VCOM Louisiana Research Day Program Book 2024

Clinical Research

Cameron Driskell, OMS-III; Savannah Newell, PhD; Patrick Przybylo, OMS-IV; Rebecca Peters, OMS-III VCOM-Louisiana 29 A CONTINUATION OF CADAVERIC EXPLORATION AND ANALYSIS OF VARIATION IN THE INFRACLAVICULAR BRACHIAL PLEXUS

Background: The brachial plexus is a complex system of nerves that provides sensory and motor innervation to the upper extremities as well as parts of the chest and back. [NS1] The plexus begins at the anterior rami of C5- T1. The C5 and C6 roots join to form the superior trunk while the C8 and T1 roots join to form the inferior trunk. The C7 root continues as the middle trunk. [NS2] The trunks then form the three cords. The lateral cord has contributions from the superior and middle trunks, the posterior cord has contributions from all three trunks, and the medial cord is a continuation of the inferior trunk [1]. From the cords arise the five terminal branches. The axillary and radial nerves are the termination of the posterior cord. The musculocutaneous nerve branches from the lateral cord. The ulnar nerve branches from the medial cord. Lastly, the median nerve is formed from contributions from the medial and lateral cords. The clavicle is used as a reference point to separate the plexus into two regions: the supraclavicular part and the infraclavicular part. Studying variations in the brachial plexus is important in improving education, medical practices, and surgical and anesthetic procedures. Objective: The current educational model regarding the brachial plexus includes

rote memorization of the system. Further understanding of common variations could shift the standard to a more dynamic method of learning [NS1] [6]. In addition to improving educational standards, understanding the brachial plexus has significant clinical implications. For example, a brachial plexus blockade[NS2] in place of general anesthetic results in better pain control, less opioid requirements and shorter hospital stays [7]. For a successful blockade, detailed knowledge of anatomy is required. [NS3] Studying variations in the brachial plexus is important in improving education, medical practices, and surgical and anesthetic procedures. When comparing variations by plexus region, the composition of the trunks are unvaried in approximately 84% of studied cases, the divisions for cords regularly in 96% of studied cases, and the terminal branches are formed classically in 75% of studied cases[NS1] [5]. More variations are found within the terminal branches and therefore evaluating the infraclavicular region would be beneficial in understanding the most common variants of the brachial plexus. The objective of this study is to report commonly found variations of the infraclavicular brachial plexus and explore possible clinical implications.

Methods: Cadaveric specimens from the Anatomical Sciences Laboratory at VCOM were utilized in this study. The specimens were provided to VCOM from the University of Texas Southwestern’s Willed Body Program for the consented purpose of education and education based and scientific research. Institutional Review Board (IRB) review was confirmed as not required by the institute’s review board because this study involves cadaveric research. The original dissections of the cadavers were performed by VCOM first-year medical students during the 2023 fall semester. This study focuses on the infraclavicular brachial plexus with the most proximal visible structures identified being the medial, lateral, and posterior cords. These structures were followed until reaching the five main nerve branches - the ulnar, median, musculocutaneous, radial, and axillary nerves. Once all possible structures were identified, each infraclavicular brachial plexus was drawn by hand. The drawings were then converted into digital schematics for analysis of variations. Variations were determined by using Thieme’s Clinical Anatomy, Histology, Embryology, and Neuroanatomy: An Integrated Textbook [8] as a reference for the normal anatomy. The variations were recorded and the frequency of each were calculated.

45 2024 Via Research Recognition Day