Nerve root anomalies is an important topic which has been asked in DNB Orthopaedics Theory Examination . Here is a glimpse of what this is all about .
Type I. Intradural anastomosis between rootlets at different levels.
Type II. Anomalous origin of nerve roots : (a) cranial origin ; (b) caudal origin ; (c) combination of (a) and (b) affecting more than one nerve root (closely adjacent roots); and (d) conjoined nerve roots.
Type III. Extradural anastomosis between nerve roots.
Type IV. Extradural division of the nerve root
Please note :
1. The anomalous roots involved in Types II, III and IV may or may not leave the vertebral canal through their appropriate intervertebral foramina.
2. Nerve root anomalies may cause symptoms at more than one level as a result of pressure by, for example, a herniated intervertebral disc. Pressure on an abnormally situated nerve root may also give an incorrect indication of the level of disc herniation. A number of authors have reported cases of anomalous nerve roots in patients presenting with symptoms of intervertebral disc herniation, but in whom no obvious disc pathology was found at operation.
For more details of the topic here is an article that might give you a detailed insight about the subject : 411.full