Rhomboid Major

backMusculus rhomboideus major

The rhomboid major is the larger of the two rhomboids, running from the mid spine down to the lower half of the shoulder blade's inner edge. It pulls the shoulder blade in toward the spine.

Rhomboid Major highlighted on an anatomical figure, from behind.
Where it sits, from behind.

Rhomboid major is the lower and by some way the larger of the pair. It runs from four vertebrae in the upper-middle back diagonally down and outward, attaching along the lower half of the shoulder blade's inner edge — a broad, flat sheet of muscle lying under the trapezius.

Because it attaches so far down the shoulder blade, it has more leverage to tilt it than rhomboid minor does. When it shortens, the shoulder blade comes toward the spine and the bottom corner swings inward, which turns the shoulder socket to face slightly downward.

It also has a quiet postural job. It is one of the muscles holding the inner edge of the shoulder blade flat against the ribcage, working with the serratus anterior on the far side of the bone — the two pulling in opposite directions to keep it pinned in place.

Training notes

There is no exercise that trains rhomboid major without also training rhomboid minor and the middle trapezius, and nothing is lost by that. Rowing trains all three, and the useful variable is not which one you are targeting but whether the movement finishes with the shoulder blades actually drawn together.

Rows with the elbows away from the body — a wide-grip seated cable row, a chest-supported row with the upper arms at about forty-five degrees — put more of the work through the rhomboids than a tucked-elbow row, which shifts the emphasis toward the lat.

Because it lies deep to the trapezius, size gains here are not visible on their own; what they contribute to is the thickness of the upper back between the shoulder blades.

Anatomy

Origin
  • Spinous processes of the second to fifth thoracic vertebrae
Insertion
  • Medial border of the scapula, between the root of the scapular spine and the inferior angle
Actions
  • Retracts the scapula, drawing it toward the spine
  • Rotates the scapula downward, turning the shoulder socket to face lower
  • Holds the medial border of the scapula flat against the ribcage
Innervation
Dorsal scapular nerve (C4–C5)

Exercises

Antagonists

Synergists