Lumbosacral radiculopathy

LS is more frequent than cervical, and is more common to have involvement of multiple roots. The L5 root is most common (40 %) then S1 (26 %) then L4 (19%) then L3 (16 %). Beware of diabetes mimicking a radiculopathy. Nerve conductions are not that helpful nor is SEP. Needle EMG is best. Below with each root is the order of findings of muscle abnormality at each level, in order, with instructions how to reach some of the muscles listed. L3- ADD, ILI, RF, VL, VM (first two were abnormal in almost all) L4- VM, AT, VL , RF, ADD (percentages were not much more than 50 on most of these) L5 AT (27/40), PER (22/25), FDL (20/25), PT (10/12), GME (25/35), TFL (half) and then almost always normal were RF, VL, GMA, MG (7/40) S1 PER (7/11 was best), GME PT GMA MG AT (5/26) very rarely if ever: VL RF ADD ILI. Paraspinals are very important and are slightly better than the cervicals. Finding muscles: insertion and action ILI insert 2 fingerbreadths lateral to femoral artery and 1 fb below inguinal ligament; flex thigh RF insert anterior thigh, midway between superior border of patella and anterior superior iliac spine. TFL (sup gluteal n, L4) insert 2 fingerbreadths anterior to greater trochanter; abduct thigh VL -- lateral thigh, one handbreadth above patella ; lift heel with knee extended. VM-- 4 fb proximal to sup-med angle of the patella. Lift heel with knee extended. GMA- insert one to three inches midway between greater trochanter and sacrum; extend knee with hip flexed. GME- one inch distal to midpoint of iliac crest; abduct thigh. ADD-- 4 fb distal to pubic tubercle , adducts limb.