Podcast
Questions and Answers
What is a better outcome when nerve injury is localized to the endoneurial tube?
What is a better outcome when nerve injury is localized to the endoneurial tube?
Which nerve injuries can result in a characteristic medial rotation and extension of the forearm?
Which nerve injuries can result in a characteristic medial rotation and extension of the forearm?
Which of the following conditions is NOT a direct cause of nerve injury?
Which of the following conditions is NOT a direct cause of nerve injury?
Which symptom is commonly associated with nerve injuries leading to weakness?
Which symptom is commonly associated with nerve injuries leading to weakness?
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What common nerve injuries may occur in the upper limb due to birth trauma?
What common nerve injuries may occur in the upper limb due to birth trauma?
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Which type of nerve injury is characterized by a complete loss of motor, sensory, and autonomic function?
Which type of nerve injury is characterized by a complete loss of motor, sensory, and autonomic function?
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What is the typical recovery time for motor function in a neuropraxia injury?
What is the typical recovery time for motor function in a neuropraxia injury?
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In axonotmesis, what remains intact despite the loss of axon and myelin sheath?
In axonotmesis, what remains intact despite the loss of axon and myelin sheath?
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What type of nerve injury could be caused by a blunt blow to the nerve?
What type of nerve injury could be caused by a blunt blow to the nerve?
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How does the rate of axonal growth in axonotmesis compare to other nerve injuries?
How does the rate of axonal growth in axonotmesis compare to other nerve injuries?
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What is a common physical position associated with biceps damage in Erb's Palsy?
What is a common physical position associated with biceps damage in Erb's Palsy?
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Which nerves are involved in Klumpke’s Paralysis?
Which nerves are involved in Klumpke’s Paralysis?
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Which characteristic occurs as a result of Ulnar nerve injury at the wrist joint?
Which characteristic occurs as a result of Ulnar nerve injury at the wrist joint?
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What is the primary motor function affected by a radial nerve injury?
What is the primary motor function affected by a radial nerve injury?
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Which of the following is NOT a predisposing factor for Carpal Tunnel syndrome?
Which of the following is NOT a predisposing factor for Carpal Tunnel syndrome?
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What is a common symptom of Carpal Tunnel syndrome?
What is a common symptom of Carpal Tunnel syndrome?
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What treatment is commonly used for Carpal Tunnel syndrome?
What treatment is commonly used for Carpal Tunnel syndrome?
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How does Klumpke’s Paralysis primarily affect hand function?
How does Klumpke’s Paralysis primarily affect hand function?
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Study Notes
Nerve Injuries in the Upper Limb
- The presentation focuses on investigating nerve injuries in the upper limb within the musculoskeletal system.
- Topics include nerve anatomy and histology, types of nerve injuries, causes of nerve injuries, diagnosis of nerve injuries, and specific examples of upper limb nerve injuries.
Nerve Anatomy and Histology
- A nerve is composed of bundles of axons (nerve fibers) along with connective tissues: epineurium (outer layer), perineurium (wraps fascicles), and endoneurium (surrounds individual axons).
- Axons can be myelinated or unmyelinated. Myelinated axons have a myelin sheath, with Nodes of Ranvier.
- Blood vessels run alongside the nerve.
Nerve Injury Types
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Neuropraxia: Transient interruption in nerve conduction. Temporary loss of function that reverses within hours to months. Caused by compression, blunt blows or shock injuries. Motor function often affected more than sensory.
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Axonotmesis: Severe crush or contusion. Loss of axon continuity, but the epineurial and endoneurial tubules remain intact. Equal loss of motor and sensory components. Axon regrowth happens at a rate of 1-3 mm per day.
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Neurotmesis: Severe contusion, stretch or laceration. Complete loss of motor, sensory, and autonomic function. Continuity of the nerve's connective tissue is lost. Outcome is more favorable if only the endoneurial tube is damaged.
Causes of Nerve Injuries
- Mechanical: Compression, traction, laceration.
- Others: Metabolic, ischemia, thermal, radiation.
Diagnosis of Nerve Injuries
- History: Patient's account of the injury.
- Clinical examination: Assessment for weakness, wasting (muscle loss), flaccidity, loss of sensation (pain/temperature/fine touch), and loss of sweating.
Examples of Nerve Injuries in the Upper Limb
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Erb's Palsy: Nerve injury affecting shoulder, arm, and hand movement in infants. Often caused by shoulder dystocia, causing traction injury to the brachial plexus (C5-6). Involved nerves include suprascapular, musculocutaneous, and axillary. Characteristics include arm hanging by side, rotated medially, forearm extended and pronated. Biceps damage is called 'waiter's tip'. Treatments involve nerve transplants, subscapularis releases, and latissimus dorsi tendon transfers.
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Klumpke's Paralysis: Paralysis affecting forearm and hand muscles. Results from brachial plexus injury that affects the C8 and T1 nerves. Affects intrinsic muscles of the hand and wrist/finger flexors (flexor digitorum profundus ulnar half).
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Claw Hand: Occurs due to ulnar nerve laceration at the wrist joint. Loss of intrinsic hand muscles (interossei) leading to difficulties with abduction/adduction of fingers. Medial two lumbrical paralysis greatly reduces little and ring finger movement. Characterised by a hand deformity called "ulnar claw".
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Wrist Drop: A sign of radial nerve injury. Usually caused by humerus dislocations or fractures. Paralysis of triceps and posterior compartment muscles. Inability to extend the elbow, wrist, and fingers. Loss of sensation over the radial nerve's cutaneous innervation.
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Carpal Tunnel Syndrome: Median nerve entrapment which causes numbness, pain, or paresthesia (pins and needles) in the thumb, index, long, ring, or part of the little fingers. Risk factors include: diabetes, obesity, pregnancy, hypothyroidism, and heavy manual work involving vibrating tools. Conservative treatments include night splints and corticosteroid injections.
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Description
This quiz explores nerve injuries in the upper limb, focusing on anatomy, types of injuries, their causes, diagnosis, and examples. Learn about the histological structure of nerves and the implications of different injury types such as neuropraxia and axonotmesis.
