Branching patterns of the arterial branches supplying the middle vascular pedicle of the sternocleidomastoid muscle: a topographic anatomical study with surgical applications for the use of pedicles osteomuscular flaps

When making a sternocleidomastoid (SCM) osteomuscular flap to include the clavicle and determining the rotation arc of the osteomuscular flap, it is very important to know the location and the origin of the superior thyroid artery and the distribution pattern of the SCM branch. Accordingly, in this study, the 50 SCM muscles and their arteries were dissected in 26 Korean cadavers, and the results were analyzed. The average distances from the origin of the superior thyroid artery to the clavicular and sternal heads of the SCM muscle were 87.6 mm (57.7-123.8 mm) and 131.2 mm (99.7-166.8 mm), respectively. The average distance from the origin of the superior thyroid artery to the SCM branch entering the SCM muscle was 30.1 mm (16.0-37.7 mm). After entering the SCM muscle, the SCM branches of the superior thyroid artery bifurcated into the clavicular and sternal branches at a point located an average of 58.8 mm (28.4-130.4 mm) above the clavicle. The distribution patterns of the superior thyroid artery were classified into six types based on the branching order and the dual supplies to the SCM muscle. Among them, type I in which the laryngeal branch first divided from the superior thyroid artery was the most common case (36%).