Rhomboid major muscle
Musculus rhomboideus major
Rhomboid major is a flat, diamond-shaped muscle of the upper back that ties the scapula's medial border to the thoracic spine.
At a glance
- English
- Rhomboid major muscle
- Latin (TA2)
- Musculus rhomboideus major
- System
- Muscle
- Region
- Back
- Side
- Paired, left and right
About the rhomboid major muscle
Rhomboid major is a flat, four-sided sheet in the upper back, lying deep to trapezius and just below rhomboid minor. As its name suggests it is shaped like a rhombus, and it is the bigger of the two rhomboids. It is grouped with the superficial back muscles that connect the upper limb to the trunk, and in some people the two rhomboids are fused into one.
It arises from the spines of T2 to T5 and the supraspinous ligament between them. Its fibres run down and outward to the scapula's medial border, covering the stretch from where the scapular spine begins down to the inferior angle. Beneath it lie serratus posterior superior and the erector spinae, and along its scapular edge run the dorsal scapular nerve and artery.
With rhomboid minor it pulls the scapula towards the spine and keeps it pressed flat against the chest wall, a holding job it shares with serratus anterior and pectoralis minor. It also helps levator scapulae to raise the scapula's medial border, which rotates the glenoid downward. These movements oppose the upward rotation produced by serratus anterior and trapezius, so the rhomboids help to lower the arm against resistance.
Its nerve is the dorsal scapular nerve, mainly from C5, and its blood comes from the dorsal scapular artery. Weakness or injury lets the scapula drift away from the spine and wing slightly when the arm is pushed forward, with pain and reduced shoulder movement. Strengthening the muscle is a routine part of rehabilitation for shoulder problems.
Attachments, action and supply
- Origin
- Spines of T2 to T5 and the supraspinous ligament between them.
- Insertion
- Medial border of scapula, from opposite the scapular spine down to the inferior angle.
- Action
- Retracts the scapula, holds it against the chest wall and rotates the glenoid downward.
- Nerve supply
- Dorsal scapular nerve (C4, C5).
- Blood supply
- Dorsal scapular artery, with dorsal branches of the upper posterior intercostal arteries.
Anthromica
See the rhomboid major muscle where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
