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Home / Hand Soft Tissue / Nerve compression syndromes and brachial neuritis
Hand Soft Tissue

Nerve compression syndromes and brachial neuritis

Median and ulnar nerve compression at elbow and wrist, Guyon canal, and brachial neuritis

29 questions 4 source pages 2 images 1 fact-check flags

Images appear with the first question taken from each source page — tap a question to open it.

29 questions
Q1What are the causes of compression in pronator syndrome?📷▸
Pronator syndrome compression of median nerve at elbow level
Pronator syndrome compression of median nerve at elbow level
  • Supracondylar process
  • Ligament of Struthers
  • Lacertus fibrosus
  • Deep head of pronator teres
  • FDS arch
Q2What is pronator syndrome and how does it present?▸
  • Compression of the median nerve at the elbow level
  • Numbness of the medial 3 and a half fingers
  • Numbness of the thenar region
Q3What are the causes of compression in AIN (anterior interosseous nerve) syndrome?▸
  • Lacertus fibrosus
  • Deep head of pronator teres
  • FDS arch
  • Accessory head of FPL
Q4What is the presentation of AIN syndrome?▸
  • Weakness of FPL
  • Weakness of index and middle FDP
  • Weakness of pronator quadratus
Q5How do you distinguish pronator quadratus from pronator teres weakness?▸
  • PQ: resisted pronation with elbow in full flexion (least mechanical advantage to PT)
  • PT: resisted pronation with elbow slightly flexed
Q6What does the photo show and what is the differential diagnosis?▸
  • Failed abduction of the little finger (unilateral)
  • No claw hand, no interossei muscle wasting
  • DDx: Wartenberg sign, cervical myelopathy (bilateral)
Q7What is Wartenberg's sign?▸
  • Weak interossei
  • Ulnarly deviated pull of EDM + EDC
Q8How do you assess suspected cubital tunnel syndrome?▸
  • Delineate high vs low ulnar nerve palsy
  • R/O other causes with full neuro exam: C8/T1 root (I/F FDP, APB), sensory, myelopathic hand signs, LL involvement
  • High: cubital valgum (malunited lateral condyle fracture), limited elbow range (OA elbow)
  • Check Tinel and elbow flexion test (>60 sec)
  • McGowan grading: 1 sensory, 2 weakness, 3 wasting
Q9List the sites of ulnar nerve compression around the elbow.▸
  • Around the medial intermuscular septum and arcade of Struthers (medial intermuscular septum to medial head of triceps)
  • Medial epicondyle in cubital valgum
  • Epicondylar groove
  • Cubital tunnel: SOL, Osborne ligament (medial epicondyle to olecranon), FCU aponeurosis between the two heads
  • The flexor pronator aponeurosis (fascia btw FDP and FDS), anconeus epitrochlearis
Q10Outline the conservative management of cubital tunnel syndrome.▸
  • Splint with elbow in 30 degrees flexion, wrist in neutral to relax FCU
  • NSAIDs
Q11What are the indications and pros/cons of ulnar nerve decompression in situ?▸
  • CI: subluxable nerve, SOL, scar, severe elbow deformity
  • Adv: minimal dissection, can do under LA, protects the vascular mesoneurium, avoids scarring
  • Disadv: if released more proximal to the epicondylar groove, risk of nerve subluxation and a new site of compression
Q12What are the indications and pros/cons of medial epicondylectomy?▸
  • Releases compression against the epicondyle
  • For visible and symptomatic subluxating nerve, or thin patients where subcutaneous anterior transposition may not be feasible
  • Pros: smaller wound, nerve can seek its own course of least resistance, less ischaemic injury, no need to sacrifice the articular branch
  • No need to immobilize elbow
  • Cons: injury to MCL (prevent by not going too basally, <70%), pain, weakness of flexor origin, too little resection may not fully relieve traction
Q13How do you perform a medial epicondylectomy?▸
  • GA, supine, shoulder abducted and externally rotated; incision centred on medial epicondyle; protect the medial antebrachial nerve
  • Proximally release arcade of Struthers and medial intermuscular septum, then Osborne ligament, distally the FCU aponeurosis and deep flexor pronator aponeurosis
  • Expose the medial epicondyle subperiosteally and remove 3-4mm
  • Reattach periosteum in 'pant over vest' manner to the CFP
  • Identify the ulnar nerve posteriorly in its groove
Q14Compare the types of anterior transposition of the ulnar nerve.▸
  • Subcutaneous: technically easiest; nerve becomes superficial, more dissection of blood supply
  • Submuscular: least recurrence, good protection and vascular bed; needs 3 weeks immobilisation, risk of recompression (improve with Z-plasty), not good in severe OA, too close to joint may cause impingement
  • Intramuscular: nerve buried in a groove within flexor-pronator muscle; risk of recurrence, more bleeding, better preserves nerve blood supply
Q15What is the evidence for in-situ decompression versus transposition?▸
  • Ilyas JHS 2019 meta-analysis: functionally in-situ decompression = transposition; transposition has more complications
  • JAMA Network 2020 (Wade): in-situ decompression associated with lower risk than any form of transposition
  • Addition of epicondylectomy associated with increased probability of symptomatic cure without increasing complication risk
Q16How is an anterior transposition of the ulnar nerve performed?▸
  • GA, supine, shoulder abducted and ER; incision centred on medial epicondyle; avoid the medial antebrachial nerve (pierces brachial fascia adjacent to basilic vein)
  • Anteriorly develop skin flap to expose the CFO; posteriorly identify the ulnar nerve in its groove
  • Proximally release arcade of Struthers and medial intermuscular septum, then Osborne ligament; distally release FCU aponeurosis and deep flexor pronator aponeurosis
  • For submuscular: sharply divide the tendinous origin of the medial epicondyle, retract the flexor mass distally, place nerve deep to the fascial sling
  • Flex and extend the elbow to ensure no kinking; release tourniquet before closure for haemostasis; immobilise elbow 3 weeks
Q17What are the boundaries of Guyon's canal?▸
  • Ulnar: pisiform
  • Radial: hook of hamate
  • Floor: transverse carpal ligament
  • Roof: volar palmar ligament and palmaris brevis
Q18What does Guyon's canal contain?▸
  • Ulnar nerve and ulnar vessels (ulnar NV)
Q19Describe the three zones of Guyon's canal.▸
  • 1. Before bifurcation: contains both motor and sensory
  • 2. Motor, radial
  • 3. Sensory, ulnar
Q20What is the epidemiology of Parsonage-Turner syndrome?📷▸
Brachial Neuritis
Brachial Neuritis
  • Uncommon: 1.6-3 cases per 100,000 persons per year
  • Males, middle-age (4th decade; 20-60 most common, average 41)
  • Usually unilateral; bilateral in 10-30% (16% simultaneously)
Q21What are the causes and risk factors of brachial neuritis?▸
  • Idiopathic (INA) or hereditary (HNA) neuralgic amyotrophy
  • Multifactorial: autoimmune / genetic / infectious / environmental / biomechanical
  • Viral infections 25-55% (EBV, VZV, Coxsackie B, parvovirus B19, CMV, mumps, smallpox, HIV); bacterial (Leptospira, TB, Yersinia, Salmonella, Borrelia)
  • Immunizations 15% (tetanus, hepatitis B); perioperative and peripartum 14%; strenuous exercise 8%
  • Drugs (abacavir, streptokinase, heroin, infliximab, interferon); iatrogenic (interscalene block, surgery, lumbar puncture, irradiation)
Q22Which nerves are most commonly affected in brachial neuritis?▸
  • Any nerve or branch within the brachial plexus; extra-plexus ~17%
  • Most common: long thoracic, suprascapular, axillary, musculocutaneous, radial nerves
  • Other: cervical roots, AIN, PIN, lateral antebrachial cutaneous nerve (LABC)
Q23What is the proposed pathogenesis of idiopathic neuralgic amyotrophy?▸
  • Autoimmune: increased blastogenic activity of lymphocytes and increased complement-fixing antibodies to peripheral nerve myelin
  • Biomechanical: mobility of the upper trunk predisposes to wear-and-tear on the blood-nerve barrier
  • Multifactorial: autoimmune / genetic / infectious / environmental / biomechanical
Q24Describe the three phases of brachial neuritis.▸
  • Phase I: sudden severe shoulder pain (90%), radiates to proximal arm/neck; lasts days to weeks
  • Phase II: painless flaccid paralysis - 24 hours (33%) to 4 weeks (80%); patchy paresis is highly characteristic
  • Phase III: slow recovery of motor function over 6-18 months; duration proportional to duration of pain phase
Q25What are the physical examination features of brachial neuritis?▸
  • Signs of denervation: fasciculations and atrophy
  • Pain not affected by motion or palpation
  • Severe weakness of shoulder, especially external rotation and abduction
  • LMN signs: hypotonia and areflexia; medial scapular winging
  • Sensory change in 78%; autonomic dysregulation in 15%
Q26What investigations are used in brachial neuritis?▸
  • Bloods: CBC and ESR usually normal, elevated liver enzymes; positive antiganglioside antibodies and ANA
  • MRI: early T2 diffuse signal hyperintensity (edema) in affected muscles; late T1 fatty infiltration and atrophy
  • EMG: early PSW/fibrillation; late (3-4 months) chronic denervation and early reinnervation with polyphasic MUAPs
  • NCS: reduced amplitude with preserved conduction velocity and distal latency (less useful than EMG)
  • CSF: usually normal, mildly elevated protein, slight pleocytosis and oligoclonal bands
Q27What is the differential diagnosis of brachial neuritis?▸
  • Cervical spine radiculopathy
  • Rotator cuff pathology
  • Entrapment neuropathy
  • Idiopathic hypertrophic brachial neuritis (IHBN): painless upper limb weakness with brachial plexus hypertrophy
Q28What is the treatment and prognosis of brachial neuritis?▸
  • Nonoperative: observation and pain control (NSAIDs/physio); oral corticosteroids may hasten pain resolution but do not affect progression or prognosis
  • Operative if no regeneration or early recovery by 6-9 months on exam and EMG: neurolysis, neurorrhaphy, grafting, nerve or tendon transfers
  • Recurrence rare in non-hereditary cases; poor prognosis: female, lower trunk, persistent pain and no motor recovery by 3 months, hereditary cases; age has no effect
  • Recovery: 66% show motor recovery within 1 month; excellent in 36% at 1 year, 75% at 2 years, 89% at 3 years; may take up to 8 years
Q29What is the operative outcome in brachial neuritis?▸
  • Exploration of patients without neurologic recovery reveals hourglass-like constrictions in peripheral nerves with no external compression
  • Neurolysis alone was superior to neurorrhaphy and nerve grafting

Fact check

66% have recovery of motor function within 1 month in Parsonage-Turner syndrome — misleading/unsupported — secondary sources cite 66% early partial or any recovery at 1 month; validated functional recovery is 36% at 1 year, 75% at 2 years and 89% at 3 years — (medium confidence) — source
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