Plexus A feature of all spinal nerves except T1-T12 is that their ventral rami branch and join one another lateral to the column, forming complicated nerve plexuses. Such networks serve the limbs. Only the ventral rami form plexuses. Each muscle in a limb receives its nerve supply from more than one spinal nerve, an advantage in that damage to one spinal segment or root cannot completely paralyze any limb muscle. Cervical Plexus Buried deep in the neck. Supply the muscles of the shoulder and neck. Its single most important nerve is the phrenic nerve, which supplies both motor and sensory innervation to the diaphragm. The primary danger of a broken neck is that the phrenic nerve may be severed. Irritation of the phrenic nerve causes spasms of the diaphragm, or hiccups. Severing of the phrenic nerve and/or C3-C5 results in paralysis of the diaphragm. Brachial Plexus Located partly in the neck and partly in the axilla. Provides virtually all the nerves that innervate the upper limb. Five nerves are especially important:
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This note was uploaded on 11/22/2011 for the course BSC BSC1085 taught by Professor Sharonsimpson during the Fall '10 term at Broward College.