·378·PARTVINERVOUSSYSTEMof the trunks is divided into an anterior and a posteriorclavicle in company with the axillary artery to thedivisions. In axilla, the posterior divisions ofall threeaxilla. The brachial plexus is formed by the anteriortrunks to form the posterior cord which is behind thebranches of the four lower cervical nerves(Cs-8) andaxillary artery; the anterior divisions of the superiormost fibers of the anterior branch of the first thoracicand middle trunks uniteto form the lateral cord whichnerve(T,).The plexus may be divided into the roots,is lateral to the axillary artery;the anteriordivision oftrunks, the divisions and the cords. The all of thethe inferior trunk passes downward along the medialanterior branches are the roots, as lie in the scaleneside of the axillary artery and forms the medial cord(-fissure, they are blended into three trunks: a supe-Fig. VI-5-7)rior trunk(Cs-6),a middle trunk(C,) and an inferiortrunk(Cg-T,) . As they pass beneath the clavicle, eachRightcommoncarotidaLeftvagusn.Right vagus nLeftphrenicnAnterior scalene mBrachialplexusAccessory phrenic rLeftsubclaviana.Right recurrent laryngeal nCardiac plexusSuperior vena cavsLeftrecurrentRightphreniclaryngealn.Pericardial bPhrenicoab-dominal br.DiaphragFig. VI-5-6The phrenic nerveroots of the brachial plexus in the neck. Long thoracicnerve descends along the lateral surface of the serra-.Branches of brachial plexustus anterior and supplies it. The damage of the longthoracic nerve results in paralysis of the serratus ante-According to the position, the branches of therior and "winging of the scapula".plexus are divided into two groups, the supraclavicu-2) Suprascapular nerve(Cs, Ce) The nervelar and the infraclavicular groups(Fig. VI-5-7).arises from the superior trunk of the plexus and runsbackward by passing through the scapular notch to(1) Branches of supraclavicular groupscapular region. It supplies the supraspinatus and theinfraspinatus.1) Long thoracic nerve(Cs-7) It arises from the扫描全能王创建
Chapter 5 Peripheral Nervous System · 379 .behind the scalenus medius. The nerve supplies the3) Dorsal scapular nerve(C4, C,)It comes fromthe roots of plexus, runs backward and downwardlevatorscapulaeand rhomboideus.ISuperior trunkMiddle trunkInferiortrunkPosterior divisionsPosteriorcordAnteriordivisionLateral cordIint.-Medial cordAxillary a.Long thoracicn.Radial n.Musculocu-taneous n.Ulnarn.MediannA diagram of the formation and main branches of brachial plexusFig. VI-5-7palmaris longus. It enters the palm by passing throughthe carpal canal finally and is deep to the palmar apo-(2) Branches of infraclavicular groupneurosis.(Fig. VI-5-8)The median nerve has no branches in the arm.In theforearm,itgives off themuscularbranches to1) Median nerve(Ce-g, T,) It is formed by twosupply most of the muscles in front of the forearmroots, one is from the lateral cord and another fromexcept the brachioradialis,the flexor carpi ulnaris andthe medial cord of the brachial plexus, which embracethe medial half of the flexor digitorum profundus.the axillary artery and unite each other in front or onAbove the wrist, the nerve gives rise to a small pal-the lateral side of the artery(Fig. VI-5-7, 8) .Aftermar cutaneous branch that is distributed to the skincombining the median nerve descends along the me-over the lateral part of the palm.In the palm, the me-dial side of the biceps brachii with the brachial artery.dian nerve is divided into a recurrent branch and threeIn the upper part of the arm, the nerve is lateral to thecommon palmar digital nerves(Fig. VI-5-8, 9, 10).artery,crosses the vessel anteriorly or posteriorly atThe recurrent branch innervates the thenar musclesthe middle part, and lies on the medial side of the ar-except the adductor pollicis.Each of common palmartery at the cubital fossa.Then it'enters the forearm bydigital nerves is divided into two proper palmar digpassing between the two heads of the pronator teres,ital nerves which distribute to the skin of the palmarand continues downward between the flexor digito-aspect of the thumb, second, third and the lateralrum superficialis and the flexor digitorum profundus.half of thefourth fingers, as well as the skin on theAt the wrist the median nerve emerges from the later-dorsum of the terminal phalanges. It also gives offal border of the flexor digitorum superficialis and liesmuscular branches to the first and second lumbricalbetween the tendons of the flexor carpiradialis and扫描全能王创建