Ultrasonographic Findings for the Suprascapular Nerve: Identifying the Optimal Site for Nerve Conduction Study

doi:2019.21.2.54

J Electrodiagn Neuromuscul Dis > Volume 21(2); 2019 > Article

Original Article

J Korean Assoc EMG Electrodiagn Med 2019;21(2):54-60.
DOI: https://doi.org/10.18214/jkaem.2019.21.2.54 Published online December 31, 2019.

Ultrasonographic Findings for the Suprascapular Nerve: Identifying the Optimal Site for Nerve Conduction Study

Received: 9 April 2019 • Revised: 20 July 2019 • Accepted: 29 July 2019

Abstract

Objective: It is difficult to obtain reliable electrodiagnostic results by stimulating the suprascapular nerve (SSN) at Erb’s point. We used ultrasound to determine the best location to evoke compound muscle action potentials (CMAPs) during electrical stimulation of the SSN. Method: We observed the anatomic location of the SSN using ultrasonography (USG) and its relationship to the surrounding structures. Also, we compared the electrodiagnostic results for the SSN between the conventional nerve conduction study (NCS) technique and USG-guided NCS. Results: The CMAP amplitude of the SSN in the USG-guided technique was significantly larger than that in the conventional technique (p < 0.05). The intensity of current stimulation was also significantly lower in the USG-guided technique than in the conventional technique (p < 0.05). The optimal site for electrical stimulation was a point 7.5 cm lateral from the sternal end (a point 43.0% of the total length of the clavicle from the sternal head of the clavicle) and 2.28 cm above and perpendicular to that point. Conclusion: This study identified the location of the SSN in the supraclavicular region and provides an optimal site for stimulation of the SSN. USG-guided NCS could help to reduce patient discomfort and increase test accuracy.

Key Words: nerve conduction study, suprascapular nerve, ultrasound