Superior Labral Anteroposterior Lesions of the Shoulder: Part 1, Anatomy and Anatomic Variants

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1 Musculoskeletal Imaging Review Modarresi et al. SLP Lesions of the Shoulder Musculoskeletal Imaging Review CME SM SLP Lesions of the Shoulder FOCUS ON: Shahla Modarresi 1 Daria Motamedi 2 Cecilia Matilda Jude 3 Modarresi S, Motamedi D, Jude CM Keywords: glenoid labrum, MR arthrogram, MRI, overhead athletes, shoulder pain, SLP, sports medicine, superior labral anteroposterior tear DOI: /JR Received February 1, 2010; accepted without revision October 13, Department of Imaging, Musculoskeletal Section, West Los ngeles V Medical Center, Wilshire lvd, Los ngeles, C ddress correspondence to S. Modarresi (shahlamodarresi@yahoo.com). 2 Department of Imaging, Cedars-Sinai Medical Center, Los ngeles, C. 3 Department of Imaging, Olive View UCL Medical Center, Sylmar, C. CME/SM This article is available for CME/SM credit. See for more information. JR 2011; 197: X/11/ merican Roentgen Ray Society Superior Labral nteroposterior Lesions of the Shoulder: Part 1, natomy and natomic Variants OJECTIVE. The objectives of this article are to provide a pictorial review of labral anatomy and physiology, with particular attention to commonly seen anatomic variants and pitfalls, and to present standard imaging techniques and approaches to MRI interpretation to facilitate diagnosis and treatment of superior labral anteroposterior (SLP) lesions. CONCLUSION. Imaging plays an important role in the diagnosis of SLP tears. Knowledge of glenolabral anatomy, related structures and variants, proper imaging techniques, and a systematic approach to MRI interpretation is important in the diagnosis and treatment planning of the 10 types of SLP lesions. rthroscopy offers a means for definitive diagnosis. S uperior labral anteroposterior (SLP) lesions are a common cause of chronic shoulder pain and instability in throwing athletes. SLP lesion is an abnormality of the superior labrum, which typically originates at the site of attachment of the long head of the biceps tendon but can extend to the anterior or posterior portion of the labrum and to adjacent structures. These lesions were first described in individuals who repetitively perform overhead arm motions, such as baseball pitchers, swimmers, tennis players, and volleyball players. However, SLP tears also present as a result of an acute traumatic event, such as a fall onto an outstretched hand or a shoulder dislocation. Superior glenoid labral tears were first described by ndrews and Carson [1] in 1984; subsequently, the term SLP tear was introduced by Snyder et al. [2] in 1990 who identified four types of tears on the basis of arthroscopic evaluation. This entity has increasingly been recognized in both the orthopedic and radiologic literature [3 6]. Classification of SLP lesions soon expanded with the addition of three types by Maffet et al. in 1995 [7] and two more by Resnick et al. in 1999 (Resnick D, unpublished data). Soon thereafter, the 10th type of SLP tear was introduced by eltran et al. in 2000 (presented at the 2000 annual meeting of the Radiological Society of North merica). The arthroscopic prevalence of SLP lesions in a population with shoulder pain ranges from 3.9% to 11.8% [2, 7 9]. ecause the clinical presentation of SLP lesions is nonspecific, MRI after intraarticular contrast administration plays an important role in the diagnosis of SLP lesions [10, 11]. rthroscopy remains the gold standard for confirmation of the diagnosis and monitoring treatment response. The purpose of this article is to review the anatomy and anatomic variants of the capsulolabral complex of the glenohumeral joint and to present an MRI approach to diagnosis. natomy of the Glenoid Labrum and Related Structures natomy of the Glenoid Labrum and iceps Tendon Knowledge of the normal anatomy and physiology of the glenoid labrum is important for understanding the pathogenesis of labral tears. The labrum is a ring of fibrocartilaginous tissue that surrounds the glenoid rim. It functions to increase the depth of the glenoid cavity and provides stability and shock absorption to the shoulder joint. On coronal sections, the labrum commonly appears triangular, but it may also be round, crescent shaped, or blunted [11]. The superior portion of the labrum can be mobile and lax, a variant that is recognizable with arthroscopy [12]. The superior and anterosuperior 596 JR:197, September 2011

2 SLP Lesions of the Shoulder regions of the labrum have the poorest blood supply, which slows the healing process of SLP tears in this distribution [13]. The labrum serves as the site of attachment for the shoulder capsule, the long head of the biceps tendon, and the glenohumeral ligaments. The long head of the biceps tendon attaches both to the superior glenoid and to the superior labrum [13], with approximately 50% of the biceps tendon fibers arising from the superior glenoid labrum and the remainder from the supraglenoid tubercle. The biceps tendon then courses through the rotator interval and extends inferiorly within the bicipital groove of the humerus (Fig. 1). Four types of proximal biceps tendon attachment in relation to the glenoid labrum have been described [13]. In type I, the entire biceps tendon attaches to the posterior labrum; in type II, most of the biceps tendon fibers attach to the posterior labrum, with only a small portion connecting to the anterior labrum; in type III, the contributions of biceps fibers to the anterior labrum and posterior labrum are equal; and in type IV, most of the fibers attach to the anterior labrum, leaving only a small contribution to the posterior labrum [13]. In most individuals, the biceps attachment to the labrum is posterior, with type I and type II attachment types occurring in approximately 55% of individuals, followed by type III in 37%, and type IV in only 8%. For purposes of anatomic localization of SLP lesions, the glenoid is compared with the face of a clock, being divided into time zones: The area from 11- to 1-o clock is the superior aspect of the glenoid; 1- to 3-o clock, the anterosuperior aspect; 3- to 5-o clock, the anteroinferior aspect; 5- to 7-o clock, the inferior aspect; 7- to 9-o clock, the posteroinferior aspect; and 9- to 11-o clock, the posterosuperior aspect [3, 4] (Fig. 2). The clock face is applied in such a way that, by convention, the 3-o clock position is anterior in the sagittal imaging plane in the right and left shoulders [3]. natomy of the Rotator Interval The rotator interval is a triangular space in the anterior shoulder that is demarcated superiorly by the supraspinatus tendon and inferiorly by the subscapularis tendon. The base of the triangle is at the base of the coracoid process, and the apex is at the transverse ligament over the bicipital groove [14]. There are three important anatomic structures traversing the rotator interval: the long head of the biceps tendon, the superior glenohumeral ligament, and the coracohumeral ligament. These structures blend anteriorly in the rotator interval and have overlapping functions (Fig. 3). The coracohumeral ligament arises from the coracoid process as a broad ligament and divides distally into two major bands. The larger lateral band inserts on the greater tuberosity and the anterior border of the supraspinatus tendon. The smaller medial band crosses over the intraarticular biceps tendon and inserts on the lesser tuberosity, the superior fibers of the subscapularis tendon, and the transverse ligament. The superior glenohumeral ligament originates from the supraglenoid tubercle, blends distally with the coracohumeral ligament, and inserts on the lesser tuberosity [14]. The biceps pulley system is an important component of the rotator interval, stabilizing the long head of the biceps tendon as it passes through the interval between the supraspinatus tendon and subscapularis tendon before entering the intertubercular groove [14, 15]. The biceps pulley system is composed of the medial band of the coracohumeral ligament, the superior glenohumeral ligament, the transverse humeral ligament, and fibers from the subscapularis tendon. These structures form a sling of tissue around the long head of the biceps tendon and act as a pulley, thereby preventing subluxation or dislocation of the biceps tendon [14] (Fig. 3). Injuries to this tendinous-ligamentous sling are termed biceps pulley lesions. natomy of the Glenohumeral Ligaments The glenohumeral ligaments are focal thickenings of the joint capsule, forming the superior, middle, and inferior glenohumeral ligaments, that are important stabilizers of the shoulder joint (Fig. 4). The anatomy of these ligaments varies significantly; the more common variants are thinning, thickening, or absence of a ligament or a common origin of the superior and middle glenohumeral ligaments [16]. Superior glenohumeral ligament The superior glenohumeral ligament originates from the supraglenoid tubercle, anterior to the origin of the biceps tendon. The superior glenohumeral ligament may share its origin with the biceps tendon or the middle glenohumeral ligament and extends inferiorly to the lesser tuberosity of the humerus [17]. The most important function of the superior glenohumeral ligament is to stabilize the long head of the biceps tendon in its intraarticular course, thereby preventing posterior and inferior instability. The superior glenohumeral ligament is best visualized on axial MR arthrograms (Fig. 5). Middle glenohumeral ligament The middle glenohumeral ligament arises from the supra glenoid tubercle and the anterosuperior labrum, inserting medial to the lesser tuberosity of the humerus [17]. The middle glenohumeral ligament shows the most variation of all the glenohumeral ligaments in configuration, size, shape, and attachment. It may be poorly defined or absent in up to 30% of patients, or it may appear thickened and cordlike and the anterosuperior labrum may be absent; the latter variant is called uford complex [18]. The middle glenohumeral ligament limits external rotation at 45 of abduction and plays an important role in resisting inferior translation of the humerus. The middle glenohumeral ligament is best visualized on sagittal or axial MR arthrograms (Fig. 6). Inferior glenohumeral ligaments The inferior glenohumeral ligaments, also called the inferior glenohumeral ligament complex, originate from the glenoid labrum and attach to the inferior anatomic neck of the humerus. The inferior glenohumeral ligament complex consists of two bands, anterior and posterior, arising from the anteroinferior and posteroinferior glenoid labrum, respectively, along with the intervening axillary recess [17] (Fig. 7). The anteroinferior band of the inferior glenohumeral ligament provides anteroinferior stability and functions as the primary restraint to anterior shoulder dislocation. The posteroinferior band limits posterior translation of the humerus during abduction and external rotation. MRI and MR rthrography of the Superior Labrum: Pitfalls and natomic Variants Imaging plays a significant role in the diagnosis of labral lesions. Radiographs of the shoulder typically show normal findings in patients with isolated labral tears, but abnormalities may be seen in the presence of associated injuries, such as a Hill-Sachs defect and bony ankart lesion. MRI is the imaging modality of choice for evaluating the bicipital-labral complex and the soft tissues around the shoulder. MR arthrography, which entails intraarticular instillation of dilute gadolinium, is superior to conventional MRI in evaluating the glenoid labrum and glenohumeral ligaments [19, 20] and is the imaging gold standard for assessing young athletic patients JR:197, September

3 Modarresi et al. with chronic shoulder instability and suspected SLP lesions. The indications for MR arthrography include persistent shoulder pain, mechanical symptoms, or a history of trauma complemented by physical examination findings that suggest intraarticular abnormalities. For diagnosing SLP tears, 1.5-T MR arthrography is highly accurate, with a documented sensitivity range of % and a specificity range of 71 98% [10, 21 24]. In recent studies, investigators have reported the performance of 3-T MRI and MR arthrography in the evaluation of labral abnormalities [25, 26]. In a study evaluating MR interpretations with respect to results obtained from arthroscopy, Magee and Williams [26] found a sensitivity of 90% and a specificity of 100% using 3-T MRI for the detection of SLP tears. Magee [25] further compared 3-T MRI and MR arthrography with arthroscopy in the evaluation of shoulder injuries including SLP tears. In this second study [25], the sensitivity and specificity for detecting SLP tears was 83% and 99%, respectively, for MRI and 98% and 99% for MR arthrography. The results of these studies showed that 1.5-T MRI had an accuracy similar to that of 3-T MRI but that 3-T MR arthrography had an increased accuracy compared with 3-T MRI in the diagnosis of SLP tears. When MR arthrography is contraindicated, CT arthrography can be used. The sensitivity and specificity of 16-MDCT arthrography for detecting SLP lesions are comparable with those of MR arthrography, with values of 86% and 90%, respectively [27]. The MR arthrography technique involves intraarticular injection of contrast material under fluoroscopic guidance via an anterior approach using a 20- to 22-gauge needle. Initially, a small amount of iodinated contrast medium is injected into the shoulder joint to verify needle position. Subsequently, ml of 1:200 dilution consisting of gadolinium-based contrast material and normal saline is introduced. MRI is performed within 15 minutes after intraarticular injection on a 1.5-T system using a dedicated shoulder coil. Routine sequences include coronal oblique, sagittal oblique, and axial T1-weighted fatsaturated spin-echo sequences (TR range/ TE range, /14 16) and a coronal oblique T2-weighted fast spin-echo sequence ( /90 115). The axial and coronal planes are the most valuable planes for the evaluation of SLP lesions, whereas sagittal images are helpful for the detection of displaced fragments in bucket-handle and flap tears and for mapping lesions in time zones [28]. The abducted and externally rotated position adds sensitivity for the detection of labral tears by stretching the anterior supporting structures [29]. The labrum is typically triangular but may be round, crescentic, or blunted with smooth margins. It normally appears as a lowsignal structure on all MR sequences [11] (Fig. 8). Increased intralabral signal in older individuals may not be pathologic when the morphology of the labrum is normal and could represent degenerative change [4]. Several pitfalls or anatomic variants may be seen on MRI of the glenoid labrum. Two technical sources of pitfalls on MRI are the magic angle effect and partial volume averaging, which can create an intralabral signal. The magic angle phenomenon appears as an increased intralabral signal in the posterosuperior aspect of the glenoid labrum on MRI sequences with a short TE and may be misdiagnosed as a tear [30]. Partial volume averaging of the posterosuperior labrum with the glenohumeral ligaments can be distinguished from a tear by following anatomic structures on adjacent images. nother MRI pitfall may be seen along the superior half of the glenoid, at the transitional area from the fibrocartilage of the labrum to the hyaline cartilage of the glenoid [4]. This transitional zone may appear as an intermediate signal between the labrum and the glenoid without extension into the labrum and may show no contrast filling on MR arthrography. natomic variants in the attachment and morphology of the labrum and glenohumeral ligaments are commonly seen between the 11- and 3-o clock positions and include sublabral recess, sublabral foramen, uford complex, and mobile glenoid labrum. detailed knowledge of these anatomic variations is especially crucial for adequate diagnosis and treatment planning because this area of the labrum is a common site of labral abnormalities. Furthermore, these variants are associated with a higher incidence of SLP lesions [31 33]. The sublabral recess or sulcus is the most common anatomic variant of the labrum, occurring in up to 73% of individuals, and is seen more frequently in older patients [34 36]. The sublabral recess is located at the 11- to 1-o clock position and represents a sulcus between the biceps-labral complex and the superior glenoid cartilage at the site of attachment of the long head of the biceps tendon to the labrum and glenoid (Fig. 9). The sublabral recess has smooth margins, measuring up to 2 mm in width, and extends medially between the superior labrum and bony glenoid [4]. Three types of labral attachments to the glenoid have been described on the basis of the depth of the sublabral recess: Type I entails a firm attachment of the labrum to the glenoid without a recess; type II, a small recess between the labrum and the glenoid rim; and type III, a deeper sulcus that can reach up to 5 mm in depth [34]. type III labral attachment may be difficult to differentiate from a SLP II lesion [11]; furthermore, a sublabral recess can lead to a SLP tear with continued overuse. Extension of the sublabral recess posterior to the biceps tendon insertion on the labrum has been described in several studies, with prevalence ranging from to 31% to 91% [35, 37]. sublabral recess may be contiguous with a sublabral foramen [11]. MR arthrography shows a high sensitivity in detecting a sublabral recess with values ranging from 81% to 92% and a high specificity, with a reported value of 100% [35, 36]. Importantly, studies have shown that MR arthrography is highly accurate in differentiating a sublabral recess from a SLP tear [34, 37]. The sublabral recess should follow the curve of the glenoid cartilage with a normal adjacent labrum. lthough not used as a standard procedure in evaluating joint lesions, CT arthrography, when performed on a 16-MDCT unit, shows a high sensitivity and specificity, 84% and 100%, respectively, in detecting a sublabral recess and therefore can be used when MRI is contraindicated [35]. dditionally, MDCT arthrography has shown an 81% accuracy rate in the evaluation of the anteroposterior extension of sublabral recess. sublabral foramen or hole is an anatomic variant located at the 1- to 3-o clock position that presents as a separation of the anterosuperior labrum from the glenoid, anterior to the long head of the biceps tendon attachment (Fig. 10). It is seen in 3 15% of individuals [18, 31, 35, 38]. sublabral foramen may coexist with a sublabral recess [11] or with a uford complex [18]. MR arthrography is valuable in differentiating a sublabral foramen from a SLP tear [34, 37]. Notably, a sublabral foramen has a smooth margin and does not extend to the bicipitallabral complex. uford complex is an anatomic variant that occurs in 1.5% of individuals. It presents as a thickened, cordlike middle glenohumeral ligament without an anterosuperior labrum [18] (Fig. 11). The thickened middle 598 JR:197, September 2011

4 SLP Lesions of the Shoulder glenohumeral ligament attaches directly to the anterosuperior glenoid and may be confused with a labral detachment. Distinguishing a uford complex from a labral tear is crucial because inadvertent suture of the middle glenohumeral ligament to the glenoid can result in surgical repair failure and loss of range of motion [18]. mobile glenoid labrum loosely attached in the superior aspect of the glenoid is seen in up to 25% of patients, especially those older than 30 years. This variant may be distinguished from a superior labral tear by the presence of an intact labrum, articular cartilage, and a smooth superior glenoid tubercle and no evidence of associated trauma. rthros copy is useful in confirming the diagnosis. However, repair is undertaken only in patients who present with torn fibers and hypermobile attachment of the biceps tendon [12]. Conclusions Knowledge of the anatomy of the glenoid labrum, biceps tendon, and glenohumeral ligaments and of variants is paramount to understanding abnormalities such as SLP lesions and is critical for properly interpreting imaging examinations, such as MRI and MR arthrography. Clinical presentation of patients with SLP lesions is nonspecific and MR arthrography is the standard modality used for imaging diagnosis and classification. cknowledgment We thank Patricia Vetter, biomedical illustrator (Los ngeles, C), for providing the anatomic illustrations. References 1. ndrews JR, Carson WG. The arthroscopic treatment of glenoid labrum tears in the throwing athlete. Orthop Trans 1984; 8:44 2. Snyder SJ, Karzel RP, Del Pizzo W, et al. SLP lesions of the shoulder. rthroscopy 1990; 6: Mohana-orges V, Chung C, Resnick D. Superior labral anteroposterior tear: classification and diagnosis on MRI and MR arthrography. JR 2003; 181: Chang D, Mohana-orges, orso M, Chung C. SLP lesions: anatomy, clinical presentation, MR imaging diagnosis and characterization. Eur J Radiol 2008; 68: Gregush RV, Snyder SJ. Superior labral repair. Sports Med rthrosc 2007; 15: edi, llen. Superior labral lesions anterior to posterior: evaluation and arthroscopic management. Clin Sports Med 2008; 27: Maffet MW, Gartsman GM, Moseley. Superior labrum-biceps tendon complex lesions of the shoulder. m J Sports Med 1995; 23: Snyder SJ, anas MP, Karzel RP. n analysis of 140 injuries to the superior glenoid labrum. J Shoulder Elbow Surg 1995; 4: Handelberg F, Willems S, Shahabpour M, Huskin JP, Kuta J. SLP lesions: a retrospective multicenter study. rthroscopy 1998; 14: Waldt S, urkart, Lange P, Imhoff P, Rummeny EJ, Woertler K. Diagnostic performance of MR arthrography in the assessment of superior labral anteroposterior lesions of the shoulder. JR 2004; 182: De Maeseneer M, Van Roy F, Lenchik L, et al. CT and MR arthrography of the normal and pathologic anterosuperior labrum and labral-bicipital complex. RadioGraphics 2000; 20:S67 S Davidson P, Rivenburgh DW. Mobile superior glenoid labrum: a normal variant or pathologic condition? m J Sports Med 2004; 32: Vangsness CT Jr, Jorgenson SS, Watson T, Johnson DL. The origin of the long head of the biceps from the scapula and glenoid labrum: an anatomical study of 100 shoulders. J one Joint Surg r 1994; 76: Morag Y, Jacobson J, Shields G, et al. MR arthrography of rotator interval, long head of the biceps brachii, and biceps pulley of the shoulder. Radiology 2005; 235: Grainger J. Internal impingement syndromes of the shoulder. Semin Musculoskelet Radiol 2008; 12: eltran J, encardino J, Mellado J, Rosenberg ZS, Irish RD. MR arthrography of the shoulder: variants and pitfalls. RadioGraphics 1997; 17: De Maeseneer M, Van Roy P, Shahabpour M. Normal MR imaging anatomy of the rotator cuff tendons, glenoid fossa, labrum, and ligaments of the shoulder. Radiol Clin North m 2006; 44: Williams MM, Snyder SJ, uford D Jr. The uford complex: the cord-like middle glenohumeral ligament and absent anterosuperior labrum complex a normal anatomic capsulolabral variant. rthroscopy 1994; 10: Magee T, Williams D, Mani N. Shoulder MR arthrography: which patient group benefits most? JR 2004; 183: Chandnani VP, Yeager TD, Deerardino T, et al. Glenoid labral tears: prospective evaluation with MRI imaging, MR arthrography, and CT arthrography. JR 1993; 161: pplegate GR, Hewitt M, Snyder SJ, Watson E, Kwak S, Resnick D. Chronic labral tears: value of magnetic resonance arthrography in evaluating the glenoid labrum and labral-bicipital complex. rthroscopy 2004; 20: Jee WH, McCauley TR, Katz LD, Matheny JM, Ruwe P, Daigneault JP. Superior labral anterior posterior (SLP) lesions of the glenoid labrum: reliability and accuracy of MR arthrography for diagnosis. Radiology 2001; 218: Holzapfel K, Waldt S, ruegel M, et al. Inter- and intraobserver variability of MR arthrography in the detection and classification of superior labral anterior posterior (SLP) lesions: evaluation in 78 cases with arthroscopic correlation. Eur Radiol 2010; 20: encardino JT, eltran J, Rosenberg ZS, et al. Superior labrum anterior-posterior lesions: diagnosis with MR arthrography of the shoulder. Radiology 2000; 214: Magee T. 3-T MRI of the shoulder: is MR arthrography necessary? JR 2009; 192: Magee TH, Williams D. Sensitivity and specificity in detection of labral tears with 3.0-T MRI of the shoulder. JR 2006; 187: Oh JH, Kim JY, Choi J, Kim WS. Effectiveness of multidetector computed tomography arthrography for the diagnosis of shoulder pathology: comparison with magnetic resonance imaging with arthroscopic correlation. J Shoulder Elbow Surg 2010; 19: Monu JUV, Pope TL Jr, Chabon SJ, et al. MR diagnosis of the superior labral anterior posterior (SLP) injuries of the glenoid labrum: value of routine imaging without intraarticular injection of contrast material. JR 1994; 163: orrero CG, Casagranda U, Towers JD, radley JP. Magnetic resonance appearance of posterosuperior labral peel back during humeral abduction and external rotation. Skeletal Radiol 2010; 39: Sasaki T, Yodono H, Prado GL, et al. Increased signal intensity in the normal glenoid labrum in MR imaging: diagnostic pitfalls caused by the magic-angle effect. Magn Reson Med Sci 2002; 1: Rao G, Kim TK, Chronopoulos E, McFarland EG. natomical variants in the anterosuperior aspect of the glenoid labrum: a statistical analysis of seventy-three cases. J one Joint Surg m 2003; 85: Ilahi O, Labbe MR, Cosculluela P. Variants of the anterosuperior glenoid labrum and associated pathology. rthroscopy 2002; 18: ents RT, Skeete KD. The correlation of the uford complex and SLP lesions. J Shoulder Elbow Surg 2005; 14: Smith DK, Chopp TM, ufdemorte T, Witkowski EG, Jones RC. Sublabral recess of the superior glenoid labrum: study of cadavers with conventional nonenhanced MR imaging, MR arthrography, anatomic dissection, and limited histologic examination. Radiology 1996; 201: JR:197, September

5 Modarresi et al. 35. Waldt S, Metz S, urkart, et al. Variants of the superior labrum and labro-bicipital complex: a comparative study of shoulder specimens using MR arthrography, multi-slice CT arthrography and anatomical dissection. Eur Radiol 2006; 16: Kreitner KF, otchen K, Rude J, et al. Superior labrum and labral-bicipital complex: MR imaging with pathologic-anatomic and histologic correlation. JR 1998; 170: Jin W, Ryu KN, Kwon SH, et al. MR arthrography in the differential diagnosis of type II superior labral anteroposterior lesion and sublabral recess. JR 2006; 187: Stoller DW. MR arthrography of the glenohumeral joint. Radiol Clin North m 1997; 35: Fig. 1 natomy of glenoid labrum and biceps tendon., Schematic representation of glenoid labrum, biceps tendon, and glenohumeral ligaments. This schematic of glenohumeral joint in sagittal view shows small glenoid socket. Labrum is seen as fibrocartilaginous ring surrounding glenoid rim. iceps tendon attaches to superior aspect of glenoid labrum. Glenohumeral ligaments and rotator cuff muscles are also depicted. = acromion, C = coracoid process, SS = supraspinatus muscle, IS = infraspinatus muscle, T = teres minor, T = biceps tendon, SGHL = superior glenohumeral ligament, MGHL = middle glenohumeral ligament, IGHLC = inferior glenohumeral ligament complex, G = glenoid., Coronal T1 fat-suppressed MR arthrogram of shoulder of 35-year-old man shows normal glenoid labrum (arrow). Labrum appears triangular and smooth and shows dark signal in all imaging sequences. G = glenoid, HH = humeral head. C, Coronal T1 fat-suppressed MR arthrogram of shoulder of 40-year-old woman shows biceps tendon attachment on glenoid tubercle (arrow) and superior labrum. HH = humeral head, G = glenoid, arrowhead = biceps tendon within bicipital groove. C Fig. 2 Glenoid labral division for localization of labral abnormalities. Glenoid labrum is compared with face of clock: 11- to 1-o clock position is superior aspect; 1- to 3-o clock, anterosuperior aspect; 3- to 5-o clock, anteroinferior aspect; 5- to 7-o clock, inferior aspect; 7- to 9-o clock posteroinferior aspect; and 9- to 11-o clock, posterosuperior aspect. Clock face is applied in such way that, by convention, 3-o clock position is always anterior in sagittal imaging plane in right and left shoulders. 600 JR:197, September 2011

6 SLP Lesions of the Shoulder Fig. 4 Glenohumeral ligaments. Schematic representation shows three glenohumeral ligaments: superior glenohumeral ligament (SGHL), middle glenohumeral ligament (MGHL), and inferior glenohumeral ligament complex (IGHLC). T = biceps tendon, G = glenoid. C Fig. 5 Normal superior glenohumeral ligament. xial T1 fat-suppressed MR arthrogram of shoulder of 40-year-old man shows normal appearance of superior glenohumeral ligament (arrow). HH = humeral head, G = glenoid. D Fig. 3 natomy of rotator interval., Schematic representation of rotator interval and structures that cross it including long head of biceps tendon and superior glenohumeral ligament (SGHL). Numbers show time zone divisions used to localize labral abnormalities. C = coracoid process, SS = supraspinatus muscle, IS = infraspinatus muscle, T = teres minor, SC = subscapularis muscle, T = biceps tendon, MGHL = middle glenohumeral ligament, IGHLC = inferior glenohumeral ligament complex, G = glenoid., Sagittal oblique T1 fat-suppressed MR arthrogram of 30-year-old man shows rotator interval (triangle) as triangular space in anterior shoulder demarcated by supraspinatus muscle and tendon (SS), subscapularis muscle and tendon (SC), and coracoid process (C). iceps tendon (arrow) is seen traversing rotator interval. IS = infraspinatus muscle, G = glenoid. C, Sagittal T1 fat-suppressed MR arthrogram of shoulder of 30-year-old man shows origin of long head of biceps tendon (white arrow) enveloped by sling formed by coracohumeral and superior glenohumeral ligaments (black arrow). SS = supraspinatus muscle, C = coracoid process. D, xial T1 fat-suppressed MR arthrogram of shoulder of 32-year-old man shows proximal portion of coracohumeral ligament (white arrow), superior glenohumeral ligament (arrowhead), and adjacent long head of biceps tendon (black arrow). HH = humeral head, G = glenoid. Fig. 6 Normal middle glenohumeral ligament. xial STIR MR image of shoulder of 37-year-old man shows normal middle glenohumeral ligament (arrow) anterior to glenoid labrum. Joint effusion is seen. HH = humeral head, G = glenoid. JR:197, September

7 Modarresi et al. Fig. 7 Normal inferior glenohumeral ligament complex., Coronal T1 fat-suppressed MR arthrogram of 31-year-old man shows normal inferior glenohumeral ligament (arrow). HH = humeral head, G = glenoid., Sagittal T1 fat-suppressed MR arthrogram of shoulder of 31-year-old man shows anterior and posterior bands of normal inferior glenohumeral ligament complex (arrows) with intervening axillary pouch (P). HH = humeral head. Fig. 8 Normal superior labrum., Coronal STIR MR image of shoulder of 65-year-old man shows normal triangular appearance of superior labrum (arrow) attached to superior glenoid rim. Degenerative cysts of humeral head (HH) and glenoid are seen. G = glenoid., xial gradient-echo MR image of shoulder of 45-year-old man shows normal anterior and posterior labrum (arrows). HH = humeral head, G = glenoid. Fig. 9 Normal sublabral recess., Schematic representation of normal glenoid labrum, biceps tendon (T), and sublabral recess in coronal plane. Sublabral recess follows contour of glenoid cartilage (arrow). G = glenoid, HH = humeral head, arrowhead = superior labrum., Coronal oblique T1 fat-suppressed MR arthrogram of shoulder of 33-year-old man shows normal sublabral recess (arrow) with smooth margins and extending medially between superior labrum and bony glenoid. HH = humeral head, G = glenoid. 602 JR:197, September 2011

8 C SLP Lesions of the Shoulder D Fig. 10 Sublabral foramen., Schematic representation of sublabral foramen (arrow), anatomic variant, shows separation of anterosuperior labrum from glenoid at 1-o clock position, which reattaches to glenoid cartilage at 3-o clock position. T = biceps tendon, SGHL = superior glenohumeral ligament, MGHL = middle glenohumeral ligament, IGHLC = inferior glenohumeral ligament complex, G = glenoid., Sagittal STIR image of shoulder of 40-year-old man shows separation of anterosuperior labrum from glenoid at 1-o clock, which reattaches to glenoid cartilage at 3-o clock. These findings are consistent with sublabral foramen. Numbers show time zone divisions used to localize labral abnormalities. G = glenoid, SS = supraspinatus muscle, IS = infraspinatus muscle, C = coracoid process, arrow = sublabral foramen. C and D, xial T1 fat-suppressed MR arthrograms of shoulder of 38-year-old man show separation (arrow, C) of anterosuperior labrum from glenoid between 1- and 3-o clock positions, which reattaches to glenoid cartilage (arrow, D). These findings are consistent with sublabral foramen. Middle glenohumeral ligament (arrowhead, C) is also seen. HH = humeral head, G = glenoid. Fig. 11 uford complex., Schematic representation of uford complex, anatomic variant, shows absence of anterosuperior labrum (arrow) and thickening of middle glenohumeral ligament (MGHL). T = biceps tendon, SGHL = superior glenohumeral ligament, IGHLC = inferior glenohumeral ligament complex, G = glenoid., xial T2 fat-suppressed MR image of shoulder of 45-year-old man shows thickened middle glenohumeral ligament (arrow) and that anterosuperior labrum is absent. These findings are consistent with uford complex. HH = humeral head, G = glenoid. FOR YOUR INFORMTION The Self-ssessment Module accompanying this article can be accessed via at the article link labeled CME/SM. The merican Roentgen Ray Society is pleased to present these Self-ssessment Modules (SMs) as part of its commitment to lifelong learning for radiologists. Each SM is composed of two journal articles along with questions, solutions, and references, which can be found online. Read each article, then answer the accompanying questions and review the solutions online. fter submitting your responses, you'll receive immediate feedback and benchmarking data to enable you to assess your results against your peers. Continuing medical education (CME) and SM credits are available in each issue of the JR and are free to RRS members. Not a member? Call (from the U.S. or Canada) or to speak to an RRS membership specialist and begin enjoying the benefits of RRS membership today! JR:197, September