Rhomboids

Rhomboid minor

• Origin: the lower part of the ligamentum nuchae and the spinous processes of C7 and T1, with their supraspinous ligaments.
• Insertion: a narrow band, roughly 1 to 2 cm wide, onto the medial border of the scapula at the level of the root (base) of the scapular spine - the smooth triangular area where the spine meets the medial border.
• Frequently fused with rhomboid major; in a minority of people the two are entirely separate with a clear interval, and in others rhomboid minor is doubled.

Rhomboid major

• Origin: the spinous processes of T2 to T5 and the intervening supraspinous ligaments.
• Insertion: the medial border of the scapula from the root of the scapular spine down to the inferior angle, largely through a tendinous arch that attaches firmly at its upper and lower ends with a thinner membranous middle - a detail that matters when you are looking for suture purchase.

Bony landmarks the surgeon uses

• The root of the scapular spine lies at the level of the T3 spinous process with the arm at the side; the inferior angle lies at T7. These two relationships let you site an incision without imaging.
• The medial border is subcutaneous in a thin patient and is the direct route to both muscles.

Fibre direction

Both run inferolaterally from spine to scapula at roughly 45 degrees. That oblique orientation means their pull retracts and elevates the medial border, producing downward rotation of the glenoid.

Dorsal scapular nerve - the only motor supply

• Root value: C5 in approximately 70 per cent of dissected nerves; a C4 contribution is described in a proportion of individuals.
• Origin point: arises from the C5 ventral ramus very proximally, before the roots unite to form the upper trunk. This is the anatomical fact that gives it its diagnostic power.
• Course:
  1. Passes posterolaterally and pierces the middle scalene muscle in the great majority of specimens, roughly at the level of the C5-C6 intervertebral space, together with or just above the long thoracic nerve.
  2. Emerges on the deep surface of levator scapulae, which it supplies in addition to the direct C3 and C4 branches. In a cadaveric series of 23 nerves it reached levator in every specimen, and in about half (48 per cent) it supplied levator alone, never continuing to the rhomboids.
  3. Descends deep to levator scapulae and then deep to the rhomboids, running parallel to and 1 to 2 cm medial to the medial border of the scapula, accompanied by the dorsal scapular artery.
  4. Supplies rhomboid minor first, then rhomboid major through a series of short branches entering the deep surface at intervals along the descent. The motor entry points are therefore spread along the whole medial border rather than concentrated at a single hilum.

It is a purely motor nerve

There is no cutaneous sensory territory. Any complaint of interscapular pain arising from dorsal scapular nerve pathology is deep, aching and non-dermatomal - so a normal sensory examination does not exclude it.

The plexus localisation pearl

Because the dorsal scapular nerve leaves the C5 root proximal to the upper trunk, its state on EMG separates two lesions that look identical clinically:

• Rhomboids denervated - the lesion is at or proximal to the C5 root, raising the possibility of a preganglionic root avulsion, which is not amenable to grafting and requires nerve transfer.
• Rhomboids preserved - the lesion is postganglionic, distal to the take-off, and is potentially graftable.

Combine this with the long thoracic nerve (also very proximal, C5-C7), the phrenic nerve and the cervical paraspinal muscles for a complete proximal screen.

Dorsal scapular artery

• The dominant supply. It arises either as the deep branch of the transverse cervical artery from the thyrocervical trunk (the more common pattern) or directly from the third part of the subclavian artery as a true dorsal scapular artery in a substantial minority of shoulders.
• When it arises directly from the subclavian it passes between the trunks of the brachial plexus, typically between the upper and middle trunks - the reason a dorsal scapular artery can be encountered unexpectedly during supraclavicular plexus exploration.
• It then runs deep to levator scapulae and descends with the nerve on the deep surface of the rhomboids, 1 to 2 cm medial to the medial border of the scapula, anastomosing inferiorly with the circumflex scapular and subscapular systems around the scapular circle.

Why the pedicle position is a surgical fact, not a footnote

• It is the vessel that bleeds briskly and retracts into the paraspinal muscle if divided off the medial border during a Judet approach, a scapulothoracic fusion or a rhomboid harvest.
• It is the pedicle of the lower trapezius island flap and part of the supply of the scapular and parascapular fasciocutaneous flaps, so it must be preserved when those reconstructions are planned.
• It contributes to the scapular anastomosis, the collateral pathway that keeps the arm perfused when the axillary artery is occluded between the thyrocervical trunk and the subscapular artery.

Venous drainage

Venae comitantes accompany the artery and drain into the transverse cervical and subclavian veins.

Superficial

• Trapezius throughout. In the lower part the lateral border of trapezius and the superior border of latissimus dorsi frame the triangle of auscultation, with rhomboid major in its floor.

Deep, moving away from the surgeon

• Dorsal scapular nerve and artery immediately on the deep surface.
• Serratus posterior superior, then the erector spinae medially.
• Ribs and intercostal muscles - and immediately deep to them, the parietal pleura. In a thin patient the pleura is only millimetres beyond the rhomboid layer at the third to fifth intercostal spaces.
• Serratus anterior lies on the costal side of the scapula, forming the gliding surface with the chest wall; the rhomboids and serratus anterior therefore sandwich the medial border between them, and the two scapulothoracic bursae (infraserratus and supraserratus) sit in these planes.

Structures at risk

• Dorsal scapular nerve and artery - the pedicle 1 to 2 cm medial to the border.
• Pleura deep to the ribs during scapulothoracic fusion, deep interscapular injection, or dry needling of the rhomboids - a genuine and reported cause of pneumothorax.
• Spinal accessory nerve on the deep surface of the trapezius, encountered on the way in.

Causes

• Dorsal scapular nerve injury at the middle scalene - traction, direct trauma, or a penetrating injury to the posterior triangle.
• Post-surgical: during a posterior approach to the cervicothoracic spine, first rib resection or scalenectomy for thoracic outlet syndrome, or the medial dissection of a scapulothoracic procedure.
• After an interscalene brachial plexus block - both the dorsal scapular and the long thoracic nerve pierce the middle scalene and can be injured by needle trauma or by local anaesthetic neurotoxicity.
• Neuralgic amyotrophy (Parsonage-Turner syndrome) - typically part of a patchy multi-nerve pattern with severe prodromal pain.
• C5 root pathology - foraminal stenosis, disc herniation, or root avulsion in a traction plexus injury.

Presentation

A dull, deep interscapular ache, worse with sustained postural loading; fatigue and a sense of instability with pulling and overhead activity; and, on careful observation, subtle lateral displacement and medial border lift of the scapula. The patient rarely presents complaining of weakness - they present with pain and a shoulder that feels wrong.

Differential of interscapular pain with a wing

• Trapezius (spinal accessory) palsy - drooped shoulder, weak shrug.
• Serratus (long thoracic) palsy - gross medial winging on the wall push.
• C5 cervical radiculopathy - dermatomal sensory change, weak deltoid.
• Scapulothoracic bursitis or snapping scapula - audible or palpable crepitus.
• Osteochondroma of the ventral scapular surface - a fixed, non-dynamic pseudo-wing.

Dorsal scapular nerve entrapment syndrome

A well-described but under-recognised compression neuropathy at the point where the nerve pierces the middle scalene muscle.

Rhomboid strain and avulsion

• Acute strain is common in rowers, weightlifters (particularly during heavy rows and cleans) and racquet sports. It presents with sharp interscapular pain and localised tenderness and settles with load management.
• Frank avulsion from the medial border is rare and is usually described after a violent eccentric pull. Ultrasound or MRI shows retraction and a fluid-filled gap. Repair through a medial border incision with transosseous sutures or anchors is described for a symptomatic, retracted avulsion in an athlete.

Rhomboid involvement in scapular dyskinesis

Rhomboid over-activity, not weakness, is the more usual finding in the overhead athlete with scapular dyskinesis: the rhomboids and levator dominate over an inhibited serratus anterior and lower trapezius, holding the scapula in downward rotation and anterior tilt and narrowing the subacromial space. Rehabilitation therefore targets serratus and lower trapezius activation with rhomboid and levator down-training, not rhomboid strengthening.

Snapping scapula

The supraserratus and infraserratus bursae lie in the planes around the medial border; inflammation of the infraserratus bursa, between serratus anterior and the chest wall, produces crepitus and pain that can be mistaken for rhomboid pathology. Assess for a superomedial angle prominence and consider CT to look for a bony cause.

Rhomboid involvement in muscular dystrophy

In facioscapulohumeral dystrophy the periscapular muscles including the rhomboids are affected together with the trapezius and serratus, producing gross multidirectional winging and pointing toward scapulothoracic fusion rather than any single tendon transfer.

Indication

Open reduction and internal fixation of displaced scapular body, neck and glenoid fossa fractures, and access to the posterior glenoid.

Position and incision

• Lateral decubitus or prone, with the arm draped free so it can be positioned in flexion and internal rotation to relax the deltoid.
• Boomerang (Judet) incision along the scapular spine laterally to the acromion, turning distally along the medial border to the inferior angle.

The intervals used

1. Superficially: the deltoid is elevated off the scapular spine and reflected laterally, protecting the axillary nerve as it emerges from the quadrangular space, and the trapezius is elevated medially.
2. The medial parascapular interval: the rhomboids and levator scapulae are detached flush with the medial border of the scapula, subperiosteally, leaving a repairable tendinous cuff. This releases the medial tether and allows the infraspinatus and teres minor to be raised as a laterally based flap on their pedicle, giving the classical Judet exposure of the whole dorsal scapula.
3. Modified (minimally invasive) Judet: the muscle flap is not raised. Instead the work is done through two windows - the interval between infraspinatus and teres minor for the lateral border and glenoid neck, and the plane along the medial border deep to the rhomboids for the medial border. This spares the rhomboid detachment entirely and has largely replaced the full Judet in most units.

The rule for the rhomboid detachment

Detach with a knife on bone, hugging the medial border. The dorsal scapular nerve and artery lie 1 to 2 cm medial to your blade. Retract the released muscle medially with a broad retractor placed against the muscle, never with a self-retainer biting into the paraspinal mass.

With distances

Triangle of auscultation

Bounded by the medial scapular border laterally, the lateral border of trapezius medially and the superior border of latissimus dorsi inferiorly, with rhomboid major in the floor. Retracting the scapula laterally, by bringing the arm forward across the chest, widens the triangle and gives direct access to the posterior chest wall at the level of the sixth rib without dividing any muscle - the classical muscle-sparing route for a posterior thoracotomy or a rib biopsy.

Posterior cervicothoracic spinal approaches

Subperiosteal elevation from the spinous processes takes the rhomboid origins along with the trapezius. Stay strictly subperiosteal and avoid lateral excursion beyond about 4 cm from the midline at C7-T1 to protect the dorsal scapular nerve and vessels.

Scapulothoracic fusion

Requires elevation of the rhomboids and trapezius from the medial border, decortication of the ventral scapular surface and the underlying ribs, and passage of cerclage wires or cables around ribs 3 to 7, usually reinforced with a plate along the medial border. Pleural injury is the characteristic complication, and a routine post-operative chest radiograph is mandatory.

Scapulothoracic bursectomy and superomedial angle resection

Performed open through a medial border incision or arthroscopically from medial portals. The rhomboid and levator insertions are released and repaired; over-resection of the superomedial angle risks detaching the levator insertion entirely and destabilising the scapula.

The role of the rhomboids

In the Eden-Lange transfer for irreparable trapezius palsy, the rhomboids provide two of the three limbs:

• Rhomboid minor is detached from the medial border and transferred laterally onto the infraspinatus fossa, substituting for the middle trapezius.
• Rhomboid major is detached and transferred laterally onto the infraspinatus fossa below the minor, substituting for the lower trapezius.
• Levator scapulae, the third limb, goes laterally onto the scapular spine to substitute for the upper trapezius; in the modified transfer it is carried further laterally toward the lateral spine or acromion to lengthen its upward-rotation moment arm.

Technical requirements

• Confirm the dorsal scapular nerve is intact on EMG. All three donors depend on it, and transferring denervated muscle is a wasted operation.
• Detach each muscle with a wafer of bone or a tendinous cuff for suture purchase; the membranous middle of rhomboid major is poor suture tissue.
• Protect the dorsal scapular pedicle - it enters the deep surface medially and must not be tethered or divided as the muscle is swung laterally. Excursion is limited to a few centimetres for this reason.
• Fix through bone tunnels or troughs in the infraspinatus fossa with transosseous sutures, tensioned with the arm at about 30 degrees of abduction.

Outcome expectation

Reliable pain relief with improvement in scapular position and cosmesis; abduction improves but is rarely normalised. Long-term follow-up shows the correction is durable where the trapezius palsy is truly isolated; the reported failures had a coexisting long thoracic and dorsal scapular nerve lesion.

Repairing the medial border after a Judet approach

Restoring the rhomboid and levator insertions is not optional. Leave a tendinous cuff on the muscle, drill transosseous tunnels through the medial border every 1.5 to 2 cm, and repair with heavy non-absorbable suture while the scapula is held retracted. Protect in a sling for 4 to 6 weeks with no active retraction, then begin progressive scapular control work.

Failure of repair

Non-healing of the medial detachment produces a painful, laterally translated scapula with subtle winging - an iatrogenic rhomboid palsy without any nerve injury at all. This is one of the reasons the modified, muscle-sparing Judet has displaced the classical flap.

Rhomboid avulsion repair

For a genuine traumatic avulsion in an athlete, approach through a longitudinal incision over the medial border, identify the retracted muscle, mobilise it gently without dissecting medially into the pedicle, and reattach with suture anchors along the medial border footprint.