On the humerus, the capsule attaches to its anatomical neck. The capsule remains lax to allow for mobility of the upper limb. The fact that these folds are in the nondependent position of the recess will help distinguish them from true loose bodies [7]. As for the tubercle of Assaki, the bare area of the glenoid may be mistaken for a cartilage ulceration. The rotator cuff allows the range of motion of the shoulder and protects and stabilizes the glenohumeral joint; it includes the muscles and tendons of the supraspinatus, infraspinatus, subscapularis and teres minor (Figures 2 and 3, additional material). Imaging of the Shoulder: Techniques and Applications (Medical Radiology / Diagnostic Imaging). are major limitations. There are two main recesses of the capsule, the subscapular recess and the axillary recess (Figure (Figure23).23). This wide ligament lies deep to, and blends, with the tendon of subscapularis muscle. The anterior band limits externalrotation of the arm, while the posterior band limits internalrotation. Intra-articular injection of iodine contrast material allows visualization of the capsulolabral structures. The dorsal aspect of the scapula is divided by the scapular spine into the supraspinous and infraspinous fossa where the supraspinatus and infraspinatus muscles attach respectively [3,6]. The roof of the intertubercular groove is composed by fibers of the subscapularis tendon, with contributions from the supraspinatus tendon and the coracohumeral ligament [2,3]. Glenohumeral joint (Articulatio glenohumeralis) -Yousun Koh. (, BLC. The https:// ensures that you are connecting to the The insertion area of the supraspinatus is located at the anteromedial part of the superior facet and is sometimes located at the most superior part of the lesser tuberosity (Figure 10, additional material) [17]. A bare area has also been described in the mid third of the glenoid cavity; this is an oval area denuded of cartilage, probably developmental and should be differentiated from true cartilage injury (Figures (Figures66 and and7)7) [6,9]. New York, NY: McGraw-Hill Education. The anterior capsular mechanism includes the anterior capsule, the glenohumeral ligaments, the synovial membrane and its recesses, the glenoid labrum, the subscapularis muscle and tendon, and the scapular periosteum. Instead, they are typically pseudocysts that communicate with the joint space and represent a normal variant (Figure (Figure3)3) [4,6]. The shoulder joint is well suited to evaluation by ultrasonography (US) because of its easy accessibility. Being a synovial joint, both articular surfaces are covered with hyaline cartilage. LHBT: long head of biceps tendon, SGHL: superior glenohumeral ligament, MGHL: middle glenohumeral ligament, IGHL: inferior glenohumeral ligament. The glenoid labrum was observed to be fibrocartilaginous, being more fibrous in its free margin. The shoulder joint is functionally and structurally complex and is composed of bone, hyaline cartilage, labrum, ligaments, capsule, tendons and muscles. When present, it appears as a straight thin line extending from the superior glenoid rim to the coracoid process on axial and sagittal images (Figure (Figure19)19) [14]. Laterally, it fuses with the posterior part of the rotator cable and fibers of the infraspinatus before these three structures jointly insert on the posterior facet of the greater tuberosity. Shoulder instability and dislocation occur when the shoulder capsule is stretched or torn, and/or when the labrum is detached from the glenoid. 7 ). Type 2 forms a small sulcus at the superior pole of glenoid. Jacob Mandell. The role of this bursa is to decrease frictional forces on the supraspinatus tendon and between the deltoid and the rotator cuff. The long head of the biceps tendon originates mostly from the supraglenoid tuberosity and partly from the superior labrum, having a common attachment with the superior glenohumeral ligament (Figures (Figures3,3, ,16).16). Hall, S. J. (A) On the axial T2 gradient echo weighted MR image, there is a slight flattening of the posteroinferior surface of the humeral head (arrow), which is a normal finding. At the superior labrum, fibers from the proximal origin of the long head of the biceps tendon blend with the labrum forming the biceps labral complex (BLC). This ligament originates on the posterosuperior part of the glenoid neck, medial to the labrum and the origin of the biceps tendon. Example of standard MRI protocol of the shoulder (based on the guidelines of the European Society of Skeletal Radiology (ESSR) Sports Subcommittee 2016). On arthroscopic images, the rotator cable appears as a fibrous transverse band surrounding the rotator crescent. The first is the rotator interval, an area of unreinforced capsule that exists between the subscapularis and supraspinatus tendons. The glenoid labrum is a fibrocartilaginous structure that attaches as a rim to the articular cartilage of the glenoid fossa and serves to deepen and increase the surface area of the glenoid. variants or glenoidal labrum. This review discusses the normal anatomy and anatomic variants of the glenoid labrum, articular cartilage, and glenohumeral ligaments. When the anterior capsular attachment is far from the glenoid margin (type III), the glenohumeral joint will be more unstable. CONCLUSION. The additional accessory movements of spin, roll and slide (glide) are also available within the glenohumeral joint. It corresponds to a synovial reflection medial to the superior edge of the glenoid rim at the biceps anchor, showing a normal defect of the attachment of the superior labrum to the superior glenoid cartilage. The attachment of the labrum to the bony edge of the glenoid was observed under light microscopy at each position and classified into two . Tubercle of Assaki. Recognition of normal thinning of peripheral humeral cartilage is essential in order to not mistaken it with posttraumatic or degenerative sequels. Read more, Physiopedia 2023 | Physiopedia is a registered charity in the UK, no. Normally, a delicate balance exists between the static and dynamic constraints in the shoulder. Both the anterior and posterior bands of the inferior glenohumeral ligament insert along the inferior aspect of the surgical neck of the humerus (Figures (Figures2323 and and24)24) [2,5]. The loose inferior capsule forms a fold when the arm is in the anatomical position. However, in the setting of a rotator cuff tear, a communication between the two spaces can develop. On sagittal CTA, the ligament appears as a T-shaped structure (thin white arrow, (B) Interposed between the long head of the biceps tendon posteriorly and the subscapularis tendon anteriorly. Adduction is produced by the pectoralis major, latissimus dorsi and teres major muscles. At the time the article was last revised Henry Knipe had the following disclosures: These were assessed during peer review and were determined to Sublabral recess (sublabral sulcus). Accessibility Two orthogonal views (anteroposterior and lateral views) of any bone or joint should be ideally obtained. Redundancy or type III is commonly observed for the posterior capsule. It is believed that the supraspinatus is important for movement initiation and early abduction, while the deltoid muscle is engaged from approximately 20 of abduction and carried the arm through to the full 180 of abduction. 2. It limits the space available to the rotator cuff tendons, the subacromial subdeltoid bursa, and the long head of the biceps (Figure 7, additional material). MR imaging of the shoulder with the arm in alternate positions has been advocated to better assess the integrity of specific labroligamentous structures. In most cases Physiopedia articles are a secondary source and so should not be used as references. The middle and, rarely, the anteroinferior glenohumeral ligaments may have glenoid attachment only through the superior labrum. 6 ). The teres major originates from the inferior lateral scapula and inserts onto the medial intertubercular humeral groove. The os acromiale is an accessory bone due to nonunion of ossification center during development (Figure (Figure9).9). : a fibrocartilaginous ligament forming the margin of the glenoid cavity of the shoulder joint that serves to broaden and deepen the cavity and gives attachment to the long head of the biceps brachii. Basic biomechanics (7th ed.). Bethesda, MD 20894, Web Policies It extends from the scapula to the humerus, enclosing the joint on all sides. Together with the coracobrachialis muscle tendon it originates from the coracoid process and is well demonstrated on axial sections [2,3,4,5,12]. The coracoacromial arch is an osteoligamentous arch that protects the humeral head and rotator cuff tendons from trauma. Instead the surrounding shoulder muscles and ligamentous structures offer the joint security; the capsule, ligaments and tendons of the rotator cuff muscles. 3. (A) Axial PD-weighted and (B) Sagittal fat-suppressed T1-weighted MR arthrographic images show a cord-like middle glenohumeral ligament (white arrow) associated with an absent anterior superior labrum (black arrow) mimicking a labral tear with normal posterior labrum. The long head of biceps tendon is secured within the bicipital groove by the transverse humeral ligament which passes between the greater and lesser tuberosities over the sheath of the tendon. Below the equatorial pole of the glenoid, the labrum becomes more rounded and smaller compared to superiorly where is more triangular in shape and larger. An external capsular circumferential ridge, 7-8 mm medial to the glenoid rim marks the attachment of the capsule. The latissimus dorsi originates from the spinous processes T6T12 and inserts into the medial intertubercular humeral groove. The rotator interval contains several important anatomical structures that contribute to the stability and normal function of the shoulder joint, including biceps tendon, coracohumeral ligament, superior glenohumeral ligament, rotator interval capsule, anterior fibers of the supraspinatus tendon, and superior fibers of the subscapularis tendon. Morphology varies regionally, especially in the superior and anterior region; these variants can sometimes be confused with pathological aspects. Two weak spots exist in this reinforced capsule. Cael, C. (2010). Between the greater and lesser tubercles of humerus, through which the tendon of the long head of biceps brachii passes. Coracohumeral ligament (thin arrow, A). Individually, each muscle has its own pulling axis that results in a certain movement (prime mover), while together they create a concavity compression. The shoulder is routinely imaged in neutral or slight external rotation. In contrast, the inferior labrum had a firm attachment through thick inelastic fibers and appeared as a firm immobile extension of the glenoid articular cartilage. Middle glenohumeral ligament. As described above, the coracohumeral ligament belongs to the anterior limb of the superior glenohumeral ligament complex. The sublabral foramen provides a communication between the glenohumeral joint and the subscapularis recess [7]. De Maeseneer, M, Pouliart, N, Boulet, C, Machiels, F, Shahabpour, M, Kichouh, M and De Mey, J. Inferior glenohumeral ligament. Springer. The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck, superior and medial to the glenoid fossa. Philadelphia, PA: Saunders. Knowledge of this variant is important not to mistaken it for a longitudinal split tear of the long head of the biceps tendon [4]. This bursa is bounded superiorly by the deltoid, acromion, and coracoacromial ligament and inferiorly by the rotator cuff, in particular the supraspinatus. Axial fat-saturated PD-weighted MR image shows focal elevation of the subchondral bone (arrow) in the mid third of the glenoid with focal thinning of overlying cartilage (arrowhead). At the time the article was created Henry Knipe had no recorded disclosures. In a recent publication, Schreinemachers and colleagues retrospectively compared the sensitivity and specificity of conventional arthrograms with single arthrographic series in ABER position. The subcoracoid bursa is located between the subscapularis muscle and the coracoid process, whereas the superior subscapular recess also known as the subscapular bursa is located between the anterior surface of the scapula and the subscapularis muscle (Figure 13, additional material). The supraspinatus muscle is best demonstrated on coronal oblique and axial sections as a thick, intermediate signal intensity structure tapering into a low signal intensity tendon that inserts into the superolateral aspect of the greater tuberosity. Significant internal rotation should be avoided for conventional MR imaging of the shoulder because it results in medial displacement of the joint capsule and contraction of the subscapularis tendon, both of which may obscure the subjacent anteroinferior labrum. The surface of the humeral head is three to four times larger than the surface of glenoid fossa, meaning that only a third of the humeral head is ever in contact with the fossa and labrum. The infraspinatus and teres minor muscles are best demonstrated on axial images as fusiform intermediate signal intensity structures parallel and inferior to the supraspinatus. Richards, J. In type III, the attachment is more than 1 cm medial to the labrum (Figure 8, additional material). The degree of rotation can be assessed by noting the position of the bicipital grove on axial images. On coronal oblique planes the relative location of the acromion to the distal clavicle can be better evaluated. Variant appearances of the middle glenohumeral ligament include absence of the middle glenohumeral ligament, a conjoint origin with either the superior glenohumeral ligament or inferior glenohumeral ligament, and a cord-like thickening of the middle glenohumeral ligament in combination with an absent anterosuperior labrum (Buford complex) [7]. According to Bigliani et al., the acromion is classified into three types: I (flat), II (curved), and III (hooked) (Figure (Figure8).8). Individuals with a larger cable are termed cable dominant. The rotator cable or ligamentum semicircular humeri is a band-like fibrous thickening that extends in an oblique direction from the coracohumeral ligament along the articular surface of the supraspinatus fibers anteriorly. The glenohumeral, or shoulder, joint is a synovial joint that attaches the upper limb to the axial skeleton. The suprascapular nerve traverses posteriorly the suprascapular fossa through the suprascapular notch. Mischaracterization of this finding as a superior labral anterior-posterior (SLAP) II tear is a potential diagnostic pitfall. The subscapularis lies anterior to the scapular body, whereas the supraspinatus, infraspinatus, and teres minor lie posteriorly from superior to inferior. The superior portion of the labrum is closely associated with the biceps tendon (Figure (Figure12).12). Edinburgh: Churchill Livingstone. A paramount advantage of US is the dynamic evaluation of shoulder impingement (i.e. Diagnosis of glenoid labral tears: a comparison between magnetic resonance imaging and clinical examinations. Focal thickening of the subchondral bone along the central aspect of the glenoid fossa is an additional normal variant termed the Ossaki tubercle. The scapulohumeral and thoracohumeral muscles are responsible for producing movement at the glenohumeral joint. Careers, Unable to load your collection due to an error. Grounded on academic literature and research, validated by experts, and trusted by more than 2 million users. The labrum is the attachment site for the shoulder ligaments and supports the ball . (, Labral bicipital sulcus. Recent work has expanded their anatomic description for the inferior but also superior glenohumeral ligament complexes. Type A and B labrum. The posteroinferior edge of the glenoid can have various shapes, including normal triangular, rounded or J shaped, and delta shaped (Figure 4, additional material). Unlike Bankart lesions and ALPSA lesions, they are uncommonly (20%) associated with shoulder instability 5.. Etiology.
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