Location of Brachial Plexus Terminal Branches Determined by Ultrasound and Cadaver


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T he utilization of ultrasound studies to identify the musculocutaneous and axillary nerve could provide great
benefits to Doctors of Osteopathic Medicine as it will expand their ability to efficiently locate and treat in a
clinical setting. There is significant interest in new techniques to properly diagnose and treat injuries,
impingements, and neuropathies, as well as administering local anesthetic nerve blocks, as the brachial plexus
contains large variation in structure from patient to patient. Ultrasound nerve studies provide a pathway to
effectively locate peripheral nerves during a procedure, provide local anesthetic or steroid injections, and
diagnose impingements in the musculocutaneous and axillary nerves. There exists a limited dataset to validate
these methods. This research provides a case study on the efficacy and utilization of ultrasound technology by
the demonstration of how to locate the nerve. A normalized, baseline data of axillary and musculocutaneous
nerve localization techniques, along with minor changes to established techniques, in both cadaveric and
human participants has been explored and provided within this paper. The human population (N = 21)
consisted of eleven males and ten females, ranging from 24-39 years old with a mean age of 26 and was
supplemented with a cadaveric donor population (N=24) consisting of thirteen females and eleven males.
Participants filled out a questionnaire and their whole arm length measurement was obtained prior to ultrasound
imaging. Cadaveric measurements were taken based on the distance of the nerves from different clinically
relevant bony landmarks. The case study obtained significant results with positive correlations between the
different variables both in the cadaveric study as well as the ultrasound portion. A significant positive correlation
p< .05 between the coracoid process to where musculocutaneous nerve pierces coracobrachialis and the
length between coracobrachialis and medial epicondyle was found in males ( rp= 0.58, p=.006). A positive
correlation in females was found to be nonsignificant (rp=0.12, p=.628). 21% of variance in the distance
between the coracobrachialis and where musculocutaneous nerve pierces coracobrachialis is due to the
distance between medial epicondyle and coracoid process (p=.003). A one-unit increase of the distance
between medial epicondyle and coracoid process will increase the distance of coracoid process to
musculocutaneous nerve pierces coracobrachialis by 0.40 units (p=.006). Statistical significance was denoted
by p< .05. The data and techniques outlined in this research aim to provide the foundation for larger clinical
studies in the realm of Osteopathic medicine.