The larger of the two rhomboids, this diamond-shaped, superficial back muscle is ribbon-like, arising from the supraspinous ligament, and thoracic vertebrae T2 to T5. Inserting into the scapula’s medial border, it is located deep in the trapezius. On occasion, each of the rhomboids fuse together into one.
The Rhomboid Major provides structure to hold the upper limbs onto the ribcage via the scapula. Inervated by the posterior scapular nerve, its primary functions are elevation of the medial border, stabilization of the scapula against the thoracic wall, and also retraction of the scapula towards the vertebral column.