CHAPTER 43 ■ Injury: Shoulder MEGAN HANNON INTRODUCTION This chapter focuses on the diagnosis of the child with an acutely injured shoulder Injuries are described anatomically, from the sternoclavicular joint to the proximal humerus Figure 43.1 highlights important bony anatomy For the preverbal child with a possible shoulder injury presenting with an immobile arm, see Chapter 38 Immobile Arm DIFFERENTIAL DIAGNOSIS The differential diagnosis depends primarily on the location of the pain and the mechanism of injury ( Table 43.1 ) As with all pediatric musculoskeletal injuries, the differential diagnosis of shoulder injuries differs from adults because of the child’s open physes (growth plates) In children, trauma to the medial clavicle causes physeal (growth plate) fracture/separations because the epiphysis of the medial clavicle does not begin to ossify until 13 to 19 years of age and does not fully fuse until 22 and 25 years of age Once fused, trauma in this location generally results in sternoclavicular joint dislocations Most clavicular dislocations are anterior, and the patient has swelling and tenderness over the sternoclavicular joint If the dislocation is posterior, major vessels or the trachea may be injured Although subclavian vessels and the brachial plexus are just beneath the clavicle, they are rarely injured because the subclavius muscle is interposed between the bone and vessels, and the thick periosteum of the clavicle rarely allows it to splinter However, if injury to the brachial plexus or trachea does occur, the child may have dysphagia, hoarseness (laryngeal nerve), or difficulty breathing Anteroposterior and superiorly projected lordotic radiographs comparing both clavicles may not visualize the dislocation and CT is usually necessary Contrast is recommended to assess the great vessels as well as the bony anatomy The clavicle is a commonly fractured bone in children The clavicle is subject to any medially directed force on the upper limb (e.g., a fall on shoulder) but is commonly fractured by a direct blow A neonate’s birthing injury or an infant’s greenstick fracture of the clavicle may go unnoticed until the focal swelling of the developing callus is noted In the older child, the arm droops down and forward The child’s head may be tilted toward the affected side because of sternocleidomastoid muscle spasm Localized swelling, tenderness, and crepitations may be noted A dedicated clavicle radiograph will confirm the diagnosis Osteolysis is an uncommon cause of distal clavicle pain resulting from either minor trauma or repetitive stress (i.e., weight lifting, overhead athlete) In general, these patients present with to weeks of chronic pain or edema at the distal clavicle Radiographs are diagnostic Acromioclavicular (AC) joint injuries usually cause physeal fractures of the distal clavicle in patients younger than 14 years Older children may sprain or separate the AC joint Either injury is most often caused by a direct blow to the shoulder The child will have pain with any motion of the shoulder and tenderness over the AC joint Grade I and II injuries are nondisplaced Grade III and IV injuries are displaced 25% to 100%, and Grade V injuries are more than 100% displaced Bilateral radiographs may be obtained to compare the AC joint on the normal and affected sides Cosmetic deformities and degenerative changes of the distal clavicle may complicate these injuries, even with appropriate therapy Scapula fractures are rare in pediatrics and usually occur only after major direct trauma, such as a motor vehicle accident, a fall from a height, or a direct blow in sports such as American football The child will have tenderness over the scapula The patient often sustains other more life-threatening injuries (e.g., head injuries, rib fractures, or pneumothoraces) Dedicated scapular films improve yield over routine chest or shoulder radiographs The glenohumeral joint is shallow, allowing a wide range of motion but increasing the risk of dislocation Shoulder or glenohumeral joint dislocations are rare in children younger than 12 years of age but become common in adolescence as the skeleton matures The patient is injured when an already abducted and externally rotated arm is forcibly extended posteriorly (e.g., blocking in football or missing a dunk and striking the rim during basketball) This action leverages the humeral head out of the glenoid fossa More than 95% of all dislocations are anterior, and less than 5% are posterior The patient will be in severe pain, supporting the affected arm which is internally rotated and slightly abducted (i.e., the patient cannot bring the elbow to his or her side) The shoulder contour is sharp due to the prominent acromion, unlike the round contour of the opposite shoulder (see Fig 43.2 ) The trauma can damage the axillary nerve or fracture the glenoid fossa and/or the humeral head Sensation over the lateral deltoid muscle (axillary nerve distribution), lateral proximal forearm (musculocutaneous nerve distribution), and distal pulses should be evaluated and documented Radiographs should always be obtained because a humeral head or clavicular fracture may mimic a shoulder dislocation An AP, scapular “Y” view, and an axillary view are preferred to show the position of the dislocation and the presence of any fractures If the patient has a history consistent with dislocation but has more range of motion than expected and the radiograph is normal, the patient may have spontaneously reduced a dislocated shoulder or subluxated the glenohumeral joint and only sprained the ligaments overlying the glenoid fossa An apprehension test may confirm the subluxation diagnosis (see Fig 43.3 ) Actual tears of the rotator cuff are uncommon before 21 years of age However, if the rotator cuff muscles are damaged or weak, the humeral head is displaced upward during overhead motion This may impinge the tendon of the supraspinatus muscle and the subacromial bursa between the humeral head and the acromion or coracoid process Impingement symptoms usually occur with repetitive overhead motions (e.g., throwing a ball) The pain is commonly notable over the deltoid area though it may be poorly localized There are several tests for rotator cuff injuries that rely on fatiguing the secondary muscles and isolate the rotator cuff muscles including Neer, Hawkins, and anterior impingement testing The painful arc test (see Fig 43.4 ) has the best sensitivity and specificity Plain radiographs are usually normal, and magnetic resonance imaging is necessary to diagnosis rotator cuff injuries but does not need to be done emergently FIGURE 43.1 Anatomy of the shoulder ... clavicle may complicate these injuries, even with appropriate therapy Scapula fractures are rare in pediatrics and usually occur only after major direct trauma, such as a motor vehicle accident, a