Physiotherapy Management of Musculocutaneous Nerve Injury

Undergraduate Seminar - Detailed Reference Guide for PPT Slides

SLIDE 1 - Introduction & Anatomy Overview

• Coracobrachialis
• Biceps brachii
• Brachialis

Reference: Campbell's Operative Orthopaedics, 15th Ed (2026), p. 3867; Gray's Anatomy for Students, 4th Ed

SLIDE 2 - Aetiology & Classification of Injury

• Penetrating injuries (knife/glass wounds to the axilla) - most common
• Anterior shoulder dislocation
• Fractures of the humeral neck
• Compression injuries (e.g., heavy backpack/rucksack)
• Iatrogenic: surgical damage during anterior approach to humerus or shoulder
• Strenuous exercise causing nerve entrapment in coracobrachialis

Reference: Bradley and Daroff's Neurology in Clinical Practice; Campbell's Operative Orthopaedics 15th Ed

SLIDE 3 - Clinical Features / Assessment

• Weakness/paralysis of elbow flexion
• Weakness of forearm supination (biceps role)
• Weakness of shoulder flexion (coracobrachialis)

• EMG/NCS - helps classify injury and monitor reinnervation
• MRI - exclude structural causes, nerve continuity
• Ultrasound - dynamic assessment

Reference: Campbell's Operative Orthopaedics 15th Ed (2026), p. 3867; Localization in Clinical Neurology 8th Ed; Adams and Victor's Principles of Neurology 12th Ed

SLIDE 4 - Physiotherapy Assessment

1. Subjective history - mechanism, timing, pain character, occupation, functional limitations
2. Manual muscle testing (MMT) - Oxford/MRC scale 0-5 for biceps, brachialis, coracobrachialis
3. Range of motion - active/passive elbow flexion, forearm supination, shoulder flexion
4. Sensory testing - light touch, pinprick, two-point discrimination over lateral forearm
5. Reflex testing - biceps jerk
6. Pain assessment - VAS/NRS, neuropathic pain screening (DN4/PainDETECT)
7. Functional assessment - DASH questionnaire, UEFI
8. Trophic changes - skin quality, temperature, sweating in lateral forearm
9. Electrophysiological correlation - review EMG/NCS reports

SLIDE 5 - Goals of Physiotherapy Management

• Pain control
• Prevention of contractures and joint stiffness
• Prevention of muscle atrophy and disuse weakness
• Maintain ROM of shoulder, elbow, wrist

• Facilitate nerve regeneration
• Re-education of returning motor function
• Sensory re-education
• Functional restoration of elbow flexion and supination
• Return to activities of daily living and occupation

Reference: Physio-pedia: Nerve Injury Rehabilitation; ASHT Evidence and Techniques in Rehabilitation Following Nerve Injuries

SLIDE 6 - Treatment 1: Pain Management

A. TENS (Transcutaneous Electrical Nerve Stimulation)

• High-frequency TENS (80-120 Hz, "conventional TENS") activates large Aβ fibres, activating gate control at dorsal horn
• Low-frequency TENS (1-4 Hz, "acupuncture-like TENS") stimulates endogenous opioid release

• Conventional TENS: 80-100 Hz, pulse width 50-100 µs, comfortable tingling sensation
• Electrodes placed around the painful territory (lateral forearm) or paravertebral at C5-C6

B. Desensitisation Techniques

• Graded tactile stimulation using textures (cotton wool → towel → coarse material)
• Contrast bathing
• Vibration therapy
• Progression from light to heavier stimuli over weeks

C. Manual Therapy & Massage

• Soft tissue massage to the anterior arm/forearm for pain relief and circulation
• Neural mobilisation/neurodynamic techniques: gentle slider/tensioner techniques for the musculocutaneous nerve
• Joint mobilisation: Grade I-II Maitland mobilisations of the glenohumeral and elbow joints for pain modulation

Reference: Physio-pedia: Nerve Injury Rehabilitation; Chu et al., Front Neurol 2025 [PMID: 40260135]

SLIDE 7 - Treatment 2: Splinting and Orthotic Management

• Prevent overstretching of the paralysed biceps/brachialis
• Maintain elbow in slight flexion (70-90°) to reduce gravity-induced elongation of denervated muscle
• Prevent contracture of antagonist muscles (triceps)
• Assist function during the denervation period
• Support the limb weight and reduce shoulder subluxation if needed

Reference: Physio-pedia: Nerve Injury Rehabilitation; ASHT Evidence and Techniques in Rehabilitation Following Nerve Injuries

SLIDE 8 - Treatment 3: Range of Motion and Stretching Exercises

1. Passive ROM exercises (immediately post-injury, daily)
   • Passive elbow flexion-extension, full arc
   • Passive forearm supination-pronation
   • Passive shoulder flexion, abduction, internal/external rotation
   • Frequency: 2-3x daily, 10-15 repetitions each direction
2. Active-assisted ROM (as motor return begins - MRC grade 1-2)
   • Using the unaffected hand to assist
   • Gravity-eliminated positions initially (side-lying for elbow flexion)
3. Active ROM (when MRC grade 3 achieved - can move against gravity)
   • Full active elbow flexion exercises
   • Forearm supination activities
4. Stretching
   • Gentle passive stretching of triceps (elbow flexion stretches)
   • Posterior capsule stretching of shoulder

Reference: ASHT Evidence and Techniques in Rehabilitation Following Nerve Injuries; Physio-pedia: Nerve Injury Rehabilitation

SLIDE 9 - Treatment 4: Neuromuscular Electrical Stimulation (NMES / EMS)

• Denervated muscle undergoes progressive atrophy (fibrotic changes irreversible after 18-24 months)
• NMES aims to maintain muscle bulk and fibre integrity during the long wait for axonal regrowth
• Axonal regeneration rate is ~1-3 mm/day from the site of injury

• Direct electrical stimulation causes muscle fibre contraction, maintaining metabolic activity and preventing protein degradation
• Prevents fibre-type transformation and maintains ACh receptor expression
• Brief low-frequency ES (20 Hz, 1 hour) has been shown to accelerate axonal outgrowth across the repair site

• Waveform: Triangular/exponential pulses (denervated muscle requires longer pulse widths - 100-300 ms)
• Frequency: 1-10 Hz
• Intensity: visible muscle contraction
• Duration: 20-30 minutes per session, once or twice daily
• Electrode placement: directly over the biceps muscle belly (motor point stimulation)

• Standard NMES: rectangular biphasic pulses, 35-50 Hz
• Intensity to produce visible contraction

Reference: Gordon T, J Physiol 2025 [PMID: 39709530]; Chu et al., Front Neurol 2025 [PMID: 40260135]; ASHT Evidence and Techniques in Rehabilitation

SLIDE 10 - Treatment 5: Therapeutic Ultrasound

• Thermal effects: increases tissue extensibility, enhances blood flow, reduces inflammation
• Non-thermal/mechanical (cavitation and acoustic streaming): promotes cell membrane permeability, protein synthesis, and Schwann cell activity
• Promotes axonal sprouting and myelination
• Widely regarded as effective for neural modulation

• Frequency: 1 MHz (deeper tissues, muscle/nerve) or 3 MHz (superficial)
• Mode: Pulsed (20% duty cycle) in acute/sub-acute stages to minimise heating; continuous in chronic stages
• Intensity: 0.5-2.0 W/cm²
• Duration: 5-10 minutes over the affected area
• Application: over coracobrachialis/biceps region, along nerve course

Reference: Chu et al., Front Neurol 2025 [PMID: 40260135]

SLIDE 11 - Treatment 6: Low-Level Laser Therapy (Photobiomodulation)

• Photons at specific wavelengths (630-1000 nm) are absorbed by cytochrome c oxidase in mitochondria
• Increases ATP production, reduces oxidative stress
• Stimulates Schwann cell proliferation and nerve growth factor (NGF) synthesis
• Reduces neuroinflammation
• Accelerates axonal regrowth and myelination

• Wavelength: 630-904 nm (red to near-infrared)
• Power density: 10-50 mW/cm²
• Energy density: 1-4 J/cm²
• Application: along the nerve course and at motor points
• Sessions: 3-5 times/week

Reference: Chu et al., Front Neurol 2025 [PMID: 40260135]

SLIDE 12 - Treatment 7: Strengthening Exercises

Phase 1 - Denervation Period (No voluntary movement, MRC 0-1)

• NMES to maintain muscle bulk
• Passive exercises only
• Mental practice / motor imagery (maintains cortical maps)

Phase 2 - Early Reinnervation (MRC Grade 1-2: trace/flicker of contraction)

• Active-assisted exercises in gravity-eliminated positions
• Pool therapy / hydrotherapy (buoyancy reduces gravity)
• EMG biofeedback to reinforce first returning motor units
• Progressive facilitation: therapist-guided active-assisted elbow flexion

Phase 3 - Mid-Recovery (MRC Grade 3: movement against gravity)

• Active ROM exercises against gravity
• Isometric elbow flexion exercises (progressively increasing hold time)
• Use of resistance bands (Theraband) - lightest resistance initially

Phase 4 - Late Recovery (MRC Grade 4-5: against resistance)

• Progressive resistance exercises (dumbbells, elastic resistance)
• Biceps curls (supinated, neutral, pronated grip - for full brachialis emphasis)
• Hammer curls for brachialis strengthening
• Closed chain exercises (pushing up from chair)
• Sport/occupation-specific training

• Open and closed kinetic chain exercises
• Graded weight progression
• Mirror therapy for cortical re-mapping
• Avoid overloading reinnervating muscles (risk of re-injury)

Reference: Physio-pedia: Nerve Injury Rehabilitation; ASHT Evidence and Techniques in Rehabilitation

SLIDE 13 - Treatment 8: Sensory Re-education

Early Phase (Protective sensation only):

• Threshold detection training (monofilament testing)
• Vibration and temperature awareness exercises
• Protection education: avoid burns, cuts in anaesthetic forearm skin

Late Phase (Discriminative sensation):

• Texture identification (blind texture matching)
• Shape recognition with vision occluded
• Object identification in hand / forearm tapping
• Localisation exercises (identify point of touch with eyes closed)

• Semmes-Weinstein monofilaments
• Two-point discrimination gauge
• Wynn-Parry sensory re-education programme
• Textures: cotton, sandpaper, velcro, leather

Reference: Physio-pedia: Nerve Injury Rehabilitation; ASHT Evidence and Techniques in Rehabilitation

SLIDE 14 - Treatment 9: Aerobic Exercise

• Increases BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) levels
• Enhances blood circulation to nerve tissue
• Improves neuronal function and conduction velocity
• May promote synaptic conduction velocity and neurotrophic support

• Walking, cycling, swimming (aquatic exercise is ideal - gravity-free, improves circulation)
• Moderate intensity: 40-60% VO2max
• 20-40 minutes per session, 3-5 sessions/week
• Incorporate progressive upper limb activity as motor function returns

Reference: Chu et al., Front Neurol 2025 [PMID: 40260135]; Gordon T, J Physiol 2025 [PMID: 39709530]

SLIDE 15 - Treatment 10: Hydrotherapy / Aquatic Therapy

• Buoyancy reduces effective gravity, allowing weak muscles to achieve full ROM
• Hydrostatic pressure reduces oedema
• Warm water increases circulation and reduces muscle spasm
• Resistance of water can be used for progressive strengthening

• Elbow flexion-extension (buoyancy-assisted and buoyancy-resisted progressions)
• Forearm supination
• Shoulder mobilisation

SLIDE 16 - Treatment 11: Biofeedback (EMG Biofeedback)

• Surface EMG electrodes detect returning voluntary motor unit potentials
• Visual or auditory feedback provided to patient
• Helps the patient learn to recruit reinnervating motor units consciously

• Placed over biceps brachii motor point
• Threshold set to encourage even small contractions
• Graded difficulty progression
• Particularly useful in early re-innervation (MRC Grade 1-2)

Reference: Chu et al., Front Neurol 2025 [PMID: 40260135]; Physio-pedia: Nerve Injury Rehabilitation

SLIDE 17 - Treatment 12: Mirror Therapy & Motor Imagery

• Prevents cortical re-mapping/reorganisation during denervation
• Activates mirror neuron system, maintaining motor cortex representation of the affected limb
• Reduces neuropathic pain via cortical remodelling

• Mirror placed at shoulder level; unaffected arm movements are "reflected" to appear as the affected arm
• Perform elbow flexion-extension, supination-pronation
• 15-20 min daily sessions

Reference: Nath P et al., CNS Neurol Disord Drug Targets 2025 [PMID: 39950474]

SLIDE 18 - Post-operative Physiotherapy (After Nerve Repair/Graft)

• Protect the repair: immobilise in the position that eliminates tension (shoulder adducted, elbow flexed)
• Oedema management: elevation, gentle massage
• PROM of uninvolved joints
• NMES to denervated biceps to prevent atrophy

• Progressive ROM
• Gentle NMES
• Scar mobilisation over surgical incision

• Signs of MCN recovery typically appear 4-9 months after repair
• Begin motor re-education, EMG biofeedback
• Sensory re-education as sensory axons mature
• Graded strengthening

Reference: Campbell's Operative Orthopaedics 15th Ed (2026), p. 3868; Current Surgical Therapy 14th Ed

SLIDE 19 - Physiotherapy Outcome Measures

SLIDE 20 - Prognosis

• Isolated MCN injury has better prognosis than most peripheral nerve injuries
• Signs of recovery appear at 4-9 months after repair
• Division of this nerve may cause less disability than any other major nerve, as brachioradialis can partially compensate for elbow flexion
• Excellent results reported after secondary suture or grafting
• Outcomes are better with: earlier repair, younger age, good physiotherapy compliance

Reference: Campbell's Operative Orthopaedics 15th Ed (2026), p. 3868

SLIDE 21 - Consolidated Physiotherapy Management Timeline

REFERENCES FOR PPT SLIDES

1. Campbell's Operative Orthopaedics, 15th Edition (2026) - Chapter 67: Peripheral Nerve Injuries; pp. 3837, 3867-3868. [Primary surgical and clinical reference for MCN anatomy, injury, and treatment]
2. Bradley and Daroff's Neurology in Clinical Practice, 8th Edition - Chapter on Musculocutaneous Nerve; Block 27. [Neurological classification and examination]
3. Adams and Victor's Principles of Neurology, 12th Edition - Musculocutaneous Nerve section. [Clinical neurology reference]
4. Gray's Anatomy for Students (2023) - Brachial plexus and musculocutaneous nerve anatomy. [Anatomical basis]
5. Localization in Clinical Neurology, 8th Edition - Lesions of the Lateral Cord; p. 3612. [Clinical localization and examination]
6. Current Surgical Therapy, 14th Edition - Muscle and Tendon Transfer and Bone and Joint Procedures. [Oberlin procedure and nerve transfer]
7. Chu XL, Zhao XX, Liu SY et al. "Research progress in different physical therapies for treating peripheral nerve injuries." Frontiers in Neurology 2025; 16:1508604. [PMID: 40260135] [Key physiotherapy modalities review - Ultrasound, NMES, LLLT, Aerobic Exercise]
8. Gordon T. "Electrical stimulation of injured nerves promotes recovery in animals and humans." Journal of Physiology 2025. [PMID: 39709530] [Evidence for NMES and ES parameters in nerve repair]
9. Nath P, Roy B, Panigrahi SS. "Recent Trends in Physical Therapy Interventions and Neuromodulation Techniques to Improve Neurorehabilitation." CNS Neurological Disorders Drug Targets 2025. [PMID: 39950474] [Mirror therapy and neuromodulation review]
10. Physiopedia: Nerve Injury Rehabilitation - physio-pedia.com/Nerve_Injury_Rehabilitation [Comprehensive physiotherapy management framework including splinting, TENS, sensory re-education, exercise]
11. ASHT (American Society of Hand Therapists): "Evidence and Techniques in Rehabilitation Following Nerve Injuries" - Comprehensive review of rehabilitation evidence post-nerve repair [Splinting, ES, sensory and motor re-education protocols]
12. Seddon HJ. Classification of peripheral nerve injuries. 3 types: neuropraxia, axonotmesis, neurotmesis. Brain 1943;66:237.
13. Sunderland S. A classification of peripheral nerve injuries producing loss of function. Brain 1951;74:491-516.
14. Wynn-Parry CB. Rehabilitation of the Hand, 4th Edition - Sensory re-education protocols.
15. Miller's Review of Orthopaedics, 9th Edition - Other nerve injuries including musculocutaneous nerve; observation protocols.

The 3 pillars of MCN injury physiotherapy are:

1. Prevent - splinting, PROM, NMES to stop atrophy/contracture
2. Promote - ES, LLLT, ultrasound, exercise to accelerate nerve regeneration
3. Restore - graded strengthening, sensory re-education, functional training