
In the three trunks, the superior trunk arises from the union of
the C5 - C6 root. The middle trunk is formed by the C7 root. The
inferior trunk is formed by the C8 - T1 root. Each trunk continues to
divide into two: the anterior and posterior division. After that, six
dividions connect together and form three cords. The lateral cord is
formed from connection of two anterior divisions from the superior
trunk and the middle trunk. The medial cord is an anterior division of
the inferior trunk and the posterior cord is composed of three
posterior divisions. The three cords give rise to major nerves which
control sensation and movement of upper extremity, are
musculocutaneous nerve, radial nerve, median nerve and ulnar nerve.
The benefit of supraclavicular brachial plexus block is to
anesthetize whole upper extremity. Thus, it should be considered
"spinal block for upper extremity", and indicated for arm, elbow,
forearm and hand surgeries. Because almost the brachial plexus
merges into a mass, blocking this position can do anesthesia for all
branches and rapid onset time of sensory block due to small nerves
and minimum local anesthetic.
Supraclavicular brachial plexus block may have some
complications such as about 0.04 - 1% pneumothorax, subclavicular
artery puncture, Claude Bernard Horner syndrome, phrenic nerve
block rarely.
1.4 Using drug in brachial plexus block of our study
Bupivacaine which is local anesthetic, is exerted to block
recoverable conduction of nerve impulse, through mechanism to
inhibit depolarization of neural membrane by preventing of Na+ to
pass this membrane. Bupivacaine inhibits stronger sensory fibers
than motor fibers, because motor fibers have myelin sheath and