Scapular Fractures: What Radiologists Need to Know.

M u s c u l o s k e l e t a l I m a g i n g • R ev i ew Ropp and Davis Scapular Fractures

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Musculoskeletal Imaging Review

Alan M. Ropp1 Derik L. Davis Ropp AM, Davis DL

Scapular Fractures: What Radiologists Need to Know OBJECTIVE. The purpose of this article are to review scapular anatomy and function, describe imaging features of traumatic scapular injury, and discuss the role of diagnostic imaging in clinical decision making after shoulder trauma. CONCLUSION. Knowledge of scapular anatomy, function, injury patterns, imaging appearance, and clinical management is important for the radiologist to the care of patients who present with acute shoulder trauma.

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Keywords: CT, fracture, radiography, scapula, shoulder, trauma DOI:10.2214/AJR.15.14446 Received January 18, 2015; accepted after revision February 22, 2015. 1 Both authors: Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, 22 S Greene St, Baltimore, MD 21201. Address correspondence to D. L. Davis ([email protected]).

This article is available for credit. AJR 2015; 205:491–501 0361–803X/15/2053–491 © American Roentgen Ray Society

capular fractures are uncommon, accounting for only 3–5% of shoulder girdle fractures and fewer than 1% of all fractures [1]. High-energy trauma is the most common cause, and scapular fractures are frequently associated with other acute injuries, including rib fracture (53%), lung injury (47%), head injury (39%), spinal fracture (29%), and clavicle fracture (25%) [2]. The initial diagnosis of scapular fracture is often delayed or ignored, because clinical care in the acute setting is focused on patient resuscitation after one or more lifethreatening injuries [3–5]. Imaging plays the key role in identifying and classifying scapular fractures and thus guides clinical decision making. This article will review the use of diagnostic imaging for evaluating traumatic scapular fracture and describe imaging findings associated with operative management indications. Anatomy The scapula is a flat triangular bone with several distinct regions (Fig. 1). The glenoid fossa forms the articular surface of the scapula and connects to the scapular body via the neck of the scapula. The scapula serves as an attachment site for 17 muscles, which facilitate movement and form a functional softtissue envelope for the shoulder girdle [6]. These muscles are subdivided into scapulothoracic and scapulohumeral groups (Appendix 1). The rotator cuff muscles are a subcomponent of the scapulohumeral group.

Normal Biomechanics Background The scapula functions at the shoulder girdle as a base of motion and stability in association with the superior shoulder suspensory complex and the scapulothoracic, glenohumeral, and acromioclavicular joints. These articulations provide a functional link between the thorax and the upper extremity [7]. The superior shoulder suspensory complex comprises a bone and ligamentous ring formed by the scapula, distal clavicle, acromioclavicular joint, and coracoclavicular ligament. Scapular contributions include the glenoid, coracoid, and acromion process [8]. The superior shoulder suspensory complex, in concert with the scapulothoracic muscles, acts to suspend the upper extremity from the thorax. The scapula, through its relationship with the superior shoulder suspensory complex, is hung from the clavicle by the acromioclavicular joint and coracoclavicular ligament [9]. Scapular motion and stability rely on the sensorimotor system to coordinate the static and dynamic stabilizers of the shoulder girdle [10]. Coordination of scapulothoracic and scapulohumeral musculature contractions, in concert with biofeedback from the glenohumeral-capsuloligamentous complex, allows normal motion and functional stability [10]. Scapulothoracic Joint The scapulothoracic joint provides dynamic stability at the shoulder girdle through biomechanical support of the scapula and rotator cuff musculature [11]. The scapulotho-

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Ropp and Davis racic joint is fairly incongruent, with no direct bony connection between the scapula and thorax [12]. The serratus anterior, trapezius, rhomboid major and minor, and levator scapulae muscles are the main muscular stabilizers. The serratus anterior is most important for maintaining normal medial scapular angle and chest wall alignment, and the trapezius is most helpful for facilitating scapular motion in concert with the glenohumeral joint [6, 12]. The coordinated summation of scapulothoracic muscular forces acting on the scapula ultimately results in a movement of protraction or retraction from the normal resting orientation of the scapula [6, 13] (Fig. 2A). Protraction is the movement of the scapula toward the anterior thorax, whereas retraction is the movement of the scapula toward the vertebral column [12]. Three distinct individual variables of scapulothoracic motion are internal-external rotation, upward-downward rotation, and anteroposterior tilting [14, 15] (Figs. 2B– 2D). Normal scapulothoracic motion is dependent on simultaneous motion at the acromioclavicular and sternoclavicular joints, especially upward rotation; and, normal posterior tilting is largely influenced by the biomechanical motion of the acromioclavicular joint [14]. The scapulothoracic joint contributes to the stability of the glenohumeral joint and increases the range of motion at the shoulder girdle beyond that provided by the glenohumeral joint alone [6, 16]. Glenohumeral Joint Because the glenohumeral joint lacks actual inherent stability, the sensorimotor system must continually balance counteracting forces among the various muscles, ligaments, and bones at the shoulder girdle during all phases of motion [6, 10]. To accomplish this feat, the glenohumeral joint relies on the synchronized cooperation of static and dynamic stabilizers. Injury to the static or dynamic stabilizers can result in a functionally unstable glenohumeral joint [10]. Static restraint depends on the osseous geometry of the scapula, in addition to the glenoid labrum, the glenohumeral capsuloligamentous complex, and the negative intraarticular pressure of the joint [6, 11, 17]. The morphology of the glenoid fossa is important for stability and normal biomechanics [6]. The articular surface of the glenoid fossa is pear shaped, and the inferior half is one fifth larger than the superior half [11, 18]. The normal anteroposterior composite

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TABLE 1: Ideberg Classification of Intraarticular Glenoid Fractures [33] Type

Description

1

Anterior glenoid rim fracture

2

Inferior glenoid fracture involving the inferior neck

3

Superior glenoid fracture involving the base of coracoid process

4

Horizontal fracture through the neck and body, inferior to the spine

5

Combination of types 2 and 4

depth of the glenoid fossa and labrum is 5 mm, compared with 9 mm for the superoinferior depth [19]. A decrease in glenoid bone stock has a negative effect on glenohumeral stability [6]. A loss of glenoid bone stock of more than 21% in superoinferior depth or more than 25% of the anterior glenoid places stability at risk [20–22]. Additionally, the glenoid fossa is retroverted by 7° relative to the scapular body in healthy individuals [23]. Excessive retroversion or anteversion of the glenoid is also associated with glenohumeral joint instability [11, 23, 24]. Dynamic stability of the glenohumeral joint during active arm movements is maintained by a complex set of counterbalancing muscular contractions that keep the humeral head centered at the glenoid fossa throughout all ranges of motion [11]. At the mid range of the motion, when the glenohumeral ligaments are lax, dynamic stabilizers are the primary mechanism to keep the humeral head centered at the glenoid fossa [25]. The primary dynamic stabilizers of the glenohumeral joint include the rotator cuff, long head of the biceps brachii, and deltoid muscles, with additional support provided by the latissimus dorsi, teres major, and pectoralis major muscles [10]. Acromioclavicular Joint Stability at the acromioclavicular joint is also maintained by static and dynamic stabilizers. The acromioclavicular joint capsule and the acromioclavicular, coracoclavicular, and coracoacromial ligaments provide static stability, whereas the deltoid and trapezius muscles function as dynamic stabilizers [26]. Scapular motion occurs at the acromioclavicular joint and is defined as the degree of motion of the scapula relative to the clavicle. Imaging Radiographs An appropriate set of radiographs in the setting of acute scapular trauma includes anteroposterior, Grashey, axillary, and lateral scapular (Y) views [1, 9]. This radiographic series allows diagnosis of scapular and ipsilateral

clavicle fractures, as well as acromioclavicular and glenohumeral joint injuries. Grashey and axillary views are particularly useful for detection of intraarticular scapular fractures by providing direct visualization of the glenoid fossa and glenohumeral joint space. Acquisition of additional axillary views increases diagnostic sensitivity for difficult to see acromion and coracoid process fractures. CT Conventional 2D and 3D CT examinations are commonly performed in the setting of acute trauma. CT allows detailed characterization of bone, joint, muscle, or ligament injury at the shoulder girdle and is particularly helpful with identification of radiographically occult injuries [9, 27]. Thus, CT is more reliable and accurate for the detection and staging of scapular injuries than radiographs are; this is especially true for coracoid process, glenoid, and scapular neck fractures [28–31]. Dedicated shoulder CT is often not necessary in the setting of trauma, because reformatted 2D and 3D CT images are commonly acquired from the chest CT scan obtained on admission. CT image reformatting also allows creation of optimal 3D scapular images that correspond to the ideal scapular Y, Grashey, and anteroposterior radiographic views [28, 32] (Fig. 3). In addition, 3D CT images add value by mitigating artifacts produced by patient body habitus, patient positioning, and imaging technique [28]. Intraarticular Scapular Fractures Intraarticular fractures constitute 10–30% of all scapular fractures [3, 33, 34]. Ideberg et al. [33] classified intraarticular fractures of the glenoid fossa (Table 1), and this method of classification has been modified over time to define further scapular fracture patterns [35]. The most common cause is blunt trauma during a high-energy vehicular accident. Automobile and motorcycle collisions are typical, but bicycle, all-terrain vehicle, snowmobile, and Jet Ski crashes are other varieties of vehicular accidents that also result in scapular fracture

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Scapular Fractures [32, 36–38] (Fig. 4). Falling from a height or a pedestrian’s being struck by a moving vehicle are other common mechanisms [36, 38]. Intraarticular fractures of the glenoid account for the vast majority of open reduction and internal fixation (ORIF) procedures performed for management of scapular fracture [39]. Anterior shoulder dislocation is an additional mechanism associated with intraarticular fracture of the anterior glenoid [40] (Fig. 5). These Ideberg type 1 fractures of the glenoid are the most typical scapular fracture pattern encountered after shoulder dislocation, with shoulder dislocations accounting for two thirds of type 1 fractures [33]. Most nondisplaced intraarticular glenoid fractures are managed nonoperatively. However, displaced fractures demand consideration for operative fixation, because the various myotendinous units attaching to the scapula pull in different directions and contribute to distraction and rotational malalignment [35]. Nevertheless, the criteria for surgical management remain controversial, and the decision whether to perform ORIF is dependent on the surgeon’s preference and patient comorbidity, age, hand dominance, overall health, activities of daily living, and level of physical activity [1]. The most common goals for ORIF of displaced intraarticular scapular fracture are to reduce joint incongruity and prevent longterm posttraumatic osteoarthritis, instability, chronic pain, and decreased range of motion [32, 36, 38]. Indications for surgery include at least 4 mm of displacement at the articular surface and at least 20% involvement of the glenoid, although operative intervention is still considered to address instability even when these criteria are not met [1, 35] (Appendix 2). Other relative indications include an anterior rim fracture of greater than 25% of the articular surface or a posterior rim fracture of greater than 33%, fractures extending to the medial border of the scapula with displacement, glenoid rim fractures with associated persistent glenohumeral instability, and open fractures [1, 35]. Extraarticular Scapular Fractures Extraarticular fractures of the coracoid process, acromion process, neck, body, and spine account for the majority of scapular fractures. Traditionally, management of nonarticular scapular fractures has been conservative in nature. ORIF of extraarticular scapular fracture has been rare owing to the belief that the shoulder girdle’s wide range of motion sufficiently allows maintenance of activities of daily

living despite scapular posttraumatic deformity [1]. Certain extraarticular fractures, whether occurring alone or in combination with other injuries, have more recently challenged this dogma (Appendix 2). ORIF of displaced fractures has been touted as an avenue to decrease long-term pain, weakness, and functional disability [4, 8, 9, 41–43]; nevertheless, relative indications for extraarticular scapular fractures remain controversial [1]. Coracoid Process Coracoid process fractures represent 2–13% of scapular fractures [37, 42, 44]. These fractures most often occur at the base with minimal displacement [37, 45, 46]. Several mechanisms account for coracoid process fractures including direct blunt trauma or indirect trauma from a shoulder dislocation [47–49] (Fig. 6). An isolated fracture of the coracoid process in association with an anterior dislocation is often overlooked on radiographs [48]. Additional traumatic causes include axial loading related to an ipsilateral clavicle fracture, avulsion by myotendinous attachment, or avulsion by coracoclavicular ligament attachment during acromioclavicular joint separation [50–54]. Fractures of the coracoid process have been classified into five types according to anatomic location [45] (Fig. 7). Ogawa et al. [55, 56] described an alternative functional method of classification based on the anatomic relationship of the fracture to the coracoclavicular ligament: Ogawa type I coracoid process fractures are posterior to the coracoclavicular ligament, whereas type II fractures are anterior to the coracoclavicular ligament [55, 56]. Ogawa type I fractures are more common and have a greater tendency to be unstable [55–57]. Conservative management is the most common treatment of isolated coracoid process fractures. Surgical management is considered for fractures with more than 1 cm of displacement or intraarticular extension [37, 45]. Additional indications for surgical management include patients with significant future biomechanical demands, such as athletes and manual laborers [37, 46]. ORIF may also be considered after failed conservative management if the displaced bone fragment produces chronic irritation of the adjacent soft tissues or if the coracoid fragment or fragments cause an obstruction to the reduction of a shoulder dislocation [46, 49]. Acromion Process Acromion process fractures represent 8–16% of scapular fractures [3, 44, 58]. Motor

vehicle accidents are the most common cause [37]. In addition to direct blunt trauma, other mechanisms of acromion process fracture include indirect trauma after shoulder dislocation and avulsion by the deltoid muscle [37, 46]. Fractures of the acromion process have been classified according to anatomic location relative to the acromioclavicular joint, acromial angle, or scapular spine [59]. Kuhn et al. [60], however, described an alternative functional method based on the presence or absence of subacromial impingement: Kuhn type I fractures are minimally displaced, type II fractures are significantly displaced without subacromial space narrowing, and type III fractures are significantly displaced with subacromial space narrowing. Patients with Kuhn type III acromion fractures are prone to develop decreased range of motion and rotator cuff injury [60]. Nondisplaced acromion process fractures are most commonly treated with conservative management with good outcomes [58]. However, potential complications of nonoperative management include painful fracture nonunion or increasing fragment displacement [37, 61] (Fig. 8A). Additional long-term complications include decreased range of motion, subacromial impingement of the rotator cuff, pain, and shoulder weakness [37, 58, 60–62] (Fig. 8B). Thus, surgical management is considered for fracture with more than 1 cm of displacement, open fracture in the acute setting, or painful nonunion after conservative management [1, 37, 58, 63]. However, the optimal treatment remains controversial, and no single algorithm for treatment is widely accepted for acromion process fractures [58]. Scapular Neck, Body, and Spine As a group, extraarticular fractures of the scapular neck, body, and spine constitute the largest group of scapular fractures [5]. The scapular neck is second only to the body as the most common fracture site, accounting for 26–29% and 35–45% of scapular fractures, respectively [3, 5, 42]; fractures of the spine are less common and account for 6–11% of scapular fractures [3, 5, 42]. The mechanism of injury is typically violent and most often the result of a high-energy motor vehicle accident, although falling and a pedestrian’s being struck by a moving vehicle are also common mechanisms [3]. Most extraarticular fractures are treated conservatively. Isolated scapular body fractures are typically treated conservatively with good outcomes, even fractures with significant displacement [5, 42]. Nondisplaced scapular neck and spine fractures also have



Ropp and Davis favorable long-term outcomes with nonoperative management [5, 8]. Even though conservative management is also the mainstay of treatment of most displaced scapular neck and spine fractures, surgeons may choose to perform ORIF in certain instances. The displaced scapular neck fracture has received the most attention, because malunion has been implicated for the loss of normal biomechanics at the shoulder, stemming from rotator cuff dysfunction, scapulothoracic muscular injury, muscular fibrosis, and altered muscular efficiency [1, 5, 43]. Biomechanical studies also have suggested that displaced scapular neck fractures negatively affect the stability of the glenohumeral joint by altering the length of rotator cuff muscles during certain phases of movement [43]. Pain and weakness also have been reported in patients with significant displacement and malalignment of scapular neck fractures [5, 41, 42]. Grading of scapular neck displacement and rotation malalignment can be determined from radiographs or CT (Fig. 3). The Grashey view is useful for the measurement of the glenopolar angle and lateral border offset [1]. The gleno polar angle is a measure of rotational malalignment of the glenoid in relation to the anteroposterior axis perpendicular to the plane of the scapula [4, 32]. Normal glenopolar angle is 30–45°, and a glenopolar angle of up to 20– 22°, in isolation or in combination with other shoulder girdle injuries, is used as a relative indication for surgery to avoid long-term pain, weakness, and reduced capacity for activities of daily living [1, 4, 38, 41]. The glenopolar angle is formed by the intersection of two lines: the first line is drawn through the superior and inferior poles of the glenoid fossa, and the second is drawn through the apex of the superior pole of the glenoid fossa to the inferior angle of the scapula. Lateral border offset is defined by the distance of mediolateral displacement between the lateral margins of the superior and inferior scapular neck fracture fragments. A lateral border offset of at least 1–2 cm is another relative indication for ORIF [1, 9, 28, 38]. Angulation and translation are additional metrics for scapular neck malalignment obtained on the radiographic Y view [1]. Angulation is a measure of rotational deformity obtained in the plane parallel to the mediolateral axis of the scapula, and an angular deformity of at least 40–45° is a relative indication for surgery [1, 9, 38, 42]. Angulation is determined by drawing a line parallel to the superior neck fragment cortex and a line parallel to the inferior neck frag-

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ment cortex. Translation is defined by the distance of anteroposterior displacement between the superior and inferior scapular neck fracture fragments. Translation is measured as the distance between the anterior cortex of the superior fragment and the anterior cortex of the inferior fragment. Translation of at least 1 cm is a relative indication for surgery [9]. Floating Shoulder Injuries The original description of a “floating shoulder” injury comprised simultaneous scapular neck and ipsilateral clavicle fractures [8] (Fig. 9); however, the meaning of this term has more recently been expanded to include two or more disruptions of the superior shoulder suspensory complex [9]. Floating shoulder injuries are rare and represent less than 0.2% of shoulder girdle fracture patterns [64]. An unstable shoulder girdle occurs with two or more displaced fractures involving the scapular neck and clavicle, acromion process, or coracoid process or disruption of the acromioclavicular joint and coracoclavicular ligament [7, 8] (Figs. 10 and 11). Double disruptions of the superior shoulder suspensory complex are not isolated; for example, a clavicle fracture or a complete acromioclavicular joint separation can worsen the displacement of a scapular fracture, or vice versa [8, 9]. Scapular dyskinesis occurs in the setting of clavicular and scapular disassociation after clavicle fracture or acromioclavicular joint separation [65, 66]. A single injury of the superior shoulder suspensory complex is usually treated conservatively. However, two or more disruptions may have a negative impact on long-term healing and function [27, 37]. CT is particularly helpful for identifying injuries that are radiographically occult [27]. Displacements smaller than 1 cm for double disruptions of the superior shoulder suspensory complex usually have good outcomes with conservative treatment [67, 68]. Poor outcomes are most likely to occur in the setting of significant displacement at one or more sites in the ring [5, 7, 8]. Fracture displacements of more than 1 cm are considered significant and lead to a floating shoulder through the functional disassociation of the axial and appendicular skeletons [1, 5, 8, 69]. Bony complications include delayed union, malunion, or nonunion, and long-term functional deficits present as pain, subacromial impingement, rotator cuff dysfunction, and posttraumatic osteoarthritis [8, 9, 42]. Functional imbalance among the dynamic muscular glenohumeral and scapulothoracic forces at the shoulder girdle ensues after multiple displaced

disruptions of the superior shoulder suspensory complex [57, 62, 70]. The criteria for superior shoulder suspensory complex double disruption ORIF remain controversial because no uniform standards exist, and nonoperative management of extraarticular scapular fractures has been the traditional norm. The minimum amount of displacement to indicate surgical management is still debated [9, 71]. The decision to perform ORIF in these circumstances is dependent on the surgeon’s preference and patient comorbidity, age, hand dominance, overall health, activities of daily living, and level of physical activity [1]. The goal of surgical intervention for floating shoulder injuries is to reduce unstable fracture patterns, support an early program of physical rehabilitation, and prevent long-term functional deficits [58, 69]. Conclusion Knowledge of scapular anatomy, function, injury patterns, imaging appearance, and clinical management is important for the radiologist to guide the care of patients who present with acute shoulder trauma. References 1. Cole PA, Freeman G, Dubin JR. Scapula fractures. Curr Rev Musculoskelet Med 2013; 6:79–87 2. Baldwin KD, Ohman-Strickland P, Mehta S, Hume E. Scapula fractures: a marker for concomitant injury? A retrospective review of data in the National Trauma Database. J Trauma 2008; 65:430–435 3. McGahan JP, Rab GT, Dublin A. Fractures of the scapula. J Trauma 1980; 20:880–883 4. Romero J, Schai P, Imhoff AB. Scapular neck fracture: the influence of permanent malalignment of the glenoid neck on clinical outcome. Arch Orthop Trauma Surg 2001; 121:313–316 5. Nordqvist A, Petersson C. Fracture of the body, neck, or spine of the scapula: a long-term followup study. Clin Orthop Relat Res 1992; 139–144 6. Lugo R, Kung P, Ma CB. Shoulder biomechanics. Eur J Radiol 2008; 68:16–24 7. Rikli D, Regazzoni P, Renner N. The unstable shoulder girdle: early functional treatment utilizing open reduction and internal fixation. J Orthop Trauma 1995; 9:93–97 8. Goss TP. Double disruptions of the superior shoulder suspensory complex. J Orthop Trauma 1993; 7:99–106 9. Owens BD, Goss TP. The floating shoulder. J Bone Joint Surg Br 2006; 88:1419–1424 10. Myers JB, Lephart SM. The role of the sensorimotor system in the athletic shoulder. J Athl Train 2000; 35:351–363 11. Wilk KE, Arrigo CA, Andrews JR. Current con-



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APPENDIX 1: Muscles With Scapular Attachments Scapulothoracic group Serratus anterior Trapezius Pectoralis minor Rhomboid major Rhomboid minor Levator scapulae Latissimus dorsi Scapulohumeral group Rotator cuff Supraspinatus Infraspinatus Subscapularis Teres minor Deltoid Long head of the biceps brachii Short head of the biceps brachii Coracobrachialis Teres major Triceps brachii

servative treatment of ipsilateral fractures of the scapula and clavicle. J Trauma 1997; 42:239–242 69. Oh W, Jeon IH, Kyung S, Park C, Kim T, Ihn C. The treatment of double disruption of the superior shoulder suspensory complex. Int Orthop 2002; 26:145–149 70. Lecoq C, Marck G, Curvale G, Groulier P. Triple fracture of the superior shoulder suspensory complex [in French]. Acta Orthop Belg 2001; 67:68–72 71. Williams GR Jr, Naranja J, Klimkiewicz J, Karduna A, Iannotti JP, Ramsey M. The floating shoulder: a biomechanical basis for classification and management. J Bone Joint Surg Am 2001; 83:1182–1187

APPENDIX 2: Relative Indications for Operative Management of Scapular Fractures Intraarticular fractures: glenoid fossa Displacement of at least 4 mm Articular surface fracture involving at least 20% Anterior rim fracture involving at least 25% of articular surface Posterior rim fracture involving at least 33% of articular surface Extension to medial scapular border Extraarticular fractures Coracoid process (isolated) Displacement of at least 10 mm Intraarticular extension Significant future biomechanical demands Acromion process (isolated) Displacement of at least 10 mm Painful nonunion Associated subacromial impingement Scapular neck Glenopolar angle up to 22° Lateral border offset of at least 10 mm Angulation of at least 40° Translation of at least 10 mm Superior shoulder suspensory complex At least two disruptions with displacement of at least 10 mm (Figures start on next page)

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Fig. 1—Drawing shows scapular anatomy. 1 = superior angle, 2 = medial border, 3 = neck, 4 = lateral border, 5 = inferior angle, 6 = coracoid process, 7 = glenoid fossa, 8 = body, 9 = acromion process, 10 = spine.

Scapular Fractures

A

B

D

C

Fig. 2—Scapular motion. A, Drawing shows protraction (solid arrow) and retraction (dashed arrow). B, Drawing shows downward rotation (solid arrow) and upward rotation (dashed arrow). C, Drawing shows anterior tilting (solid arrow) and posterior tilting (dashed arrow). D, Drawing shows external rotation (solid arrow) and internal rotation (dashed arrow).



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A

B

C

Fig. 3—Example measurements for scapular neck fracture. A, Coronal volume-rendered 3D CT image corresponding to anteroposterior radiograph shows measurement of glenopolar angle by tracing confluence of lines between superior-inferior glenoid pole axis and superior glenoid pole-inferior scapular angle axis. (Acromion is not shown.) B, Coronal volume-rendered 3D CT image corresponding to anteroposterior radiograph shows measurement of lateral border offset by tracing distance between lateral margins of superior and inferior scapular neck fracture fragments. C, Sagittal volume-rendered 3D CT image corresponding to scapular Y radiograph shows measurement of angulation for scapular neck fracture by tracing confluence of lines parallel to superior and inferior neck fragment cortexes. D, Sagittal volume-rendered 3D CT image corresponding to scapular Y radiograph shows measurement of translation for scapular neck fracture by tracing distance between superior and inferior fragment anterior cortexes.

D

A 498

B

Fig. 4—Two patients with intraarticular glenoid fractures. A, 28-year-old woman after motor vehicle collision. Grashey radiograph shows acute displaced intraarticular fracture from glenoid to inferior portion of neck (Ideberg type 2). B, 22-year-old woman after motor vehicle collision. Coronal volume-rendered 3D CT image shows acute comminuted and displaced fracture extending from glenoid articular surface to base of coracoid process (Ideberg type 3).



Scapular Fractures

A

B

C

Fig. 5—69-year-old man after fall from height. A, Anteroposterior radiograph shows acute anterior shoulder dislocation. B, Sagittal volume-rendered 3D CT image shows acute fracture and anterior displacement of large fracture fragment (arrow) from anterior glenoid rim (Ideberg type 1). C, Axial T2-weighted fat-saturated image shows acute displaced bony Bankart fracture at anterior inferior glenoid rim (long arrow) with associated bone marrow edema at posterolateral head (short arrow).

Fig. 6—Two patients with coracoid fractures. A, 28-year-old woman after falling off horse. Axillary radiograph shows acute fracture of coracoid process with anterior displacement of more than 1 cm (line). B, 23-year-old man after assault and seizure. Axial CT image shows acute displaced coracoid fracture (black arrow) and deep Hill-Sachs impaction fracture at posterolateral humeral head (white arrow) after anterior shoulder dislocation.

A

B

Fig. 7—Drawing shows anatomic classification of coracoid process fracture types. I = distal tip, II = midpoint, III = base, IV = superior body of scapula without intraarticular extension, V = superior body of scapula with intraarticular extension.


Ropp and Davis


Fig. 8—Two patients with acromion process fractures. A, 44-year-old man who presented for fracture follow-up 7 months after motorcycle collision. On axial CT image, there is no sign of healing at displaced acromion fracture site. B, 76-year-old man after fall. Anteroposterior radiograph shows acute fracture of acromion with inferior angulation (intersecting lines) concerning for associated rotator cuff impingement.

A

B

Fig. 9—48-year-old male pedestrian struck by motor vehicle. A, Anteroposterior radiograph shows displaced scapular neck (black arrow) and ipsilateral midshaft clavicle (long white arrow) fractures. Multiple ipsilateral displaced rib fractures are also present (short white arrows). B, Sagittal volume-rendered 3D CT image shows degree of scapular neck angulation and translation to greater detail. Degree of displacement and comminution of clavicle fracture is also better shown.

A

A 500

B

B

Fig. 10—36-year-old male pedestrian struck by motor vehicle. A, Anteroposterior radiograph shows acute scapular neck fracture (black arrow) and Rockwood type III acromioclavicular joint separation (white arrow). B, Sagittal volume-rendered 3D CT image shows degree of scapular neck angulation in greater detail.



Scapular Fractures

A

B

Fig. 11—42-year-old man after fall from ladder. A, Oblique coronal volume-rendered 3D CT image shows acute displaced acromion and coracoid process fractures. Nondisplaced acute fractures are also present at base of coracoid process and scapular body. B, Sagittal volume-rendered 3D CT image shows associated intraarticular comminuted glenoid fracture with significant displacement.

F O R YO U R I N F O R M AT I O N

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