Rhomboid Anatomy

Rhomboid Major Muscle

Origin: The spinous processes of T2 to T5
Insertion: Vertebral border of the scapula, from inferior to the scapular spine to the inferior angle
Actions: Retraction of the scapula, downward rotation of the scapula
Innervation: Dorsal scapular nerve (C5)
Blood Supply: Dorsal scapular artery and dorsal branches of the posterior intercostal arteries

Primary Actions of the Rhomboid Major

1. Retraction of the scapula

Agonists:

  • Trapezius (middle part)
  • Rhomboid minor

Antagonists:

  • Serratus anterior
  • Pectoralis minor

Secondary Actions of the Rhomboid Major

2. Downward rotation of the scapula

  Agonists:

  • Levator scapulae
  • Serratus anterior (upper fibers)
  • Rhomboid minor
  • Pectoralis minor
  • Trapezius (middle fibers)

  Antagonists:

  • Trapezius (upper and lower part)
  • Serratus anterior (lower fibers)

Middle part of trapezius is a stabilizer.

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Rhomboid Minor Muscle

Origin: Nuchal ligament and the spinous processes of C7 and T1
Insertion: The vertebral border of the scapula, adjacent to the scapular spine
Actions: Retraction of the scapula, downward rotation of the scapula
Innervation: Dorsal scapular nerve (C5)
Blood Supply: Dorsal scapular artery and dorsal branches of the posterior intercostal arteries

Primary Actions of the Rhomboid Minor

1. Retraction of the scapula

Agonists:

  • Trapezius (middle part)
  • Rhomboid major

Antagonists:

  • Serratus anterior
  • Pectoralis minor

2. Downward rotation of the scapula

  Agonists:

  • Levator scapulae
  • Serratus anterior (upper fibers)
  • Rhomboid major
  • Pectoralis minor
  • Trapezius (middle fibers)

  Antagonists:

  • Trapezius (upper and lower part)
  • Serratus anterior (lower fibers)

Middle part of trapezius is a stabilizer.