The throwing shoulder in overhead athletes presents a unique challenge to clinicians. An enormous amount of force is directed across the shoulder in the process of throwing, as the athlete must rapidly rotate their arm during a short time period.¹ Further, the athlete must achieve peak velocity, but also attain extreme precision with respect to the target.² Understandably, this action, especially when performed frequently, can result in injury to the shoulder.¹ In the quintessential throwing sport of baseball, the shoulder has been found to be the most frequently injured body part, comprising 31 percent of all injuries.^3,4 In addition to baseball, other throwing sports where shoulder injury may occur include softball, javelin, and football (especially quarterbacks). Common findings in the throwing athlete include impingement, rotator cuff tears, superior labrum anterior to posterior (SLAP) tears, instability, and a glenohumeral internal rotation deficit (GIRD).²

There are several aspects of a patient’s background that are relevant when examining the throwing shoulder.^5,6 While the majority of patients will present with pain during throwing, other subtle symptoms may be present, such as a decrease in throwing velocity, changes in throwing accuracy, or feeling that the arm “went dead.”¹ Further, a thorough history should be obtained with respect to the history of repetitive throwing. Non-adherence to pitch counts and year-round training, or early specialization, contribute to injuries in youth athletes in particular. It is especially important to note overuse of the throwing arm from inadequate rest, which can manifest in pitchers who play in back-to-back games.

History and Phases of Throwing

A thorough understanding of the phases of throwing is crucial in the evaluation of shoulder injuries in the throwing athlete.^1,4,5 Notably, there are six phases of the throwing motion, each of which poses a unique strain on the shoulder. It begins with the windup, progresses to stride, early and late arm cocking, then acceleration, followed by deceleration, and ultimately concludes with the follow-through (figure 11.1).^5,7

Combined, all of these phases occur in less than two seconds.² The risk of injury to the shoulder is greatest in the transition between the late cocking and early acceleration phases of throwing.^4,8 In this position, the shoulder rapidly transitions from maximal external rotation to internal rotation, which results in the greatest forces and angular velocities on the shoulder.⁸

Careful attention should be directed to the phase of the throwing motion that is causing the patient pain or discomfort. For example, throwing athletes with anterior instability of the shoulder will report symptoms during the late cocking or early acceleration phase of throwing.¹ Conversely, throwing athletes with posterior instability of the shoulder will report symptoms during the follow-through phase of throwing.¹ Furthermore, the specific location of the pain or discomfort in the shoulder should be noted as well. Anterior pain is most often associated with subscapularis, biceps tendon, or joint capsule and anterior labral injury.¹ Anterolateral pain is associated with supraspinatus injury, and posterior pain is associated with infraspinatus or joint capsule and posterior labral injury.¹

Physical Examination

Physical examination of the throwing shoulder should begin with observation of the affected and unaffected shoulder.⁶ Examiners can often observe asymmetry of the shoulder musculature secondary to developmental changes occurring as a result of youth participation. All borders of the scapula should be inspected for potential signs of winging. Examiners should also look for signs of muscle atrophy, especially with respect to the supraspinatus and infraspinatus. Then, the examiner should palpate for any areas of tenderness or crepitation. It is specifically important to palpate at the acromioclavicular joint, biceps tendon, and posterior joint line of the shoulder, as these areas may be associated with throwing-related shoulder pathology.⁶

Further, passive and active range of motion and strength should be assessed. Notably, the throwing shoulder typically exhibits greater external rotation and less internal rotation compared to the contralateral, nonthrowing shoulder (video 11.1; figure 11.2).⁶ Further, it is also important to assess for internal rotation of the glenohumeral joint while a patient is lying supine to stabilize the scapula (figure 11.3).⁹

These changes in range of motion in throwing athletes occur due to stretching of the anterior capsule, tightness of the posterior capsule, and increased humeral and glenoid retroversion due to repetitive throwing while the growth plates were open.¹⁰ It has been shown that these adaptive changes occur in adolescence.¹⁰ The increased external rotation is one of the things that allows the throwing athlete to generate more acceleration across the ball and throw at a higher velocity. Unfortunately, the cost of the added external rotation is less internal rotation. Specifically, this concept is known as glenohumeral internal rotation deficit (GIRD). GIRD is defined as a deficit of greater than 20 degrees in internal rotation in the throwing shoulder compared to the non-throwing shoulder. This can be exacerbated by posterior capsular tightness and can be especially problematic when there is a loss of more than 25 degrees of internal rotation in the affected shoulder compared to the contralateral shoulder.¹¹

Special Tests

In addition to GIRD, superior labrum anterior to posterior (SLAP) tears are also common in throwing athletes.¹² There are various special tests to evaluate the integrity of the superior labrum, including O’Brien’s active compression test and the anterior slide test (video 11.2).¹³

In the O’Brien’s test, the affected arm is held in 90 degrees of forward elevation and positioned in 10 to 15 degrees of adduction.¹³ In the first position, the forearm is pronated with the thumb pointing downward, and the examiner places a downward force on the arm with the patient providing resistance upward. The patient is asked if any pain occurs with this maneuver. In the second position, the forearm is supinated until the thumb is pointing upward. The examiner repeats the downward force with the patient providing upward resistance. The patient is again asked if any pain occurs with this maneuver. A positive test occurs when there is pain in the first position that is alleviated in the second position, and a positive result is suggestive of a SLAP lesion.¹³ The anterior slide test can also assess for SLAP lesions (video 11.3).¹⁴

As described in chapter 4, the patient is seated with the hand of the affected side placed on the hip with the fingers anterior and thumb posterior to the waist. The examiner stands behind the patient and, with one hand on the elbow and the other on the shoulder girdle, applies an anterosuperior force to the arm while simultaneously stabilizing the scapula from behind. This maneuver brings the humerus in contact with the superior labrum. The test is considered positive if pain is reproduced with the maneuver.¹⁴

Frequent overhead throwing can also predispose individuals to tearing and gradual laxity of the joint capsule and adjacent stabilizing structures.^1,6 A test to evaluate the shoulder for instability due to anterior or posterior labral tears is the anterior and posterior load and shift test (video 11.4).^15,16 The test can be performed with the patient supine. The examiner applies an axial load to the humerus into the glenoid fossa while also applying an anteriorly directed force followed by a posterior force. The test is considered positive when there is increased translation present. Translation is graded on a scale from 0 to 3 as outlined in chapter 3. Further, the apprehension, relocation, and anterior release tests can be performed to assess for anterior instability of the shoulder (video 11.5).¹⁶ The examiner places the supine patient’s shoulder in abduction with the elbow in 90 degrees of flexion. First, the examiner performs the apprehension test by externally rotating the shoulder in the abducted position, assessing for discomfort or a sense of instability in the patient. Next, the examiner places their hand on the anterior shoulder in the relocation test, assessing if the discomfort disappears with a gentle posteriorly directed force. Lastly, the examiner removes their hand from the anterior shoulder in the anterior release test, assessing if the discomfort reappears.^15,16

In throwing athletes, the rotator cuff can also be a source of pain or dysfunction, as throwing athletes may present with impingement and/or rotator cuff tears.^1,6 Uniquely, extreme abduction and external rotation can lead to contact between the humeral head and the undersurface of the rotator cuff, which can result in articular-sided cuff tearing. As described in chapter 1, there are many ways to assess for impingement (video 11.6), including the Neer impingement sign and the Hawkins test. Rotator cuff integrity can be assessed using several tests, including the Jobe test, external rotation strength test, external rotation lag sign, lift off test, internal rotation lag sign, belly press test, and Hornblower’s sign.

Finally, in throwing athletes, the latissimus dorsi and teres major are two muscles that can be injured.¹⁷ These muscles serve as internal rotators of the humerus and are active during the cocking and acceleration phases of the throwing motion. A thrower with this injury typically presents with pain in the upper arm and affected axilla. Furthermore, one would expect tenderness along the teres major and latissimus dorsi upon palpation. The teres major muscle originates from the posterior surface of the inferior angle of the scapula and inserts on the medial humerus.¹⁸ The latissimus dorsi is a broad muscle of the back and originates from the spinous process of thoracic vertebrae T7–T12, thoracolumbar fascia, iliac crest, inferior 3–4 ribs, and inferior angle of the scapula, and it inserts medial to the bicipital groove of the humerus, just lateral to the insertion of the teres major.¹⁹

Throwing athletes can be affected by a wide variety of shoulder pathology, including impingement, rotator cuff tears, instability, SLAP tears, and glenohumeral internal rotation deficits.² It becomes imperative to gather a detailed and in-depth history, as findings may be subtle and include seemingly vague complaints such as a decrease in throwing velocity or accuracy.¹ In addition, evaluation of the throwing athlete is complex and combines the physical examination for all these conditions and the full kinetic chain. Final diagnosis depends on a comprehensive history and physical examination, in combination with advanced imaging studies.¹

Key Terminology

Anterior Slide Test

Physical examination maneuver performed in the assessment of a SLAP tear. The patient is standing upright or sitting on the examination table with their hands on their hips. The examiner stabilizes the scapula with one hand and places the other hand under the patient’s elbow, then applies an axial compressive force to the patient’s elbow simultaneously with an anterior-directed force to the humerus. A test is positive if the patient experiences pain in the anterior shoulder with this maneuver. ↵

Apprehension, Relocation, and Anterior Release Tests

Physical examination maneuvers for anterior shoulder instability. The patient is supine with the shoulder in 90 degrees of abduction, the shoulder in full external rotation, and the elbow in 90 degrees of flexion. The apprehension test is positive if the patient feels discomfort, or a sense of instability in this position. The relocation test is performed with the patient in the same position. The examiner applies a posterior force to the affected shoulder with their hand, and the test is positive if the patient no longer feels a sense of instability. The anterior release test is performed with the examiner’s hand now removed from the shoulder. A positive test result occurs if the patient again has a sense of anterior apprehension. ↵

Glenohumeral Internal Rotation Deficit (GIRD)

Deficit of greater than 20 degrees in internal rotation in the throwing shoulder compared to the non-throwing shoulder, commonly seen in throwing athletes. ↵

Hawkins Test

A test for subacromial impingement where the examiner places the patient’s shoulder in 90 degrees of flexion and the patient’s elbow in 90 degrees of flexion, and maximally internally rotates the shoulder by applying a downward force to the wrist. A positive test result is noted when pain is elicited with the maneuver. ↵

Jobe Test

A test for the assessment of rotator cuff (supraspinatus) pathology. The patient’s arms are placed in 90 degrees of abduction, angled forward 30 degrees, and internally rotated so that the thumbs face the floor. The examiner applies a downward force to the patient’s arm, asking the patient to resist the force and keep their arm level. A positive test is noted if pain and/or weakness is elicited by the maneuver. ↵

Load and Shift Test

Physical examination maneuver used to assess anterior and posterior instability. The examiner applies an axial load to the humerus into the glenoid fossa while also applying either an anterior or posterior force. A test is graded on a scale of 0 to 3 depending on the degree of anterior translation (anterior instability) or posterior translation (posterior instability) of the humerus relative to the glenoid. ↵

Neer Impingement Sign

A test for subacromial impingement where the examiner stabilizes the scapula of the affected shoulder with one hand and passively elevates the arm with the other hand. A positive test result is indicated by pain in the arc between 70 and 120 degrees of forward elevation. ↵

O’Brien’s Active Compression Test

Physical examination maneuver used in detecting SLAP tears and acromioclavicular joint pathology. The patient’s arm should be placed in 90 degrees of forward elevation with the elbow fully extended, and the arm adducted 10 to 15 degrees. In the first position, the patient’s thumb is directed to the floor and the examiner applies an inferiorly directed force to the patient’s arm, while the patient resists. In the second position, the patient’s thumb is now directed toward the ceiling, and the examiner again applies an inferiorly directed force to the patient’s arm while the patient resists. A positive test occurs if there is pain in the glenohumeral joint in the first position with the thumb directed downward that is alleviated in the second position. A “deep” location of pain is suggestive of a SLAP tear, while a “superficial” location of pain is suggestive of acromioclavicular joint (ACJ) pathology. ↵

Superior Labrum Anterior to Posterior (SLAP) Tears

Injury to the superior aspect of the labrum, which is also the attachment site of the long head of the biceps tendon. ↵

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