at each of the four articulations act collectively to provide stability to the shoulder complex (Figure 18–3).
Shoulder complex articulations, ligaments, and bursae. (From Saladin, K. S., Anatomy and physiology, 5th ed. Dubuque, IA: McGraw-Hill Higher Education, 2010.)
The clavicle articulates with the sternum to form the sternoclavicular joint, the only direct connection between the upper extremity and the trunk. The sternoclavicular joint is extremely weak because of its bony arrangement, but it is held securely by the sternoclavicular ligament that pulls the clavicle downward and toward the sternum, in effect anchoring it. The clavicle is permitted to move up and down, forward and backward, and in rotation.36
The acromioclavicular joint is a gliding articulation of the lateral end of the clavicle with the acromion process of the scapula. This junction is rather ...