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CC BY 4.0 · J Brachial Plex Peripher Nerve Inj 2025; 20(01): e31-e40
DOI: 10.1055/a-2591-2757
Original Article

Brachial Plexus Anatomy of Sprague Dawley Rat Compared to Human

Alison N. Jacobs
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Luke J. Bolstad
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Natalie Martinson
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Ethan Mickelson
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Matthew R. Ceelen
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Owen R. Lefebvre
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Roy Ram Klein
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
,
Daniel J. Hellenbrand
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
2   Department of Biomedical Engineering, University of Wisconsin Madison, Madison, Wisconsin, United States
,
Amgad S. Hanna 
1   Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, Wisconsin, United States
2   Department of Biomedical Engineering, University of Wisconsin Madison, Madison, Wisconsin, United States
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Abstract

Brachial plexus injury (BPI) occurs when the brachial plexus (BP) is compressed, stretched, or avulsed. A mild BPI results in acute arm pain, tingling, or numbness, while more severe injuries can lead to permanent muscle weakness or loss of function of the extremity if left untreated. Many BPI treatments developed in small animal models fail to translate effectively to human clinical trials. Furthermore, there is a lack of comparative studies exploring the anatomical differences between BPs in different species. The objective of this study is to compare the BP anatomy between humans and Sprague–Dawley (SD) rats to determine if the SD rat is a suitable model for studying BPI mechanisms and treatments. Four human BPs were compared to five SD rat BPs. Gross anatomical analysis revealed mild similarities in the branching patterns of SD rat and human BP. Histological results indicated that SD rats had significantly smaller musculocutaneous (p = 0.0095), median (p < 0.0001), and ulnar (p < 0.0001) nerves compared to humans. Additionally, SD rats had significantly fewer axons than humans in the musculocutaneous (p = 0.0190), median (p < 0.0001), and ulnar nerves (p < 0.0001). Due to the anatomical and histological differences between the two species, therapeutic interventions for BPIs developed in rats should be further tested in a larger animal model, such as the Wisconsin Miniature Swine, before progressing to human clinical trials.

Keywords

anatomy - avulsion - brachial plexus - nerve injury - Sprague Dawley Rat

Authors' Contributions

A.J.: Study concept and design, data acquisition including animal dissections, data analysis and interpretation, drafting of the manuscript, and critical revision. L.B. and N.B.: Data acquisition, data analysis and interpretation, drafting of the manuscript, and critical revision. E.M.: Study concept and design, data acquisition including animal dissections. M.C.: Study concept and design, data acquisition including animal dissections, data analysis and interpretation, drafting of the manuscript, and critical revision. O.L. and O.R.: Data analysis and interpretation, drafting of the manuscript, and critical revision. D.H.: Data analysis and interpretation, statistical analysis, drafting of the manuscript, and critical revision. A.H.: Study concept and design, data acquisition including all animal dissections and human fixed cadaver dissection, data analysis and interpretation, drafting of the manuscript, and critical revision. All authors read and approved the final manuscript.




Publication History

Received: 30 March 2025

Accepted: 17 April 2025

Article published online:
29 May 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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