Musculus rhomboideus minor
Rhomboid minor muscle is a muscle of the back and upper limb, which acts on the scapula.
- origin: nuchal ligament, spinous processes of C7 and T1 vertebrae
- insertion: medial border of scapula at the root of the spine of scapula
- nerve supply: dorsal scapular nerve (C4, C5)
- arterial supply: dorsal scapular artery
- action: adducts (retracts) and internally rotates the scapula; aids in scapular elevation
The rhomboid minor muscle sits in parallel with and above the rhomboid major muscle. It forms a narrow ribbon of muscle and arises from the vertebral spines of C7 and T1 before inserting into the scapula on its medial border below the attachment of the levator scapulae muscle.
The rhomboids are innervated by the dorsal scapular nerve from the C5 root of the brachial plexus. This nerve passes through the middle scalene, running deep to levator scapulae which it also supplies. It innervates the rhomboids from their deep surface.