الفهرس 
Anatomical ConsiderationsOnly 14 pages are availabe for public view
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Abstract
Regional anesthesia is of great value for patients with various diseases when general anesthesia may be risky to these patients e.g. hypertension, coronary artery disease, arrhythmia, decompensated heart disease, cerbrovascular accidents, respiratory disease whether acute or chronic, renal and liver impairment.
In order to perform successful paravertebral block, we must understand the physiology of nerve block, anatomy of the intercostal nerves and lumbar plexus together with the pharmacology of local anesthetics used to perform the block.
Local anesthetics are either esters or amides. Ester local anesthetics are broken down by hydrolysis by pseudo cholinesterase enzyme while amide local anesthetics must be metabolized by the liver.
Most widely used local anesthetics are xylocaine and bupivacaine, both are amide local anesthetic.
Local anesthetic act by penetration of the nerve sheath, then permeate the nerve axon membranes and reside there and in the axoplasm. Binding of local anesthetics to sites on voltage gated Na channels prevent opening of the channels by inhibiting the conformational changes that underlie channel activation.