On a Variant Muscle Originating from the 2nd and 3rd Ribs and Inserted into the Medial Border of the Scapula Beneath the Anterior Serratus Muscle Anatomical Case Report on Findings in the Course of Dissecting Class, Sapporo Medical College (No. 1)

A variant muscle originating from the 2nd and 3rd ribs and inserted into the medial border of the scapula was observed in a 67 year-old Japanese male cadaver at Sapporo Medical College, 1989. Since it is supplied by a twig of the dorsal scapular nerve, this variation is considered to belong to the rhomboid muscle group. This interpretation is also supported by the result of nerve fiber analysis of the dorsal scapular nerve. This variation seems to offer insights into the differentiating process of the rhomboid muscles from the muscular anlage destined to become the levator scapulae, rhomboid and anterior serratus muscles.departmental bulletin pape