Abstract

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First, myofascial pain syndrome is an entity with a specific symptomatology for each muscle. Possible trigger-point localizations and referred pain patterns have been described in the literature.3,4 For treatment, there is a separate positioning, palpation technique and penetration angle of the needle to apply to each muscle. The referred pain pattern of the pectoralis major muscle is on the anterior side of the shoulder from the clavicle region to the chest wall and sternal region (Fig. 1A). 3 The referred pain pattern of the pectoralis minor muscle is in the pectoral region, the anterior part of the shoulder region, and the 4th and 5th fingers from the ulnar side along the arm (Fig. 1B). 4

Intervention for the myofascial trigger points of these muscles can be applied in 3 steps:
Step 1. Positioning the patient—The patient is positioned supine with the arm slightly abducted. The physician is positioned on the side of the patient's pathology (not shown). Step 2. Positioning the ultrasound probe—The ultrasound probe (transducer) is placed horizontally at the inferomedial to the axillar region, parallel to the long axis of the muscles (Fig. 1C). Step 3. Needle penetration—The needle is introduced from the lateral to the medial areas though an in-plane approach and inserted at a 45° angle from the lateral area to the medial area (Fig. 1D). First, the pectoralis major muscle, which is on the surface, is reached, and then the pectoralis minor muscle is reached by “steepening” the angle of the needle slightly. Meanwhile, it is important to pay attention to the thoracoacromial artery, which is located between the 2 muscles.
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