Identify the inferior belly of the omohyoid muscle. The omohyoid muscle is flattened and strap-like. It consists of a superior belly and an inferior belly. The two bellies of this muscle are connected by an intermuscular tendon, that is held by connective tissue to the anterior surface of the internal jugular vein to prevent the vein from collapsing under negative pressure. The position of the inferior belly of the omohyoid muscle divides the posterior triangle into an upper occipital triangle and a lower subclavian (or supraclavicular) triangle.
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