Rhomboid major is larger than its functional counterpart, rhomboid minor, which lies superiorly.
On each side, it arises from discrete tendons from the vertebral spines of T2 to T5 and the intervening supraspinous ligaments. It passes obliquely downwards and laterally to insert into the medial (vertebral) border of the scapula. It does so between the triangular area at the base of the spine and the inferior angle.
Rhomboid major lies superficial to the long muscles of the spine. It lies deep to the trapezius muscle except at its inferior border where it lies in the base of the triangle of auscultation.
It is supplied by the dorsal scapular nerve (C5) from its deep surface. Its functions are considered in the submenu.