Radial Nerve Lesion
Upper LimbOverview
Radial nerve lesion is a peripheral nerve injury affecting motor and sensory function of the dorsal forearm, wrist extensors, and dorsal hand. It commonly results from compression, trauma, or ischemia at various anatomical sites including the axilla, spiral groove of the humerus, or proximal forearm. Clinical presentation varies depending on the level and severity of nerve involvement, ranging from localized sensory loss to profound motor weakness affecting wrist and finger extension.
Pathophysiology
The radial nerve arises from the posterior cord of the brachial plexus (C5-T1) and supplies motor innervation to the triceps, anconeus, wrist extensors (ECRB, ECRL, ECU), finger extensors, and abductor pollicis longus. Compression or injury disrupts axonal conduction, leading to muscle denervation, weakness, and sensory loss in the dorsal first web space and dorsal hand. Depending on lesion location (high vs. low), triceps involvement varies, and recovery depends on nerve regeneration rates and collateral reinnervation.
Patient Education
Understanding your nerve injury level and expected recovery timeline helps guide realistic rehabilitation goals; most nerve injuries show measurable improvement within 3-6 months with consistent therapy, though complete recovery may take 12-18 months.
Typical Presentation
Site
Dorsal forearm, dorsal hand, dorsal first web space; wrist and finger extension weakness; may involve triceps and posterior upper arm depending on lesion level
Quality
Burning or aching pain in dorsal forearm; numbness or tingling in dorsal hand and thumb web space; weakness sensation rather than sharp pain
Intensity
Mild to severe depending on lesion location and severity; pain often 3-6/10, weakness may be complete (0/5) or partial
Aggravating
Resisted wrist extension, finger extension, thumb abduction; gripping activities; pressure over nerve sites (axilla, spiral groove); repeated pronation-supination
Relieving
Rest, immobilization in neutral position, anti-inflammatory measures, nerve gliding exercises, postural adjustments
Associated
Wrist drop (inability to extend wrist), finger drop, thumb abduction weakness, loss of sensation in dorsal web space, triceps weakness if high lesion, absence of wrist extension reflex
Orthopaedic Tests
Wrist Extension Test (Motor)
Procedure
Patient extends the wrist against resistance while the examiner palpates the extensor carpi radialis longus and brevis tendons on the dorsal forearm. Compare bilateral strength using a 0–5 manual muscle test scale.
Positive Finding
Weakness or loss of wrist extension (grade ≤3/5), particularly in radial deviation
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Radial nerve supplies wrist extensors (ECRB, ECRL); weakness suggests radial nerve palsy, typically at or above mid-forearm level
Finger Extension Test (Motor)
Procedure
Patient actively extends all fingers at the metacarpophalangeal joints against resistance. The examiner resists extension and assesses strength symmetrically.
Positive Finding
Weakness or inability to extend fingers at the MCP joint (grade ≤3/5), particularly digits 2–5
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Radial nerve innervates extensor digitorum communis; loss indicates radial nerve involvement distal to posterior interosseous nerve branch
Thumb Extension Test (Motor)
Procedure
Patient extends the thumb at the interphalangeal joint against examiner resistance. Assess strength and compare to the contralateral side.
Positive Finding
Weakness or loss of thumb IP extension (grade ≤3/5)
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Tests extensor pollicis longus, innervated by the posterior interosseous nerve (terminal radial nerve branch); sensitive indicator of distal radial nerve palsy
Radial Nerve Sensory Testing
Procedure
Using two-point discrimination or light touch, test sensation over the dorsal first web space (between thumb and index finger) and dorsal radial forearm. Compare bilaterally.
Positive Finding
Diminished or absent sensation in the radial nerve distribution (dorsal thumb and index finger web space, dorsal radial forearm)
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Tests pure sensory function of the radial nerve; sensory loss in this distribution strongly suggests radial nerve lesion, though sensory deficits may be less prominent than motor deficits
Supination Test (Motor)
Procedure
Patient supinates the forearm against examiner resistance with the elbow flexed to 90°. Assess strength and compare bilaterally.
Positive Finding
Weakness in supination (grade ≤3/5), particularly if radial nerve lesion occurs proximal to the posterior interosseous nerve
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Radial nerve innervates the supinator muscle; weakness suggests proximal radial nerve lesion (e.g., spiral groove or axilla). Distal lesions spare supination via PIN
Tinel's Sign at Radial Nerve Sites
Procedure
Percuss gently along the expected course of the radial nerve (spiral groove, antecubital fossa, dorsal forearm). A positive sign is reproduction of tingling/radiating symptoms distally.
Positive Finding
Tingling or paresthesia in radial nerve distribution (dorsal hand, thumb, index finger) upon percussion
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Suggests nerve regeneration or irritation at the percussion site; may indicate level of lesion. Absence does not exclude nerve injury. Used to monitor recovery in chronic radial nerve palsy.
⚠ Red Flags
- •Signs of spinal cord injury or cervical myelopathy
- •Progressive neurological deficit despite conservative care
- •Severe traumatic injury with complete limb dysfunction
- •Evidence of vascular compromise (pale, cold hand, absent pulses)
- •Signs of complex regional pain syndrome development
- •Uncontrolled pain or worsening despite appropriate management
- •Suspected malignancy or systemic disease causing nerve compression
⚡ Yellow Flags
- •High anxiety regarding permanent disability or nerve damage
- •Catastrophizing about loss of hand function
- •Excessive focus on pain rather than functional recovery
- •Poor adherence to rehabilitation program
- •Secondary gain behaviors or symptom magnification
- •Work-related stress or ergonomic frustration
- •Previous anxiety or depression affecting coping mechanisms
Osteopathic Techniques
Region
Cervical spine and brachial plexus
Technique
Soft Tissue
Rationale
Reduces myofascial restrictions and scalene muscle tension that may compromise brachial plexus neural mobility; improves blood flow to nerve roots
Region
Posterior shoulder and axilla
Technique
Soft Tissue
Rationale
Releases axillary sheath and surrounding tissue restrictions to improve nerve gliding and reduce proximal compression of radial nerve; enhances circulation
Region
Spiral groove of humerus and posterior forearm
Technique
Soft Tissue
Rationale
Directly addresses radial nerve pathway and reduces muscular guarding; improves mobility of nerve through its most common compression site
Region
Wrist and hand extensors
Technique
MET
Rationale
Gentle muscle energy techniques improve muscle-nerve unit mobility without fatiguing denervated muscles; enhances proprioceptive feedback and encourages motor recruitment
Region
Cervical and thoracic spine
Technique
Articulation
Rationale
Improves spinal mechanics and reduces neural tension throughout cervical-thoracic pathway; restores normal segmental mobility that may facilitate nerve recovery
Region
Forearm and wrist
Technique
Functional
Rationale
Maintains optimal wrist and finger position through gravity-reduced patterns; facilitates motor learning in weak muscles through coordinated functional movement patterns
Add-On Approaches
Chinese Medicine
Acupuncture along radial nerve pathway and motor points of wrist extensors; moxibustion to warm and invigorate qi; herbal support for nerve regeneration (ginseng, angelica, astragalus)
Chiropractic
Upper cervical and thoracic spine manipulation to optimize neural foramen patency; assessment of cervical radiculopathy contributing to radial nerve dysfunction
Physiotherapy
Progressive resistance exercises for wrist and finger extensors; functional electrical stimulation to maintain muscle tone during denervation; mirror therapy for neuroplastic recovery; task-specific training for hand function
Remedial Massage
Deep tissue massage to posterior shoulder and forearm; cross-friction techniques to reduce scarring; gentle stripping massage of denervated muscles to maintain tissue quality and circulation
Rehabilitation Exercises
Passive Wrist Extension Mobilization
Gravity-Reduced Finger Extension in Supination
Nerve Gliding Sequence (Radial Nerve Mobilization)
Pronator Stretch in Cervical Neutral
Active Assisted Wrist Extension
Finger Extensor Strengthening with Rubber Band Resistance
Thumb Abductor Strengthening (Abductor Pollicis Longus)
Progressive Wrist Extension Against Resistance
Scapular Stability and Posture Retraining
Cervical Posture and Neutral Spine Awareness
Proprioceptive Retraining - Hand Sensation Activities
Functional Graded Grasp and Release Activities
Referral Criteria
- •Complete radial nerve palsy with no sign of recovery after 8-12 weeks
- •Severe traumatic injury with suspected nerve transection requiring surgical consultation
- •Progressive neurological deficit despite conservative management
- •Development of complex regional pain syndrome features
- •Concurrent cervical spine pathology affecting brachial plexus
- •Signs of vascular compromise requiring vascular surgery assessment
- •Psychological distress or maladaptive pain behaviors requiring mental health support
- •Need for electrodiagnostic studies (EMG/NCS) to confirm diagnosis and lesion location
- •Consideration of surgical exploration or nerve repair if appropriate timeline and imaging findings support intervention