An anomalous muscle crossing the supraclavicular triangle: the cleidotrachelian muscle.

An abnormal muscle is described that passes superficially across omohyoid in the left posterior triangle of the neck. Its origin resembles that of scalenus anterior, but its form is triangular and it inserts directly onto the superior surface of the clavicle just lateral to the clavicular head of sternocleidomastoid. Its anatomical course gives it morphological and embryological interest; its relations in the supraclavicular triangle give it considerable surgical relevance. The name cleidotrachelian muscle is suggested.