MR Imaging of the Upper Limb: Pitfalls, Tricks, and Tips Federico Bruno, MD a , Francesco Arrigoni, MD a , Raffaele Natella, MD b , Nicola Maggialetti, MD c , Silvia Pradella, MD d , Marcello Zappia, MD c , Alfonso Reginelli, MD b , Alessandra Splendiani, MD a , Ernesto Di Cesare, MD a , Giuseppe Guglielmi, MD e , Vittorio Miele, MD d , Andrea Giovagnoni, MD f , Luca Brunese, MD c , Carlo Masciocchi, MD a , Antonio Barile, MD a, * INTRODUCTION MR imaging, together with ultrasound, is one of the most widely used imaging tools both in the diag- nostic and interventional musculoskeletal fields, suitable for different conditions affecting both the upper and lower limb. 1–20 This imaging technique carries an excellent diagnostic accuracy thanks to its high intrinsic spatial and contrast resolution; however, there are different kinds of anatomic var- iants and artifacts that can be confused with path- ologic entities. 21,22 This article reviews the main conditions that can lead to diagnostic pitfalls in the imaging of the upper limb (mainly the shoulder, elbow, and wrist joints), together with possible tips to solve these equivocal cases. SHOULDER Labrum The glenoid labrum, besides different types of lesions, can present several anatomic variants in morphology, shape, and thickness (triangular being the most common, but frequently round, cleaved, thinned, until the cases of aplasia) that can be a source of diagnostic errors mimicking a tear, especially when encountered posteriorly, where they are less frequent. 23 However, the supraequatorial labrum (between 11 and 3 o’clock) is the area with the greatest anatomic variation, espe- cially involving the biceps labral complex (BLC). 24,25 Disclosure Statement: The authors have nothing to disclose. a Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, via Vetoio 1, L’Aquila 67100, Italy; b Department of Precision Medicine, University of Campania "Luigi Vanvitelli," via Pansini 5, Napoli 80131, Italy; c Department Life and Health "V. Tiberio," University of Molise, Via Francesco De Sanctis 1, Campobasso 86100, Italy; d Department of Radiology, Careggi University Hospital, Largo Brambilla 3, Flor- ence 50134, Italy; e Department of Radiology, University of Foggia, Viale Luigi Pinto 1, Foggia 71100, Italy; f Department of Radiology, Ospedali Riuniti, Universita` Politecnica delle Marche, via Conca 71, Ancona 60121, Italy * Corresponding author. E-mail address: antonio.barile@cc.univaq.it KEYWORDS  MR imaging  Shoulder  Elbow  Wrist  Artifacts  Pitfalls KEY POINTS  MR imaging is one of the most widely used imaging tools to assess several pathologic conditions in the upper limb, especially around the shoulder, elbow, and wrist joint.  Several anatomic variants and imaging artifacts can show unusual appearance and mimic patho- logic entities.  Knowledge of the possible imaging pitfalls encountered in MR imaging of the upper limb, and the available tips and tricks to recognize them, is essential to avoid significant diagnostic errors. Radiol Clin N Am - (2019) -–- https://doi.org/10.1016/j.rcl.2019.03.010 0033-8389/19/Ó 2019 Elsevier Inc. All rights reserved. radiologic.theclinics.com