The rhomboid minor is a small, cylindrical muscle directly above the rhomboid major, connecting the lower cervical and upper thoracic spine to the medial scapula at the root of the scapular spine. Its actions are identical to the rhomboid major and the two muscles are usually assessed and treated as a functional unit. The dorsal scapular nerve supplies both rhomboids and the levator scapulae, so entrapment of this nerve between the middle scalene fibres can simultaneously affect all three muscles.
| Origin | Nuchal ligament and spinous processes of C7 and T1 |
|---|---|
| Insertion | Medial scapular border at the root of the scapular spine |
| Nerve Supply | Dorsal scapular nerve (C4, C5) |
| Blood Supply | Dorsal scapular artery |
| Actions | Retraction of the scapula; Downward rotation of the glenoid; Elevation of the medial scapular border |
|---|
Acting with the rhomboid major, it draws the superior medial scapular border toward the spine and stabilises the scapula during loaded arm movements, particularly during eccentric pulling activities.
Rhomboid minor involvement is clinically indistinguishable from rhomboid major pathology and the two respond to the same rehabilitation approach. The dorsal scapular nerve can be compressed between the middle scalene muscle fibres, producing a diffuse periscapular pain and weakness pattern that is often confused with a cervical radiculopathy until nerve conduction studies localise the problem.
The rhomboid minor is palpable as a distinct cord at the superior medial scapula just inferior to the trapezius when the shoulder blade is retracted against light resistance, lying immediately above the larger rhomboid major belly.
Acute fibre tears at the superior medial scapula from a sudden forceful arm movement, producing sharp pain that worsens with reaching across the midline and scapular retraction against resistance.
