Ultrasound-Guided Trigger Point Injection for Myofascial Trigger Points in the Subscapularis and Pectoralis Muscles.

We read with great interest the article by Shin, et al.1 in the May 2014 issue of the Yonsei Medical Journal. The authors described the application of ultrasound-guided (USG) trigger point injection for myofascial trigger points in the subscapularis and pectoralis muscles to post-mastectomy patients. The article was supported by four USG pictures.

We, as anesthesiologists, have been practicing the same procedure for our mastectomy patients. In reviewing the article, we noticed that there is an error in the labeling of the muscles, an ultrasound image of the subscapularis muscle in a transverse plane. The muscles labeled as the teres major (Tmj) and teres minor (Tmi) are in fact the latissimus dorsi and the teres major, respectively.

According to the authors, with transverse placement of the USG probe, depicts the teres minor muscle running along the costal surface of the scapula and touching the subscapularis muscle. This is not feasible, however, in light of the anatomical origin and insertion of these muscles in chapter 46 of Gray's Anatomy.2 In addition the presence of an unlabeled thoracodorsal vessel just below the medical end of the teres major supports our opinion.3

Moreover, if we scan the area in the transverse plane, moving upward from the inferior angle of the scapula, we would be able to visualize continuation of the latissimus dorsi and the origin of the teres major, along with various other relevant structures. Accordingly, we have provided a USG picture with correct labeling that supports our explanation (Fig. 1).

Fig. 1

This shows the transverse probe placement. LD, latissimus dorsi; TM, teres major; Tm, teres minor; SSC, subscapularis; SA, serratous anterior; SC, lateral border of scapula; TV, thoracodorsal vessels.