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Questions and Answers
What is the clinical implication of the radial nerve's trajectory shifting from the posterior to the lateral humerus approximately three finger widths above the lateral epicondyle?
What is the clinical implication of the radial nerve's trajectory shifting from the posterior to the lateral humerus approximately three finger widths above the lateral epicondyle?
- It suggests that palpation of the nerve becomes easier due to decreased muscular coverage.
- This anatomical detail is irrelevant as the nerve's function remains consistent throughout its course.
- It indicates a zone of potential entrapment between the brachialis and brachioradialis muscles, increasing susceptibility to compression injuries. (correct)
- It implies a change in the nerve's vascular supply, leading to increased risk of ischemia.
A lesion distal to the elbow will invariably affect both sensory and motor branches of the radial nerve due to their intertwined anatomical course.
A lesion distal to the elbow will invariably affect both sensory and motor branches of the radial nerve due to their intertwined anatomical course.
False (B)
Describe the biomechanical rationale for immobilizing the wrist in extension following radial nerve injury, considering the potential for contracture and the principles of tissue healing.
Describe the biomechanical rationale for immobilizing the wrist in extension following radial nerve injury, considering the potential for contracture and the principles of tissue healing.
Wrist extension immobilization counteracts unopposed wrist flexor contracture while promoting optimal length-tension relationship in healing extensor muscles, minimizing long-term functional deficits.
The superficial sensory branch of the radial nerve innervates the dorsum of digits 1-3, specifically excluding the ______.
The superficial sensory branch of the radial nerve innervates the dorsum of digits 1-3, specifically excluding the ______.
Match each radial nerve pathology with its characteristic clinical presentation:
Match each radial nerve pathology with its characteristic clinical presentation:
In the context of radial nerve injuries, which of the following statements best describes the clinical significance of differentiating between a neuropraxia and an axonotmesis?
In the context of radial nerve injuries, which of the following statements best describes the clinical significance of differentiating between a neuropraxia and an axonotmesis?
Hydrotherapy is universally indicated in the treatment of radial nerve injuries to promote circulation and tissue healing, irrespective of autonomic nervous system involvement.
Hydrotherapy is universally indicated in the treatment of radial nerve injuries to promote circulation and tissue healing, irrespective of autonomic nervous system involvement.
Explain how the position of the elbow (flexion vs. extension) influences the sensitivity of the Upper Limb Tension Test 3 (ULTT3) in detecting radial nerve pathology, considering the nerve's anatomical course and biomechanical principles.
Explain how the position of the elbow (flexion vs. extension) influences the sensitivity of the Upper Limb Tension Test 3 (ULTT3) in detecting radial nerve pathology, considering the nerve's anatomical course and biomechanical principles.
Compression of the radial nerve in the axilla due to prolonged crutch use is clinically referred to as ______.
Compression of the radial nerve in the axilla due to prolonged crutch use is clinically referred to as ______.
Match each muscle innervated by the radial nerve with its primary action:
Match each muscle innervated by the radial nerve with its primary action:
Which of the following best describes the rationale behind using segmental techniques proximal to a radial nerve lesion during treatment?
Which of the following best describes the rationale behind using segmental techniques proximal to a radial nerve lesion during treatment?
In cases of radial nerve injury, promoting a flaccid wrist is crucial during initial management to prevent further nerve compression.
In cases of radial nerve injury, promoting a flaccid wrist is crucial during initial management to prevent further nerve compression.
What are the implications of the superficial sensory branch traveling over the anatomical snuffbox?
What are the implications of the superficial sensory branch traveling over the anatomical snuffbox?
The deep motor branch of the radial nerve, also known as the posterior interosseous nerve, passes through an anatomical structure within the supinator muscle called the ______.
The deep motor branch of the radial nerve, also known as the posterior interosseous nerve, passes through an anatomical structure within the supinator muscle called the ______.
Match each type of radial nerve injury with its corresponding pathological process:
Match each type of radial nerve injury with its corresponding pathological process:
Considering the anatomical origin of the radial nerve, a lesion affecting the C7 nerve root would most likely result in which specific functional deficit?
Considering the anatomical origin of the radial nerve, a lesion affecting the C7 nerve root would most likely result in which specific functional deficit?
Electrical stimulation is universally indicated during the acute phase of radial nerve injury to prevent muscle atrophy, regardless of the degree of nerve damage.
Electrical stimulation is universally indicated during the acute phase of radial nerve injury to prevent muscle atrophy, regardless of the degree of nerve damage.
Explain the rationale behind avoiding traction of a regenerating radial nerve, considering the underlying pathophysiology of nerve regeneration and the potential for adverse outcomes.
Explain the rationale behind avoiding traction of a regenerating radial nerve, considering the underlying pathophysiology of nerve regeneration and the potential for adverse outcomes.
Entrapment of the radial nerve in the radial tunnel primarily affects motor function, resulting in weakness of wrist and finger ______ without sensory deficits.
Entrapment of the radial nerve in the radial tunnel primarily affects motor function, resulting in weakness of wrist and finger ______ without sensory deficits.
Match the signs and symptoms of degeneration with the lesion location.
Match the signs and symptoms of degeneration with the lesion location.
In managing a patient with radial nerve palsy, what is the primary objective of splinting the wrist in extension?
In managing a patient with radial nerve palsy, what is the primary objective of splinting the wrist in extension?
Pronounced muscle atrophy is an early and consistent finding in all cases of radial nerve injury, regardless of the level or severity of the lesion.
Pronounced muscle atrophy is an early and consistent finding in all cases of radial nerve injury, regardless of the level or severity of the lesion.
Describe the pathomechanics of 'Saturday night palsy' and how specific sleeping postures contribute to radial nerve compression.
Describe the pathomechanics of 'Saturday night palsy' and how specific sleeping postures contribute to radial nerve compression.
Superficial radial nerve syndrome, also known as Wartenberg's syndrome, is characterized by paresthesia over the dorsal radial hand and pain over the ______ radial forearm.
Superficial radial nerve syndrome, also known as Wartenberg's syndrome, is characterized by paresthesia over the dorsal radial hand and pain over the ______ radial forearm.
Classify each listed intervention as either 'indicated' or 'contraindicated' in the acute management phase (first few days) of a severe radial nerve axonotmesis, assuming no other complicating factors:
Classify each listed intervention as either 'indicated' or 'contraindicated' in the acute management phase (first few days) of a severe radial nerve axonotmesis, assuming no other complicating factors:
Considering the principles of peripheral nerve regeneration, which treatment strategy is most likely to enhance axonal regrowth following a surgically repaired radial nerve laceration?
Considering the principles of peripheral nerve regeneration, which treatment strategy is most likely to enhance axonal regrowth following a surgically repaired radial nerve laceration?
The presence of a positive Tinel's sign along the course of the radial nerve definitively indicates complete nerve regeneration and return of normal sensory function distal to the point of elicitation.
The presence of a positive Tinel's sign along the course of the radial nerve definitively indicates complete nerve regeneration and return of normal sensory function distal to the point of elicitation.
Explain how altered sensation in radial nerve distribution with anesthesia at the web of the thumb is considered a classic sign of degeneration.
Explain how altered sensation in radial nerve distribution with anesthesia at the web of the thumb is considered a classic sign of degeneration.
Pronator teres syndrome involves compression of the median nerve, while ______ syndrome involves compression of the radial nerve's deep branch as it passes through the supinator muscle.
Pronator teres syndrome involves compression of the median nerve, while ______ syndrome involves compression of the radial nerve's deep branch as it passes through the supinator muscle.
Match each sign/symptoms of degeneration with its corresponding desciption:
Match each sign/symptoms of degeneration with its corresponding desciption:
In a patient presenting with weakness of wrist extension and finger extension, but normal elbow extension, which of the following is the most likely location of the radial nerve lesion?
In a patient presenting with weakness of wrist extension and finger extension, but normal elbow extension, which of the following is the most likely location of the radial nerve lesion?
Heat or cold exposure is appropriate regardless if autonomics are affected
Heat or cold exposure is appropriate regardless if autonomics are affected
A patient presents with wrist drop and numbness on the dorsum of the hand after a humeral fracture. What specific anatomical structure is most likely compromised, and how does this relate to the clinical findings?
A patient presents with wrist drop and numbness on the dorsum of the hand after a humeral fracture. What specific anatomical structure is most likely compromised, and how does this relate to the clinical findings?
After surgical release of the arcade of Frohse to treat PIN syndrome, clinicians advise to avoid heavy lifting or repetitive ______ for several weeks to prevent recurrence.
After surgical release of the arcade of Frohse to treat PIN syndrome, clinicians advise to avoid heavy lifting or repetitive ______ for several weeks to prevent recurrence.
Match the term with its description
Match the term with its description
In the context of sensory re-education following radial nerve repair, which intervention is most effective for improving tactile discrimination after reinnervation has begun?
In the context of sensory re-education following radial nerve repair, which intervention is most effective for improving tactile discrimination after reinnervation has begun?
In patients with radial nerve injuries, 'nerve gliding' exercises should aggressively attempt to reproduce pain to effectively mobilize the nerve and break down adhesions.
In patients with radial nerve injuries, 'nerve gliding' exercises should aggressively attempt to reproduce pain to effectively mobilize the nerve and break down adhesions.
Describe the procedural steps and rationale for performing a modified biceps tendon rupture test as a provocative maneuver for evaluating the radial nerve.
Describe the procedural steps and rationale for performing a modified biceps tendon rupture test as a provocative maneuver for evaluating the radial nerve.
The triangular interval, through which the radial nerve passes, is bordered by the teres major superiorly, the long head of the triceps medially, and the ______ laterally.
The triangular interval, through which the radial nerve passes, is bordered by the teres major superiorly, the long head of the triceps medially, and the ______ laterally.
Associate each electrodiagnostic finding with its corresponding implication for radial nerve injury:
Associate each electrodiagnostic finding with its corresponding implication for radial nerve injury:
Flashcards
Triangular Interval
Triangular Interval
The radial nerve emerges from the triangular interval, bordered by teres major, long head of triceps, and humerus.
Radial Nerve at the Elbow
Radial Nerve at the Elbow
At the elbow, it divides into a deep motor branch and a superficial sensory branch.
Deep Motor Branch (PIN)
Deep Motor Branch (PIN)
The deep motor branch (posterior interosseous nerve) goes through the supinator muscle before innervating the extensor muscles.
Superficial Sensory Branch
Superficial Sensory Branch
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Radial Nerve Origin
Radial Nerve Origin
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Wrist Drop
Wrist Drop
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Radial Nerve Injury Causes
Radial Nerve Injury Causes
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Superficial Radial Nerve Syndrome
Superficial Radial Nerve Syndrome
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Posterior Interosseous Nerve Syndrome
Posterior Interosseous Nerve Syndrome
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Saturday Night Palsy
Saturday Night Palsy
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Radial Nerve Motor Function
Radial Nerve Motor Function
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Study Notes
- The radial nerve is the terminal branch of the posterior cord of the brachial plexus
- It originates from nerve roots C5-C8 and T1
Palpation of the Nerve
- The radial nerve emerges from the triangular interval, also known as the triceps hiatus
- Its borders include the teres major superiorly, the long head of the triceps, and the humerus
- Locate the inferolateral edge of the teres major through palpation and muscle activation to find the triangular interval
- The radial nerve travels underneath the lateral head of the triceps brachii towards the elbow after emerging from the triangular interval
- At the distal posterior humerus, approximately three finger widths above the lateral epicondyle, the radial nerve shifts from the posterior humerus to the lateral humerus
- It wraps anteriorly around the lateral epicondyle, entering the space between the brachialis and brachioradialis muscles
- At the elbow, the radial nerve divides into a deep motor branch and a superficial sensory branch
- The deep motor branch, also known as the posterior interosseous nerve, passes through the supinator muscle, specifically the arcade or canal of Frohse
- It then runs deep down the lateral posterior forearm, innervating the extensor muscles
- The superficial sensory branch continues beneath the brachioradialis and becomes superficial where the brachioradialis muscle turns into a tendon
- It then runs superficially along the lateral radial border towards the wrist
- The superficial sensory branch passes over the anatomical snuffbox
- Distal to the extensor retinaculum, it separates into several small sensory branches that innervate the dorsum of digits 1-3, excluding the fingertips
Palpation of Affected Tissue
- Assess tone and tissue health through the extensors of the upper extremity
- Sensory assessment should include the dorsum of the hand on the radial side
- A radial nerve lesion may manifest as anesthesia on the dorsum of the hand, specifically in the webspace between the pollux and digit 2
Function - Motor
- Triceps
- Anconeus
- Supinator
- Brachioradialis
- ECRL
- ECRB
- ED
- EDM
- ECU
- APL
- EPB
- EPL
- EI
Function - Sensory
- Innervates the dorsum of digits 1-3, not including the fingertips.
- The radial nerve gives off branches that become cutaneous nerves in the upper arm
- These cutaneous nerves are not specifically covered
Pathophysiology - Radial Nerve Injuries
- The radial nerve can be affected by various types of nerve injuries, including:
- Neuropraxia
- Axonotmesis
- Neurotmesis
- Determining the type of treatment depends on the context of the injury
- MOI
- Fractures of the humerus (especially at the spiral groove) or upper 1/3 of the radius, leading to "radial nerve palsy"
- Elbow dislocation
- Prolonged pressure on the lateral arm during surgery
- Compression at the axilla from crutch use (crutch palsy)
- Compression at the axilla or spiral groove of the radius from leaning the arm over the back of a chair or sleeping prone with the arm in full abduction (Saturday night palsy)
- Compression of the nerve by tight forearm muscles or fibrosis (supinator syndrome)
Signs and Symptoms of Degeneration
- A complete lesion results in wrist drop
- If the injury is proximal to the elbow, both sensory and motor branches are affected
- If the injury is distal to the elbow, typically only one branch is affected
- Muscle wasting is possible, depending on the lesion's location
- Possible swelling on the dorsum of the hand, etiology unknown
- Altered sensation in the radial nerve distribution with anesthesia at the web of the thumb
- Classic deformities: wrist drop
Palsy/Lesion
- Radial nerve palsy
- Caused by a lesion, typically due to a fracture
- Location determines whether motor, sensory, or both functions are affected
- Often occurs at the spiral groove of the humerus
- Saturday night palsy
- Caused by compression, often temporary
- Prolonged compression may lead to axonotmesis
- Occurs at the axilla
- PIN Syndrome
- Posterior Interosseous Nerve syndrome, also known as Supinator or Radial tunnel Syndrome
- Entrapment in the arcade/canal of Frohse (supinator)
- Entrapment in radial tunnel: supinator, brachioradialis, ECRL, ECRB
- Symptoms include pain and weakness (motor symptoms only)
- No sensory deficit is present
- Occurs at the supinator
- SRN syndrome
- Superficial Radial Nerve Syndrome, also known as Wartenberg's syndrome
- Causes paresthesia over the dorsal radial hand and pain over the distal radial forearm
- Occurs at the brachioradialis
Radial Nerve Assessment
- Assess for Superficial radial nerve provocation
- Aggravated by ulnar deviation and flexion of the wrist, or percussion over the lateral radial border
- Supinator or Radial tunnel syndrome provocation
- Weakness with supinator MMT or possibly ECRB MMT
- Muscle atrophy
Radial Nerve Treatment
- Context: Treatment for regenerating lesion post-fracture
- Precautions include:
- Avoid traction on the regenerating nerve
- Do not stretch denervated tissue
- Place the arm in a neutral position with pillows to reduce elbow, wrist, and finger flexion
- Use segmental treatment proximal to the lesion, applying techniques perpendicular to the nerve
- Block or stabilize tissue just proximal to the lesion to prevent drag
- Treat flaccid tissue with light stroking and compression
- Distal to the lesion site, treat unaffected tissue with strain toward (but not onto) the flaccid tissue
- Perform PROM to joints in the direction that shortens the affected tissue and nerve
- Goals and approach:
- Promote relaxation
- Decrease edema
- Decrease tone and TrP in muscles proximal to the lesion
- Promote tissue health in denervated tissue through light stroking to shorten the nerve/bunch up tissue or cross-fiber and gentle compressions
- Prevent contracture of unopposed antagonist muscles
- Perform segmental work (distal to the lesion on unaffected muscles/antagonists only)
- Promote joint health with PROM, if possible
- Handle the limb carefully to avoid traction on the nerve
- Encourage returning motor function and use facilitatory ROODS techniques or AAROM with visualization once some function has been regained
- Promote tissue health in reinnervated tissue using Gentle Swedish techniques or sensory stimulation with different textures
- Hydrotherapy:
- Contraindicated if autonomic dysfunction is present, avoiding anywhere on the affected limb, even proximal to the lesion site.
- If autonomics are not affected:
- Use a cool compress over acute injury
- Use modified temperature over affected tissue
- Use mild contrast washes
- Home care:
- If wearing a splint, monitor for pressure sores
- Perform PROM of joints that shortens affected tissue
- Visualize performing actions with the affected limb
- Elevate the limb if edema is present
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