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Rhomboid major muscle

The rhomboid major is a flat, quadrilateral muscle located in the upper back, beneath the trapezius. It plays a crucial role in stabilizing and retracting the scapula, thus assisting in the movement and support of the shoulder girdle. The rhomboid major, along with the rhomboid minor, forms the rhomboid muscles, which are essential for maintaining proper posture and upper limb mechanics.

Synonyms:

  • Musculus rhomboideus major

  • Rhomboideus major muscle

Function:

  • Retracts (adducts) the scapula towards the vertebral column

  • Rotates the scapula to depress the glenoid cavity

  • Fixes the scapula to the thoracic wall

  • Assists in stabilizing the scapula during upper limb movements

Origin:

  • Spinous processes of T2 to T5 thoracic vertebrae

  • Supraspinous ligaments of corresponding vertebrae

Insertion:

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

Nerve Supply:

  • Dorsal scapular nerve (C4, C5), a branch of the brachial plexus

Artery Supply:

  • Dorsal scapular artery (also known as the deep branch of the transverse cervical artery)

Vein Supply:

  • Accompanying veins of the dorsal scapular artery, draining into the subclavian vein

MRI Appearance:

  • T1-weighted: Intermediate to low signal intensity, similar to other skeletal muscles

  • T2-weighted: Intermediate signal intensity; edema or injury appears as high signal

  • STIR (Short Tau Inversion Recovery): High signal intensity in cases of muscle strain, tear, or inflammation; normal muscle is low signal

CT Appearance:

  • Appears as a soft tissue density muscle band deep to the trapezius and superficial to the posterior thoracic wall

MRI images

Rhomboid major muscle MRI image

MRI image

Rhomboid major muscle anatomy MRI axial image -img-00000-00000_00001

CT images

Rhomboid major muscle anatomy MRI axial image -img-00000-00000