Supine | Head Turned to the Opposite Side | Phrenic Nerve on Anterior Scalene | Thoracic Duct at Risk on the Left
- There is no true internervous plane - this is an intermuscular, interfascial approach and a classic examiner trap.
- The phrenic nerve (C3 to C5) descends on the anterior surface of anterior scalene - identify it first and protect it; it is the key that leads to the trunks.
- The subclavian artery and the plexus trunks lie between the anterior and middle scalene; the subclavian vein lies anterior to anterior scalene, separated from the artery by the muscle.
- On the left side, the thoracic duct arches through the scalene fat pad to the venous angle - injury causes a chyle leak and chylothorax.
- Position supine in the beach-chair, head turned to the opposite side, with the arm prepped free for intra-operative nerve monitoring.
When & Why
What it exposes. The supraclavicular approach is a supine, head-turned exposure through the posterior triangle of the neck that reaches the trunks and divisions of the brachial plexus (C5 to T1), the subclavian artery, and the anterolateral lower cervical and cervicothoracic spine by working between the scalene muscles just above the clavicle. For any lesion proximal to the clavicle, no other single exposure matches this reach. Why supraclavicular. The trunks of the plexus lie most superficially here, sandwiched between the anterior and middle scalene just above and behind the clavicle. A short transverse incision gives simultaneous access to the upper, middle and lower trunks, the divisions, the subclavian artery and the apex of the lung, and it is the anterior route for thoracic outlet decompression.
Transverse incision above the clavicle to reach the trunks and divisions - the workhorse for plexus exploration, neurolysis and cable grafting.
Anterior scalenectomy, cervical rib excision and first rib resection for thoracic outlet syndrome.
A double approach for whole-plexus exposure in complete pan-plexus injuries from roots to cords.
Indications. - Supraclavicular brachial plexus exploration for traction or closed injuries of the upper, middle or lower trunks, divisions and roots C5 to T1
- Nerve grafting and nerve transfer for post-ganglionic ruptures of the trunks (sural, medial antebrachial or other cable grafts)
- Neurolysis or excision of benign plexus tumours (schwannoma, neurofibroma) at the trunk level
- Thoracic outlet syndrome requiring anterior scalenectomy, cervical rib excision, or first rib resection via the anterior route
- Cervical rib producing true neurogenic compression of the lower trunk
- Anterolateral access to the cervicothoracic junction (C7, T1) for selected anterior decompression or biopsy Contraindications. - Active infection of the skin over the supraclavicular fossa
- Medical unfitness for prolonged general anaesthesia or for the beach-chair position
- A lesion clearly confined to the infraclavicular cords or terminal branches (use an infraclavicular or deltopectoral approach instead)
- A predominantly distal peripheral nerve lesion (explore at the site of the lesion) Alternative and combined approaches. - Infraclavicular / deltopectoral approach for the lateral and posterior cords and terminal branches around the coracoid
- Posterior (subscapular) approach for the infraclavicular plexus when anterior scarring is severe
- Transaxillary first rib resection (Roos), an alternative route for TOS decompression that avoids a neck scar
The Exposure
Work from skin to trunks through the posterior triangle, protecting the superficial nerves and vessels, then develop the intermuscular plane along the anterior scalene - using the phrenic nerve as the guide - to open the interscalene gutter and display all three trunks and the subclavian artery.
Exposure sequence
- Supine beach-chair with a small sandbag or roll between the scapulae to drop the shoulder and gently extend the neck - this lifts the plexus toward the surgeon.
- Turn the head 30 to 45 degrees to the opposite side onto a head ring to relax the sternocleidomastoid and open the posterior triangle.
- Prep and drape the ipsilateral arm free into the field for intra-operative nerve monitoring and traction testing.
- Establish somatosensory and motor evoked potentials and triggered EMG and confirm baseline readings before incision.
- A transverse skin-crease (Langer line) incision, about 6 to 8 cm long, placed one to two finger-breadths above and parallel to the clavicle.
- Centred over the posterior border of sternocleidomastoid so the midpoint of the incision lies over the scalene mass.
- The crease incision heals in the natural folds of the neck and is preferred cosmetically; for a combined whole-plexus exposure it can extend laterally over the clavicle toward the deltopectoral groove.
- Incise skin and subcutaneous tissue in the line of the incision, then identify and incise the platysma in the same line.
- Place retractors to expose the investing layer of deep cervical fascia. Platysma is supplied by the cervical branch of the facial nerve and must be repaired at closure.
- The external jugular vein crosses the field obliquely over sternocleidomastoid; it is a reliable superficial guide.
- It can usually be mobilised and retracted, but if it tethers exposure it should be ligated and divided between ligatures.
- The supraclavicular nerves (C3 to C4) from the superficial cervical plexus emerge at Erb's point on the posterior border of sternocleidomastoid and fan out across the clavicle.
- They are sensory. Identify, mobilise gently and retract them rather than sacrifice them, to avoid a numb patch over the clavicle and upper shoulder.
- Incise the investing fascia along the posterior border of sternocleidomastoid and retract the muscle medially, preserving the spinal accessory nerve branch to it.
- The omohyoid (superior belly) crosses the floor; mobilise and retract it, or divide it and mark the ends for later repair.
- The transverse cervical and suprascapular vessels may cross the floor - ligate or coagulate them as needed.
- Mobilise and retract laterally the fatty scalene (posterocervical) fat pad that fills the posterior triangle, exposing the anterior scalene muscle.
- On the left side, take care: the thoracic duct ascends through this fat to reach the venous angle. Use meticulous blunt dissection and low ligation of any suspicious lymphatic channel.
- Find the phrenic nerve (C3 to C5) on the anterior surface of anterior scalene, running from superolateral to inferomedial beneath the prevertebral fascia.
- Gently free it and protect it with a vessel loop. It is the key that leads to the plexus - never divide a vertical structure on anterior scalene without confirming it is not the phrenic nerve.
- Incise the prevertebral fascia along the lateral border of anterior scalene. The trunks come into view in the interscalene gutter.
- Upper trunk (C5 to C6) superiorly, middle trunk (C7) in the middle, and lower trunk (C8 to T1) inferiorly, lying on the first rib close to the subclavian artery.
- The subclavian artery lies with the trunks, posterior to anterior scalene; the subclavian vein lies anterior to anterior scalene, separated from the artery by the muscle.
- Trace and protect the suprascapular nerve from the upper trunk, often visible at the lateral upper trunk.
- On the posterior aspect, be aware of the long thoracic nerve (Bell) penetrating and descending on middle scalene, and the dorsal scapular nerve (C5) piercing middle scalene - injury to Bell's nerve wings the scapula.
The phrenic nerve (C3 to C5) descends on the anterior surface of anterior scalene and is the single most important structure in this approach - it points the surgeon to the trunks and protects the hemidiaphragm. Identify it before any work on the muscle, sling it with a vessel loop, and use bipolar rather than monopolar diathermy in its vicinity. Never divide a vertical structure on anterior scalene until you have confirmed it is not the phrenic nerve.
Examiners frequently ask for the internervous plane of this approach. The correct answer is that there is none - the dissection is intermuscular and interfascial. State this confidently, then explain that the safe deep dissection follows the anterior surface of anterior scalene, using the phrenic nerve as the guide to the trunks. Candidates who invent a plane lose marks for anatomy.
Dangers & Extensions
Structures at risk, by layer
- Structure at risk
- Phrenic nerve (C3 to C5)
- Protection
- Identify first, sling with a vessel loop, bipolar not monopolar diathermy
- Structure at risk
- Thoracic duct (left side only)
- Protection
- Blunt fat-pad dissection, ligate suspicious channels, inspect before closure
- Structure at risk
- Subclavian artery and vein
- Protection
- Proximal and distal control early; vascular injury needs immediate repair
- Structure at risk
- Long thoracic nerve of Bell (C5 to C7)
- Protection
- Avoid deep diathermy on middle scalene during scalenectomy or rib resection
- Structure at risk
- Apical pleura (cupola) and stellate ganglion
- Protection
- Stay off the first rib groove unless resecting; chest radiograph post-operatively
- Structure at risk
- Supraclavicular nerves (C3 to C4) and suprascapular nerve
- Protection
- Mobilise and protect to avoid clavicular numbness and shoulder-girdle motor loss
Complications and their management
- Prevention
- Identify first, vessel loop, avoid monopolar diathermy
- Management
- Observe; most recover; rare diaphragmatic plication if symptomatic
- Prevention
- Proximal and distal control, careful retraction
- Management
- Immediate vascular repair; call vascular surgery early
- Prevention
- Blunt fat-pad dissection, inspect before closure
- Management
- Suture ligation; fat-pad patch; medium-chain diet; re-explore if persistent
- Prevention
- Stay off the cupola of the pleura
- Management
- Chest drain; confirm on post-operative chest radiograph
- Prevention
- Protect the lower trunk and stellate region
- Management
- Usually incomplete and recovers; counsel pre-operatively
- Prevention
- Protect long thoracic nerve on middle scalene
- Management
- Observe and physiotherapy; rare persistent deficit
Extensile options. Extend proximally along the posterior border of sternocleidomastoid toward the mastoid to convert the exposure toward the interscalene region, reaching the C5 and C6 roots and the upper trunk origin. Extend distally over the clavicle to the deltopectoral groove to reach the divisions and the lateral and posterior cords around the coracoid, or add a separate infraclavicular incision (combined double approach) for pan-plexus injuries. For the cervicothoracic spine, retract the carotid sheath medially and work along the longus colli to reach the C7 and T1 vertebral bodies for selected anterolateral decompression, respecting the inferior thyroid artery and recurrent laryngeal nerve medially. Closure and aftercare. Achieve meticulous haemostasis and, on the left, re-inspect the thoracic duct region for any chyle leak. Re-check that the phrenic nerve and all identified trunks and branches are intact, then repair omohyoid if it was divided. Close the platysma meticulously with absorbable suture - this layer is the key to a flat, cosmetic scar and protects against lymphatic collection - and close the skin with a running subcuticular suture. Place a suction drain if a large dead space remains or extensive neurolysis or rib resection was performed. Obtain a chest radiograph in recovery to exclude an apical pneumothorax, and document an upper-limb neurovascular examination against the pre-operative baseline.
Procedures Through This Approach
- Brachial plexus exploration, neurolysis and cable grafting of trunk-level post-ganglionic ruptures, guided by intra-operative nerve action potentials
- Nerve transfers that use supraclavicular donors (for example upper trunk to recipient nerves)
- Excision of plexus tumours (schwannoma, neurofibroma) with a functioning nerve-sparing technique
- Thoracic outlet decompression: anterior scalenectomy, cervical rib excision, division of congenital bands, and first rib resection when indicated
- Anterolateral access to the cervicothoracic junction (C7, T1) for selected anterior decompression, biopsy or stabilisation
Viva & Exam Focus
SCALPSSCALPS - safe sequence from skin to the trunks
DANGERDANGER - the six layered hazards of the supraclavicular fossa
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 24-year-old motorcyclist presents three weeks after a closed right shoulder trauma with weakness of shoulder abduction and external rotation, and preserved hand function consistent with an upper trunk (C5 to C6) lesion. MRI shows a pseudomeningocele at C5 and C6 and a thickened upper trunk. How would you plan and execute a supraclavicular exploration?”
“A 35-year-old woman has slowly progressive thenar wasting and numbness on the ulnar side of the hand with a positive elevated-arm stress test and electrophysiological evidence of a lower trunk lesion. Imaging shows a cervical rib. Discuss the role and execution of supraclavicular surgical decompression.”
“During a left supraclavicular plexus exploration you notice milky fluid welling up from the fat pad near the venous angle. How do you proceed?”
Patient position
- Supine beach-chair with a roll between the scapulae to drop the shoulder
- Head turned 30 to 45 degrees to the opposite side onto a head ring
- Arm prepped and draped free for intra-operative nerve monitoring
- Gentle neck extension lifts the plexus toward the surgeon
- Establish somatosensory, motor evoked potentials and triggered EMG at baseline
Incision and landmarks
- Transverse skin-crease incision 6 to 8 cm, one to two finger-breadths above the clavicle
- Centred over the posterior border of sternocleidomastoid
- External jugular vein crosses SCM obliquely - ligate or retract
- Omohyoid (superior belly) crosses the floor - mobilise, retract or divide
- Scalene fat pad reflected laterally to reveal anterior scalene
Key deep landmarks
- Anterior scalene is the central landmark
- Phrenic nerve (C3 to C5) descends on the anterior surface of anterior scalene
- Trunks lie between anterior and middle scalene - upper C5 to C6, middle C7, lower C8 to T1
- Subclavian artery posterior to anterior scalene with the trunks
- Subclavian vein anterior to anterior scalene, separated by the muscle
Structures at risk
- Phrenic nerve - identify first, sling, protect the hemidiaphragm
- Thoracic duct on the LEFT at the venous angle - chyle leak risk
- Subclavian artery and vein - obtain proximal and distal control early
- Long thoracic nerve (Bell) on middle scalene - winged scapula if injured
- Apical pleura (cupola) - pneumothorax; stellate ganglion - Horner syndrome
Internervous plane
- There is NO true internervous plane
- An intermuscular, interfascial dissection
- Superficially between platysma and SCM, then into posterior triangle fat
- Deep plane developed along anterior scalene using the phrenic nerve as guide
- Prevertebral fascia incised lateral to anterior scalene to expose the trunks
Closure and aftercare
- Re-attach omohyoid if divided
- Meticulous platysmal closure for a flat cosmetic scar
- Suction drain if large dead space or rib resection
- Chest radiograph to exclude apical pneumothorax
- Document and compare upper-limb neurovascular examination with baseline
References
Guidelines, registries and global practice. Management of brachial plexus and thoracic outlet pathology is delivered in specialist units worldwide, and the principles converge across examination systems. The supraclavicular route is the standard exposure for trunk-level plexus lesions and for anterior thoracic outlet decompression, taught in the major hand, nerve and spine atlases (Millesi, Narakas, Kline and Hudson, Mackinnon and Novak). - AO Foundation / orthopaedic nerve surgery consensus - explore closed traction injuries that show no clinical or electrical recovery by three to four months; use intra-operative nerve action potentials to decide neurolysis versus grafting.
- British / European hand and peripheral nerve societies - microsurgical interfascicular cable grafting for post-ganglionic ruptures; nerve transfers for irreparable avulsions; specialised centralised care.
- International thoracic outlet consensus - true neurogenic TOS with objective neurological and imaging findings warrants decompression; the supraclavicular route offers direct visualisation of the compressing structures. Population and clinical evidence. Adult brachial plexus traction injuries are most frequent in young men after motorcycle trauma, with a supraclavicular (upper-trunk-predominant) pattern in roughly half of significant injuries. Cervical ribs are present in a small proportion of the population (commonly quoted at well under 5 percent) and are asymptomatic in the majority; only a minority produce true neurogenic compression. Outcome after grafting and transfer depends on the level of the lesion, the interval to surgery and the specific nerves involved, with shoulder and elbow functions recovering more favourably than hand intrinsics. Global practice variation. In well-resourced centres, microsurgical cable grafting, nerve transfers and intra-operative electrophysiology are standard. In resource-limited settings the same surgical principles are applied with selective grafting and an emphasis on tendon transfers to restore critical function, reflecting both implant and electrophysiology availability. Consent (globally applicable). Discuss phrenic nerve injury and diaphragmatic paralysis, vascular injury to the subclavian vessels, chyle leak and chylothorax on the left side, pneumothorax, Horner syndrome, winged scapula from long thoracic nerve injury, and the long and often incomplete recovery of nerve function.
Transaxillary approach for first rib resection to relieve thoracic outlet syndrome
Introduced first rib resection as a surgical solution for thoracic outlet syndrome by removing the common bony fulcrum compressing the neurovascular bundle, and remains a foundational reference for operative decompression of thoracic outlet compression.
The treatment of brachial plexus injuries
Defined a systematic surgical approach to traumatic adult brachial plexus injuries including the supraclavicular exploration of the trunks, and laid the groundwork for combining nerve grafting and nerve transfers in plexus reconstruction.
Brachial plexus injuries - management and results in 171 cases
Established microsurgical interfascicular cable nerve grafting as the standard for post-ganglionic plexus ruptures, using the supraclavicular corridor to reach trunk-level ruptures and reporting better return of proximal than distal function.
Operative management of selected brachial plexus lesions
Used intra-operative nerve action potentials to distinguish conducting lesions suitable for neurolysis from non-conducting lesions requiring resection and grafting, making electrophysiology central to intra-operative decision-making in plexus surgery.
Thoracic outlet syndrome
Comprehensively reviewed the classification, diagnosis and surgical management of thoracic outlet syndrome and described the supraclavicular decompression including scalenectomy and first rib resection with protection of the phrenic and long thoracic nerves.