Rhomboid Minor: Origin, Insertion, Nerve & Scapular Stability

The Rhomboid Minor is a small, cylindrical muscle of the upper back. It sits immediately superior to the Rhomboid Major and inferior to the Levator Scapulae. While often fused with the Major, the Minor acts as a specific anchor for the root of the scapular spine.

[Image of Rhomboid Major muscle anatomy]

Quick Anatomy Snapshot

Origin (Proximal)	Lower part of the Nuchal Ligament and Spinous Processes of C7 and T1.
Insertion (Distal)	Medial border of the Scapula at the Root of the Spine of the Scapula.
Nerve Supply	Dorsal Scapular Nerve (C5).
Blood Supply	Dorsal Scapular Artery (Deep branch of Transverse Cervical Artery).
Primary Actions	Retraction: Adducts the scapula toward the spine. Elevation: Lifts the medial border of the scapula. Downward Rotation: Rotates the glenoid cavity downwards.

Deep Dive: The Cervical Connection

While the Rhomboid Major connects the Thoracic spine to the scapula, the Rhomboid Minor connects the Cervical spine (Neck) to the scapula.

1. The Anatomical Sandwich

The Rhomboid Minor is located in the intermediate layer of the back muscles.
• Superficial to it: The Trapezius muscle.
• Deep to it: The Serratus Posterior Superior and the Erector Spinae (Splenius Capitis/Cervicis).
This layering is important when treating trigger points; you must palpate through the Trapezius to reach the Rhomboid Minor.

2. The Root Anchor

Its insertion point is very specific: the triangular smooth area at the medial end of the Spine of the Scapula. This provides a pivot point for scapular rotation.

Physio Corner: Clinical Relevance

💪 Functional Fact: Because the Rhomboid Minor originates from the C7/T1 vertebrae and the Nuchal Ligament, tension in this muscle often contributes to the "hump" seen at the base of the neck in patients with Forward Head Posture (Dowager's Hump).

Palpation

1. Locate the Spine of the Scapula.
2. Follow the spine medially until you reach the vertebral border (Root of the Spine).
3. The cord-like muscle running obliquely upward from this point to the base of the neck (C7) is the Rhomboid Minor.
4. Ask the patient to lift their hand off their lower back ("Chicken Wing") to engage the muscle.

⚠️ Clinical Pathology: Scapular Dyskinesis
Weakness in the Rhomboids (Major and Minor) allows the scapula to drift laterally and upwardly rotate excessively, often leading to shoulder impingement. Conversely, tightness here contributes to the "Downward Rotation Syndrome," causing neck pain.

Manual Muscle Testing (MMT)

The Rhomboid Minor is tested simultaneously with the Rhomboid Major.

Testing Tip: To differentiate from the Middle Trapezius (pure retraction), focus on the downward rotation component. Having the patient place their hand behind their back biases the Rhomboids.

Step-by-Step Procedure (Oxford Scale)

Grade	Patient Action & Resistance
Grade 3, 4, 5 (Against Gravity)	Position: Prone (face down). Arm internally rotated, hand resting on lumbar spine (palm up). Action: Patient lifts the hand away from the back. Resistance: Applied against the medial border of the scapula, pushing outward (into abduction). Grade 3: Clears hand from back. Grade 4/5: Holds against resistance.
Grade 2 (Gravity Eliminated)	Position: Sitting. Arm at side. Action: Patient squeezes shoulder blades together and slightly down. Result: Scapula moves toward the spine.
Grade 0, 1 (Palpation)	Action: Palpate at the root of the scapular spine. Cue: "Squeeze your shoulders back." Grade 1: Contraction felt. Grade 0: No activity.

Frequently Asked Questions

Is Rhomboid Minor superficial or deep to Rhomboid Major?

Neither. They are on the same plane. Rhomboid Minor is Superior to Rhomboid Major. They lie edge-to-edge, often appearing as one continuous sheet.

Does it attach to the skull?

No. It attaches to the Nuchal Ligament and the spinous processes of C7 and T1. It does not reach the occiput.

What is the antagonist?

The primary antagonist is the Serratus Anterior, which protracts and upwardly rotates the scapula.

Test Your Knowledge: Rhomboid Minor Quiz

1. Where does Rhomboid Minor originate?

2. Where does Rhomboid Minor insert?

3. Which nerve supplies Rhomboid Minor?

4. What is the primary action of the Rhomboids?

5. The Rhomboid Minor lies deep to which muscle?

6. Which ligament provides an origin point for Rhomboid Minor?

7. What type of rotation does Rhomboid Minor assist with?

8. Rhomboid Minor sits immediately superior to:

9. A patient with weak Rhomboids will likely present with:

10. True or False: Rhomboid Minor inserts along the entire medial border of the scapula.

References

• Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2018). Clinically Oriented Anatomy. 8th ed. Philadelphia: Wolters Kluwer.
• Standring, S. (2016). Gray's Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier.
• Kendall, F. P. (2005). Muscles: Testing and Function, with Posture and Pain. 5th ed. Lippincott Williams & Wilkins.