The neurological examination is an important skill to acquire for all medical students. If performed correctly, it can help tremendously to narrow down the differential diagnoses which would subsequently guide investigations and management plan.
One important aspect of the neurological examination is to help localise the lesion. For example, in patients presenting with unilateral limb weakness, the lesion could be located anywhere along the corticospinal tract – its fibres of which orginate from the primary motor cortex and forms part of the corona radiata and the posterior limb of the internal capsule. The corticospinal tract subsequently enters the midbrain and pons, then decussates at the level of the medulla before entering the spinal cord. A lesion at any of these areas may therefore result in weakness. Weakness can also be due to dysfunction of the anterior horn cells or a disorder of the nerve root, plexus or nerve. Finally, a neuromuscular junction disorder or pathology affecting the muscles, bones, joints, tendons or ligaments may also result in weakness.
A good neurological examination would therefore include skills to ascertain whether there are upper or lower motor neuron signs accounting for the weakness as well as the distribution of the weakness. One should also proceed to ascertain whether there are any cortical signs, brainstem signs, sensory impairment as well as determine the distribution of impairment. With this information, one would be able to localize the lesion before proceeding to investigations to confirm the location of the lesion.
Undoubtedly, students find the neurological examination being one of the most difficult amongst the various examination skills. In the following videos and accompanying text, we hope to provide a simple approach in examining the neurological system.