Anatomic Basis for Brachial Plexus Block at the Costoclavicular Space A Cadaver Anatomic Study Xavier Sala-Blanch, MD,*† Miguel Angel Reina, MD, PhD,‡§ Pawinee Pangthipampai, MD,|| and Manoj Kumar Karmakar, MD, FRCA, FHKCA, FHKAM|| Background and Objectives: The costoclavicular space (CCS), which is located deep and posterior to the midpoint of the clavicle, may be a better site for infraclavicular brachial plexus block than the traditional lateral paracoracoid site. However, currently, there is paucity of data on the anatomy of the brachial plexus at the CCS. We undertook this cadaver an- atomic study to define the anatomy of the cords of the brachial plexus at the CCS and thereby establish the anatomic basis for ultrasound-guided infraclavicular brachial plexus block at this proximal site. Methods: The anatomy and topography of the cords of the brachial plexus at the CCS was evaluated in 8 unembalmed (cryopreserved), thawed, fresh adult human cadavers using anatomic dissection, and transverse ana- tomic and histological sections, of the CCS. Results: The cords of the brachial plexus were located lateral and parallel to the axillary artery at the CCS. The topography of the cords, relative to the ax- illary artery and to one another, in the transverse (axial) plane was also con- sistent at the CCS. The lateral cord was the most superficial of the 3 cords and it was always anterior to both the medial and posterior cords. The medial cord was directly posterior to the lateral cord but medial to the posterior cord. The posterior cord was the lateral most of the 3 cords at the CCS and it was immediately lateral to the medial cord but posterolateral to the lateral cord. Conclusions: The cords of the brachial plexus are clustered together lat- eral to the axillary artery, and share a consistent relation relative to one an- other and to the axillary artery, at the CCS. (Reg Anesth Pain Med 2016;41: 387–391) U ltrasound-guided (USG) infraclavicular brachial plexus block (ICBPB) is commonly performed at the lateral infraclavicular fossa (LICF) where the cords of the brachial plexus are located deep to the pectoral muscles and surrounding the second part of the axillary artery. 1–3 However, at the LICF, the cords are located at a depth (3–6 cm), 4 separated from one another, 5,6 there is sub- stantial variation in the position of the individual cords relative to the axillary artery (second part), 5,6 and all 3 cords are rarely visualized in a single ultrasound image. 5 This may explain why relatively large volumes of local anesthetic 2 and/or multiple injec- tions 1,2 are used for ICBPB. We have recently proposed 7 that the “costoclavicular space” (CCS), 8 which is located deep and posterior to the midpoint of the clavicle 6 and where the cords of the brachial plexus are relatively superficial in location, 8,9 clus- tered together, 8,9 and share a consistent relation with each other 8,9 may be a more suitable site for USG ICBPB. 7 However, currently, there is paucity of data on the anatomy of the brachial plexus at the CCS. 7–9 Published data describe the topography of the cords below the midpoint of the clavicle, 8,9 in the sagittal plane, 8,9 and in connection with the vertical infraclavicular block technique. 9 There are also no data describing the safety and efficacy of a USG ICBPB at the CCS. We undertook this cadaver anatomic study to define the anatomy and arrangement of the cords of the brachial plexus at the CCS and thereby establish the anatomic basis for USG ICBPB at this proximal site. METHODS This study was approved by the Research Ethics Committee of the University of Barcelona and performed in the dissection room of the Department of Human Anatomy and Embryology at the Medical School of the University of Barcelona. Eight un- embalmed (cryopreserved), thawed, fresh adult human cadavers were studied. None of the cadavers studied had any obvious pa- thology or had undergone any intervention or surgery over the infraclavicular fossa. Anatomic Dissection The cadavers were positioned in the supine position, with the arm abducted to 90 degrees on the side to be dissected. The medial infraclavicular fossa (MICF), immediately caudal to the middle-third of the clavicle and above the medial border of the pectoralis minor muscle, was carefully dissected in layers in 3 ca- davers on both sides (total 6 dissections). The identities of the cords were confirmed independently by the 2 dissectors (X.S.B. and M.K.K.). Thereafter, the pectoralis minor muscle was cut at its lateral edge (ie, from its origin from the coracoid process) and reflected medially to expose the LICF and its contents (Fig. 1A). A single red silicone loop was applied around the axil- lary artery, close to the origin of the thoracoacromial branch, and 2 yellow silicone loops were applied around the cords of the bra- chial plexus (Fig. 1B). The first yellow loop was applied to the cord that was most superficial and adjacent to the axillary artery and the second yellow loop was applied to the other 2 cords that were located slightly deeper and posterior to the above (Fig. 1B). The loops allowed gentle traction to be applied on the cords so that their relationship could be accurately defined. Once the cords were identified, the middle-third of the clavicle was cut and re- moved without disturbing the underlying anatomy of the CCS (Fig. 1C). The arrangement of the cords in the CCS 7 was then de- fined and their relationship to each other and the axillary artery was evaluated and documented photographically (Fig. 1). Anatomic Section Two cadavers with the arms abducted to 90 degrees were frozen at -20 °C for 24 hours. The frozen bodies were placed in From the *Department of Anesthesiology, Hospital Clinic Barcelona; †Depart- ment of Human Anatomy and Embryology, University of Barcelona, Barcelona; ‡Department of Anesthesiology, Madrid-Montepríncipe University Hospital; §School of Medicine, CEU San Pablo University, Madrid, Spain; and ||Depart- ment of Anesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China. Accepted for publication December 16, 2015. Address correspondence to: Manoj Kumar Karmakar, MD, FRCA, FHKCA, FHKAM, Department of Anesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, SAR, China (e‐mail: karmakar@cuhk.edu.hk). The authors declare no conflict of interest. This work was locally funded by the Department of Anesthesiology, University of Barcelona, Barcelona, Spain. Copyright © 2016 by American Society of Regional Anesthesia and Pain Medicine ISSN: 1098-7339 DOI: 10.1097/AAP.0000000000000393 REGIONAL ANESTHESIA AND ACUTE PAIN BRIEF TECHNICAL REPORT Regional Anesthesia and Pain Medicine • Volume 41, Number 3, May-June 2016 387 Copyright © 2016 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited. Protected by copyright. on 27 March 2019 by guest. http://rapm.bmj.com/ Regional Anesthesia & Pain Medicine: first published as 10.1097/AAP.0000000000000393 on 1 May 2016. Downloaded from