Testing motor and sensory function in the arms and legs requires knowledge of myotomes and dermatomes. Here is a guide to remembering the nerve roots of the upper and lower limbs.
A sound knowledge of nerve root function in the upper and lower limbs is essential for the assessment of many medical and surgical conditions. Spinal injuries, intervertebral disc disease with disc protrusion, poliomyelitis, Guillain-Barré syndrome and spina bifida are but a few examples. In these conditions, the physician has to ascertain that the clinical presentation represents nerve root involvement rather than peripheral nerve involvement and, more importantly, must be able to determine the nerve root level involved. A thorough knowledge of dermatomes and myotomes is mandatory to achieve this.