CorpusHuman Anatomy
MuscularMuscle

Rhomboid major

Musculus rhomboideus major

Also known as: rhomboids, rhomboideus major

A flat, quadrilateral muscle from the T2–T5 spinous processes to the medial border of the scapula below the spine. It retracts the scapula and rotates it downward.

Show on body map Muscles — Posterior View

Overview

Rhomboid major lies deep to trapezius. Its parallel fibres run inferolaterally from the spinous processes of T2–T5 (and supraspinous ligaments) to the medial border of the scapula, from the root of the spine down to the inferior angle. Rhomboid minor lies just above it, and the two often fuse.

The rhomboids retract the scapula, pulling it toward the spine, as when squeezing the shoulder blades together or rowing. With levator scapulae they rotate it downward. Most importantly, they fix the scapula against the thoracic wall so that the arm muscles have a stable base to work from. They also act as antagonists of serratus anterior. Both rhomboids are supplied by the dorsal scapular nerve (C4–C5), which runs with the deep branch of the transverse cervical (dorsal scapular) artery along the medial border of the scapula.

Anatomy

Origin

Spinous processes of T2–T5 and the supraspinous ligaments.

Insertion

Medial border of the scapula, from the level of the spine to the inferior angle.

Action

Retracts and downwardly rotates the scapula; holds it against the thoracic wall.

Innervation

Dorsal scapular nerve (from the C5 root of the brachial plexus).

Nerve roots

C4–C5

Arterial supply

Dorsal scapular artery (deep branch of the transverse cervical artery); dorsal branches of the upper posterior intercostal arteries.

Relations

Deep to trapezius and superficial to the erector spinae and serratus posterior superior.

Function

  • Retracts the scapula
  • Downwardly rotates the scapula
  • Fixes the scapula to the thoracic wall

Clinical significance

Dorsal scapular nerve palsy

This palsy is rare. It weakens retraction and causes mild lateral winging of the scapula, with the medial border drifting laterally. Entrapment can occur where the nerve pierces the middle scalene.

Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.