 crocodile b diagn par Heritage B Mer in to dень B C and post-ganglianic lesions. Pre-ganglianic lesions are the lesions proximal to the neural foramen that is proximal to the dorsal nor root ganglion. These are the root apples on injuries like long thoracic mer palsy because of C5, C6 and C7 root involvement or frennic nor palsy because of C3, C4 and C5 root involvement or horner syndrome because of T1 root apples. In contrast post-ganglianic lesions are the lesions distal to the neural foramen or distal to the dorsal root ganglion. These are the apples on the terminal nerves. But this distinction of pre-ganglianic lesions and post-ganglianic lesions is of critical importance because you all know the pre-ganglianic lesions are located in the central nervous system proximal to the dorsal root ganglion and in the central nervous system the regeneration of the neurons are absent so the prognosis of the pre-ganglianic plexopathy is very grave. But in contrast the post-ganglianic lesions are located beyond the dorsal nor root ganglion are in the peripheral nervous system and in the peripheral nervous system the regeneration of the neurons are far better so the prognosis of the post-ganglianic plexopathy are far better than the pre-ganglianic ones. So here comes the role of radiology because MRI is the best modality for diagnosing and localizing the site injury in case of brachial plexopathy because the localization whether it is a pre-ganglianic one or post-ganglianic one determines the prognosis and the management and out of the all MRI sequences the star inversion recovery is going to be the best sequence for diagnosis and localizing brachial plexopathy. As far as contrast is concerned intravenous gadolinum is administered in patients with brachial plexopathy due to tumors and mass but gadolinum is not generally administered in patient of traumatic brachial plexopathy. Coming to the anatomy as we all know brachial plexus is formed by the joining of the roots of C5, C6, C7, C8 and T1 roots then all these roots form the three trunks upper middle and lower trunks and from each trunks there occurs anterior and posterior division and all these division join to from three cords, medial cord, lateral cord and posterior cord and all these cord finally give the terminal branches but clinically as we see the clinically we divide the brachial plexopathy into supra-clobucular legions and intra-clobucular legions so the supra-clobucular plexopathy involve the roots and the trunks and the intra-clobucular legions involve the cords and the terminal branches as we see in the supra-clobucular legions there will be involvement of the roots like the involvement of the fending nerve roots, long thoracic nerve and dorsal scopula nerve also the involvement of the trunks like upper middle and lower trunks could be involved or involvement of the nerves from the trunk like nerve to subclavius and supra-scopula nerve so all this comes under the supra-clobucular brachial plexopathy but in case of intra-clobucular brachial plexopathy there will be involvement of the cord and the terminal branches like the branches from the lateral cord like lateral pectoral nerve, medial pectoral nerve and lateral root of medial nerve so all this comes from the lateral cord also from the median cord then online nerve could be involved and from the posterior cord like axillary nerve, radial nerve injury, thoracodorsal nerve injury, upper subscopula nerve injury this all comes under the infraclobucular brachial plexopathy but as far as radiology is concerned we have to only distinguish between whether it's a pre-ganglionic injury or a post-ganglionic injury coming to the pre-ganglionic injury as we see the pre-ganglionic injury is near the spinal cord so there will be edema of the spinal cord with some hemorrhage in the nerve root they will show blooming on gary and susceptibility divided imaging and there will be characteristically there will be pseudo meningosil formation pseudo meningosil formation which will appear t2 star hyper intensity near the nerve root so pseudo meningosil formation is a characteristic of pre-ganglionic brachial plexopathy here the image is showing the pseudo meningosil formation which is t2 bright and as indirect sign we can we can see the enhancement of the paraspinal muscle also then then coming to the post-ganglionic injury as we all see the post-ganglionic injury is the injury beyond the dorsal nerve ganglia so as a MRI finding the nerve roots will be normal at origin but they will be indistinct distally and and all the terminal nerves there will appear t to hyper intense and there will be thickening and some edema they will also see some edema as indirect evidence we can see clavicular fracture and in sometimes there could be neoplastic etiology like panco tumors so panco tumor generally causes post-ganglionic brachial plexopathy here is the here is the t2 star t2 star coronal section showing the hyper intensity and edema in the terminal nerves so this is a post-ganglionic type of injury coming to the case discussion the case one that there is a 35 year male who is presented with right clavicular mass with weakness in the right upper limb here in the star image there is it shows the hyper intense mass lesion in the right clavicular lesion region with hyper intense nerve with some kind of edema so it's in the in the clavicular and infraclavicular part with t2 hyper intense t2 star hyper intensity and with edema and so it is a suggestive of post-ganglionic type of brachial plexopathy thickening edema of the nerves and t2 hyper intensity at the level of clavicular then coming to also in the axial section axial section of in the right side also shows hyper intense t2 hyper intense mass arising from the clavicular so this is a type of post-ganglionic type brachial plexopathy which is a favorable prognosis prognostically is favorable then coming to case 2 case 2 is a one-year female one-year old female disease with left upper limb abnormal movement there is history of stress in use also also there when we see the MRI look at the MRI in the in the star coronal image there along the nerve roots there is histic t2 t2 star hyper intensity with pseudo meningosil formation so once we see the pseudo meningosil formation pseudo meningosil formation is a characteristics of pre-ganglionic injury so here is the hyper intensity along the along the left spinal cord nerve roots so these are the with pseudo meningosil formation these are characteristics of pre-ganglionic injury and and as we all know the pre-ganglionic injuries are of grave prognosis also in the axial section in the axial t2 fat suppress section also there is there is hyper intensity t2 star hyper intensity along the left side of the spinal cord in the spinal root region with pseudo meningosil formation so pseudo meningosil formation with t2 hyper intensity in the spinal nerve root region is characterates of pre-ganglionic type of brachial plexopathy it is it is a very poor prognosis and so prognostically because it involves it is in the central nervous system which has no regeneration potential so it is a very poor prognosis so the MRI is most importantly as conclusion we can say the MRI apart from the diagnosis it is able to localize whether it is a pre-ganglionic injury or post-ganglionic injury it will determine the prognosis and management point of view these all are my references