There are two rhomboid muscles - Rhomboid Major and Rhomboid Minor. Rhomboid major is larger and positioned below rhomboid minor. Chins and dips are excellent activities for developing these muscles.
Origin-Spinous processes of C7-T5.
Insertion- Medial border of the scapula, below the level of the spine of the scapula.
Actions- Scapula retraction (bringing the shoulder blades together), Rotation of the scapula downwards
Innervation- Dorsal scapular nerve.