Rhomboid major

Musculus rhomboideus major

MuscularDeep musclesThoraxLeft and right

View left in 3D View right in 3D

What it is
Parallelogram-shaped sheet deep to trapezius, from the spinous processes of T2–T5 running down and laterally to the medial border of the scapula between the root of the spine and the inferior angle.
Function
Retracts (braces back) the scapula, rotates the glenoid downwards and holds the scapula against the chest wall.
Size
About 10 cm long, 5–6 cm wide, a few mm thick.
Clinical note
Weakness (dorsal scapular nerve injury) lets the medial border of the scapula drift away from the ribs.

Nearby muscular structures Aortic hiatus (median arcuate ligament), Caval opening of the diaphragm, Infraspinatus, Oesophageal hiatus, Rhomboid minor, Serratus anterior, Subscapularis, Supraspinatus, Teres major, Teres minor