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16 Cards in this Set
- Front
- Back
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What is epineurium? |
The sheath of a peripheral nerve.
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What is perineurium?
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The connective tissue sheath surrounding each bundle of nerve fibers (fascicle) in a peripheral nerve.
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What is endoneurium?
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The interstitial connective tissue in a peripheral nerve, separating individual nerve fibers. |
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What are the classes of peripheral nerves? |
Class I: Neurapraxia Class II: Axonotmesis Class III:Neurotmesis |
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Explain Neurapraxia
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Local compression or blockage
Impairment in nerve conduction above & below the blockage, across the point of in the nerve Damage- Myelin Strength- ⇩ Sensation- ⇩ MSR- ⇩ Autonomics- Normal Wallerian Degen- No Reversible?- 0-3 mos. |
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List examples of Neurapraxia |
Bell's Palsy( Facial nerve)- Doesn't get sensory/motor (2-8 wks to heal) Saturday night palsy (Radial nerve compression in spiral groove)- Laying on arm for 5-8 hrs Carpal Tunnel Syndrome- (Median Nerve entrapment)- Early Onset Pressure over the peroneal nerve at the fibula head- Cast palsy |
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Explain Axonotmesis
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The neural tube is intact, the axonal damage has occurred with wallerian degeneration distal to the lesion. Damage- Axon Strength-⇩; some muscle atrophy Sensation-⇩ or absent MSRs- ⇩ or absent Autonomics- Variable Wallerian Degen- Yes Reversible ?- 3-16 mos. Regen @ 1-4 mm/day |
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Explain Neurotmesis
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Nerve injury with complete loss of axonal function and disruption of the neural tube (Cut Nerve)
Damage- Transection of nerve fiber & sheaths Strength- Absent; muscle atrophy Sensation- Absent MSRs- Absent Autonomics- Absent Wallerian Degen- Yes Reversible ?- With approximation |
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What is affects recovery speed?
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Dependent on proper orientation of axons as they regenerate. ★ Class II regeneration- occurs at 1-4 mm/day max healing ★ Bell's Palsy- 2-8 wks to heal |
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Explain Polyneuropathy
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Affects multiple nerves and results in sensory changes, distal weakness, and hyporeflexia. May be manifested as axonal damage/demyelinated of axons.
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What is Polyneuropathy related to? |
Diabetes
Alcoholism Renal disease Malignancies Leprosy Guillain-Barres syndrome Metabolic abnormalities Malnutrition Toxic effects of drugs or chemicals |
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What is Wallerian Degeneration? |
Atrophy is muscle loss associated with loss of innervation, therefore the muscle cells cannot regenerate. As muscle cells degenerate they are replaced with functional useless fibrous scar tissue. |
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Cervical Plexus (C1-C4) |
C2- Branch to sternocleidomastoid C3,C4- Branch to Trapezius, Levator Scapulae, Middle Scalenes C4- Branch to ANT Scalenes C3-C5- Phrenic Nerve- comes from cervical plexus & is the sole motor supply for the diaphragm. Shoulder Shrug |
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Brachial Plexus (C5-T1) |
Plexus runs from the neck to the axilla passing b/w the clavicle and the first rib. Cords form the nerves to the arm- the median, ulnar, radial, & musculocutaneous nerve. Injury Thoracic Outlet Syndrome- Severed |
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Lumbosacral Plexus (L1-S5) |
A nerve plexus formed by divisions of the coccygeal & sacral & ulnar nerves. Supplies the lower limbs & perineum & coccygeal area. |
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What is total loss of sensation? |
Complete loss of any single sensation (anesthesia)
The type and extent of impairment are related to the location and size of the vascular lesion. Symptoms of crossed anesthesia (ipsilateral facial impairments with contralateral trunk and limb involvement) typify brainstem lesions. |
