Korean J Pain.  2019 Oct;32(4):307-312. 10.3344/kjp.2019.32.4.307.

New insights into pathways of the dorsal scapular nerve and artery for selective dorsal scapular nerve blockade

• Cho H
• Kang S
• Won HS
• Yang M
• Kim YD

• KMID: 2462842
• DOI: http://doi.org/10.3344/kjp.2019.32.4.307

Abstract

BACKGROUND
The aim of this study was to clarify the topographical relationships between the dorsal scapular nerve (DSN) and the dorsal scapular artery (DSA) in the interscapular region to identify safe and convenient injection points related to DSN blockade.
METHODS
Thirty shoulders of embalmed Korean cadavers and 50 live subjects were used for dissection and ultrasound (US) analysis.
RESULTS
The running patterns of the DSA and DSN in the interscapular region were classified into 3 types. Type I was defined as nerves that were medial to the artery and parallel without changing location (80.0% of specimens). In type II (13.3%), the nerve and artery traversed one another only one time over their entire length. In type III (6.7%), the nerve and artery traversed one another, resembling a twist. Above the level of the scapular spine, the nerve was always medial to the artery. Below the scapular spine, the number of arteries was obviously decreased. Most of the arteries were lateral to the medial border of the scapula, except at the level of the superior angle of the scapula artery (SA). The positional tendency of the DSN toward the medial or lateral sides from the medial border of the scapula was similar. In US imaging of live subjects, the DSA was most observed at the level of the SA (94.0%).
CONCLUSIONS
Results of this study enhance the current knowledge regarding the pathway of the DSN and DSA and provide helpful information for selective diagnostic nerve blocks in the interscapular region.

Keyword

Arteries; Cadaver; Diagnosis; Dissection; Injections; Nerve Block; Scapula; Ultrasonography

MeSH Terms

Arteries*
Cadaver
Diagnosis
Nerve Block*
Running
Scapula
Shoulder
Spine
Ultrasonography

Figure

• 

  Fig. 1 Marking method for delineating pathways of the dorsal scapular nerve (white pin heads) and dorsal scapular artery (blue pin heads). Ls: levator scapulae, Rmi: rhomboid minor, Rmaj: rhomboid major, Tz: trapezius, S: supraspinatus, SS: spine of scapula, I: infraspinatus.

• 

  Fig. 2 Lines and points defined for analyzing the positional relationship between the dorsal scapular nerve and dorsal scapular artery and medial border of the scapula. Lines A and D indicate the superior angle and the spine of scapula, respectively. Line G indicates the midpoint between the spine of scapula (line D) and the inferior angle of scapula. Lines B, C, E, and F indicate each line divided into three equal parts between the lines A and D, and between the lines D and G, respectively. SA: superior angle of scapula, SS: spine of scapula, IA: inferior angle of scapula.

• 

  Fig. 3 Running patterns of the dorsal scapular nerve (DSN; yellow line) and dorsal scapular artery (DSA; red line) throughout their course of the cadavers. (A) The DSN and DSA run parallel throughout their course. The structures traverse one another only one time (B), or more than 2 times (C). MB: medial border of scapula.

• 

  Fig. 4 Frequency and distance (mm) of the dorsal scapular artery (A) and dorsal scapular nerve (B) from the medial border of scapula at the level of each line of the cadavers. Green and red bars indicate the structures passing toward the medial and lateral sides of the medial border of scapula, respectively.

• 

  Fig. 5 Ultrasound (US) images and frequency of the detected dorsal scapular artery (yellow arrow) in live subjects. Panels A, B, and C depict US images of the same patient at lines A, B, and C, respectively. Tz: trapezius muscle, Rb: rhomboid muscles, SA: superior angle of scapula, R: rib, MB: medial border of scapula.

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