Evaluation in the pediatric population using MR imaging has also shown some slight but significant variability in the location of the bare spot. Cortical bone has low signal intensity due to its high density and slow-moving protons. On coronal oblique planes the relative location of the acromion to the distal clavicle can be better evaluated. Of note, is that these muscles have a stronger action when acting to extend the flexed arm. The coracoacromial ligament is the ligamentous compound of the coracoacromial arch. Long head of biceps tendon | Radiology Reference Article - Radiopaedia.org It is a triangular area between the anterior border of the supraspinatus tendon and the superior border of the subscapularis tendon, ranging from the coracoid process to the biceps groove. The glenohumeral ligaments are fibrous reinforcements of the glenohumeral capsule and represent the most important passive stabilizers of the shoulder joint (Figure (Figure12).12). The suprascapular vessels project superior to this ligament. The articular surfaces of the acromioclavicular joint are covered with hyaline cartilage and in the central portion of the joint there is a fibrocartilaginous disc, usually incomplete. Vossen, JA and Palmer, WE. Focal thickening of the subchondral bone along the central aspect of the glenoid fossa is an additional normal variant termed the Ossaki tubercle. 2. Check for errors and try again. All rights reserved. (a) Normal anatomy; (b) Sublabral recess (sublabral sulcus); (c) Sublabral foramen (sublabral hole); (d) Buford complex. It acts to limit inferior translation and excessive externalrotation of the humerus. Here atKenhub, we offer you one of the greatest strategies to cement your knowledge, which involvescreating your own flashcards! Routine radiography, ultrasound, CT and MR imaging (conventional and arthrography) are the main diagnostic modalities used for diagnosis of abnormalities around the shoulder joint. The sublabral foramen can vary in extent from a focal detachment to involvement of the entire anterosuperior quadrant. Glenoid labrum Definition & Meaning | Merriam-Webster Medical Joints and ligaments of the upper limb: Anatomy | Kenhub Despite the continuity of labrum and most of the capsuloligamentous structures, distension of the joint may also result in the appearance of three distinct types of medial capsular attachment at the inferior attachment [14]. Labrum surrounds the glenoid fossa to extend the size of the socket while maintaining flexibility. Made of fibrocartilage, 3 mm thick and 4 mm wide (highly variable). Other investigators have since noted improved detection of anteroinferior labral pathology with the ABER technique. {"url":"/signup-modal-props.json?lang=us"}, Goel A, Knipe H, Weerakkody Y, et al. Subchondral cysts can be present within the humeral head and are normally found at the insertion of the supraspinatus and infraspinatus tendons. MRA using fat-saturated T1-weighted images and CTA in the axial plane show a cord-like middle glenohumeral ligament adjacent to an absent anterosuperior labrum. Glenoid Labrum Injury MRI - Medscape Conventional Magnetic Resonance Imaging (MRI) allows direct evaluation of rotator cuff muscles and tendons, medullary bone and neurovascular structures. A detached labrum can be repaired arthroscopically, with a small incision into which a scope and specialized tool is inserted. The glenoid articulates with the head of the humerus to form the glenohumeral joint. (2015). View detached labrum repair animation. Check for errors and try again. (A) Schematic illustration of the anterior ligaments of the shoulder. 6-3 ). the contents by NLM or the National Institutes of Health. 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. They require arthrographic technique (CTA and MRA) for more accurate assessment. It also serves as a primary attachment site for the GHLs, joint capsule, and long head of the biceps tendon. CT and MR arthrography of the normal and pathologic anterosuperior labrum and labral-bicipital complex, MR arthrography of the glenohumeral joint. Normally, a delicate balance exists between the static and dynamic constraints in the shoulder. The epiphysis shows fatty marrow, whereas the metaphysis and diaphysis show variable hematopoietic marrow, depending on the distribution of fatty to hematopoietic marrow [5]. In addition, some patients experience discomfort and/or a sensation of instability, particularly with the ABER position, and may not be able to tolerate this portion of the examination. They are also easily identified when an articular effusion is present [2,12]. The additional file for this article can be found as follows: Including normal MR images in the 3 planes and anatomical drawings and illustrations. Schematic illustration of the acromion shape as described by Bigliani. It may appear thickened and cordlike (Figure (Figure22),22), as in the Buford complex (Figures (Figures1212 and and15),15), or completely absent in 30% of healthy subjects. Glenohumeral (Shoulder) joint: Bones, movements, muscles | Kenhub It arises from the posterosuperior part of the glenoid neck, medial to the posterosuperior labrum and the origin of the long tendon of the biceps. 11 ). 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). SLAP Lesion: Part I. Pathophysiology and Diagnosis A cleavage tear is a gap running between the tendon fibers of the two strings (Figure 9, additional material) [18]. Song and colleagues introduced the adduction and internal rotation (ADIR) position at MR arthrography and evaluated its diagnostic performance compared with ABER and neutral position in the assessment of anterior inferior labral lesions. The groove between the two tuberosities along the anterior surface of the humerus is known as the intertubercular or bicipital groove and supports the long head of the biceps tendon. The greater tuberosity is located on the lateral aspect of the proximal humerus and is the site of insertion of the supraspinatus, infraspinatus, and teres minor tendons. SLAP Tear: What Is It, Causes, Symptoms and Treatment - Cleveland Clinic A variable deep notch or a physiological flattening in the humeral neck is located posterior to the greater tubercle and best visualized on axial images; this pitfall should not be mistaken for a Hill-Sachs impaction which is seen at or above the level of the coracoid process (Figure (Figure4)4) [4,5]. It is split into anterior and posterior bands, between which sits the axillary pouch. These smaller bursae generally do not communicate with the glenohumeral joint and include the infraspinatus, teres major, and pectoralis major bursae [1,4,5]. The articular cartilage of the humeral head is thicker centrally and thinner peripherally contrary to the glenoid articular cartilage which is relatively thinner centrally and thicker peripherally [7]. In type II, the capsule attaches on the glenoid neck within 1 cm of the labral base. That is usually the journal article where the information was first stated. The glenoid cavity or fossa forms a glenohumeral joint with the medial aspect of the humeral head (Figures 1 and 3, additional material). Similarly the subcoracoid bursae are found between the capsule and the coracoid process of the scapula. As described above, the coracohumeral ligament belongs to the anterior limb of the superior glenohumeral ligament complex. There are several bursae around the shoulder, the most important being the subacromial, subdeltoid, subscapular, and subcoracoid bursae (Figure 13, additional material). A focal well-demarcated articular cartilage defect at the central aspect of the glenoid termed the bare spot has been reported in the surgical and radiologic literature ( Fig. (Courtesy of Dr Henri Guerini). Quantitative analysis of attachment of the labrum to the glenoid fossa The labrum demonstrates considerable anatomic variability in its appearance, which may pose a diagnostic challenge to image interpretation. Individuals with a larger cable are termed cable dominant. It is lined by a synovial membrane [2]. LHBT: long head of biceps tendon, SGHL: superior glenohumeral ligament, MGHL: middle glenohumeral ligament, IGHL: inferior glenohumeral ligament. The axillary recess is located between the anterior and posterior bands of the inferior glenohumeral ligament [1]. The labrum is larger on the superior aspect than inferiorly. The soft tissues are poorly visualized compared to MRI. Indications for imaging of the shoulder have considerably increased in the last few years. As for the tubercle of Assaki, the bare area of the glenoid may be mistaken for a cartilage ulceration. The most common variants and pitfalls are related to the anterosuperior aspect of the shoulder joint. Both instability and pseudarthrosis can increase after acromioplasty [4,5,7]. Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster. The attachment of the labrum to the bony edge of the glenoid was observed under light microscopy at each position and classified into two . Provides insertion for stabilizing structures, as a fibrous crossroad, with the labrum and. Unable to process the form. Orthopedic physical assessment (6th ed.). The glenohumeral joint is innervated by the subscapular nerve (C5-C6), a branch of the posterior cord of brachial plexus. The sublabral sulcus or recess present in type II and III BLCs represents the most frequent normal anatomic variant of the superior labrum. It covers the intertubercular sulcus and the long head tendon of the biceps brachii muscle, preventing displacement of the tendon from the sulcus. The coracoglenoid ligament arises from the middle of the coracoid process and inserts posterior to the supraglenoid tubercle, covering the top of the glenoid rim, superior labrum, and long tendon of the biceps. Because of this mobility-stability compromise, the shoulder joint is one of the most frequently injured joints of the body. The blood supply to the glenoid labrum was observed and noted during the dissection of all 140 shoulders. 2023 Flat, cleaved, notched, or absent labrum was also seen. In: Pope, T, Bloem, JL, Beltran, J, Morrison, W and Wilson, D (eds. The anterior capsule is thickened by the three glenohumeral ligaments while the tendons of the rotator cuff muscles spread over the capsule blending with its external surface. 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. ), Normal anatomy, variants and pitfalls on shoulder MRI. 6 ). The subscapularis muscle is located anteriorly and appears on axial sections as an intermediate signal intensity structure coalescing into multiple low signal intensity tendinous portions anteriorly which form one tendon merging with the anterior aspect of the capsule before inserting into the lesser tuberosity [2,3,4,5]. This shoulder function comes at the cost of stability however, as the bony surfaces offer little support. The glenoid labrum is a fibrous ring of tissue that attaches to the rim of the glenoid which is the shallow depression of the scapula or shoulder blade where the ball of the humerus sits. The axillary pouch or recess has a U-shaped appearance on MRA or CTA when the inferior glenohumeral ligament is normal (Figures (Figures1212 and and23)23) [4,6,14,15]. Magnetic resonance arthrography (MRA) is especially useful in the diagnosis of labral and ligamentous pathology.4 In determining the difference between a labral tear and a GAGL lesion, imaging can be difficult to interpret, leaving arthroscopy as the definitive diagnostic tool. As mentioned above, the coracoglenoid ligament belongs to the anterior limb of the superior glenohumeral ligament complex and is recently described as a third ligament in the rotator interval [16]. At the superior aspect of the glenoid, the long head of the biceps attaches to the supraglenoid tubercle [4,6]. Congruency is increased somewhat by the presence of a glenoid labrum, a fibrocartilaginous ring that attaches to the margins of the fossa. Diagnosis of glenoid labral tears: a comparison between magnetic resonance imaging and clinical examinations. It extends to the lesser tubercle of humerus. In their retrospective review of patients found tohave anteroinferior labroligamentous injury at arthroscopy, the investigators reported that ADIR was superior to ABER and neutral position in the discrimination between subtypes of Bankart injuries. Shoulder Injury: MRI Pitfalls In: Peh, WC (ed.). Mohammed, H, Skalski, MR, Patel, DB, et al. The two last posterior glenoid rim variants can be associated with varying degrees of posterior shoulder instability due to loss of concavity of the inferior glenoid margin. The labrum is described like a clock face with 12 o'clock being at the top ( superior ), 3 o'clock at the front ( anterior ), 6 o'clock at the bottom ( inferior) and 9 o'clock at the back ( posterior ). The tendon of the short head of the biceps muscle is anterior to the humeral head. It is composed of two separate bundles, the trapezoid and conoid ligaments. The glenoid labrum - Smith - 2010 - Wiley Online Library The shape and slope of the acromion is best seen on sagittal oblique sections. The glenoid labrum provides attachments for the shoulder capsule and various tendons and ligaments, which contributes to shoulder stability by increasing the glenoid surface. Under normal circumstances this bursa does not communicate with the joint space and is not seen on MRI unless it is distended by fluid. It is associated with a focal thinning of the overlying cartilage. 2016;36(6):1628-47. External rotation of the humerus moves the greater tubercle out from under the acromial arch, allowing uninhibited arm abduction to occur.
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