Jalinūs (Galen), a Greek physician, writer, and philosopher, made significant contributions to the advancement of medical knowledge and conducted numerous dissections and observations of the brain and nerves, providing detailed descriptions of their structures and functions. His contributions to the nervous system anatomy and disease theory were significant, and he was the first to identify the brain as the site of termination for all five senses, which laid the foundation for further research into the functions of the nervous system. His theories on the nervous system were revolutionary, challenging prevailing beliefs and paving the way for further research, and his anatomical drawings and descriptions helped uncover the neuromuscular system under the control of the brain, as well as the structure and function of the respiratory and speech systems. Additionally, his studies on respiration and the recurrent laryngeal nerve solidified the idea that the brain is the site of rational power guiding human behavior. Furthermore, he differentiated sensory from motor nerves by palpation and believed the brain and nerves were responsible for sensation and thought. Jalinūs’ work on the nervous system, which included the vivisection of animals, laid the groundwork for future discoveries and advancements in the field. Despite these controversies, Jalinūs (Galen) remains significant and continues to influence modern medical practice. In this paper, we have reviewed the contributions of Jalinūs (Galen) to the advancement of knowledge in the anatomy of the nervous system.