History of discovering the facial nerve supply and neuroanatomy education today: Rudimentary details, controversies, and intricate connections

The nerve supply of the face has an intricate branching pattern that is often difficult to differentiate. The present study was undertaken to highlight the historical discoveries that helped understand the distribution of peripheral nerves in the face, identify the difficulty in comprehending the relevant anatomy due to complex details, and explore the relevance of historical details in addressing how the facial nerve is currently taught. Historically, Galen (third century AD) described the trigeminal nerve as dominant in regulating the motor and sensory supply of the face; however, he saw the facial nerve as being limited to a minor role in motor innervation, with a common origin alongside the vestibulocochlear nerve. This inaccurate concept persisted throughout the Middle Ages until the Early Renaissance in Europe. Thereafter, scientific studies by Fallopio and Eustachio (sixteenth century) and Sömmerring (eighteenth century) established the autonomous origin and extensive motor distribution of facial nerves. Despite considerable differences, Bell and Mayo (nineteenth century) agreed that the facial nerve is the nerve of facial expression. The discovery of facial nerve nuclei within the brainstem (early twentieth century) has allowed us to understand the motor, sensory, and autonomic components of the facial nerve. Advances in neurophysiology (twentieth century) have identified sensory fibers from the trigeminal nerve to the facial muscles (key to facial proprioception), in addition to motor innervation from branches of the facial nerve. This finding solved the puzzle regarding dual nerve supply of the facial muscles, often presenting as intricate connections. Similarly, the discovery of the upper motor neuron and lower motor neuron (late nineteenth and early twentieth centuries) solved the conundrum of facial palsy and the location of lesions in relation to the facial nerve nuclei. Comprehensive three-dimensional models elucidating the intricate details of the nerve supply to the face and facial nerve are effective in mapping, retaining, and reproducing relevant knowledge in academic and clinical practice. This methodology is currently used in anatomical sciences to teach the anatomy of the facial nerve.