RESEARCH STARTER

Neuroanatomy

Neuroanatomy is the specialized study of the structure and organization of the nervous system in both humans and animals. This complex system, which includes the brain and spinal cord, operates through a network of electrical impulses that transmit information throughout the body. The human brain, weighing approximately 3.5 pounds, is an intricate organ comprising billions of neurons and trillions of supportive glial cells, responsible for regulating vital functions and processing sensory information. Neuroanatomy encompasses both the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which connects the CNS to the rest of the body.

Historically, the understanding of neuroanatomy has evolved significantly, beginning from ancient civilizations that held varied beliefs about the brain's significance. Key figures such as Hippocrates and Galen laid foundational theories, while Renaissance scholars like Leonardo da Vinci advanced anatomical illustrations and insights. Modern neuroanatomy benefits from advanced imaging and microscopic technologies, allowing deeper exploration of the nervous system's intricacies. Understanding neuroanatomy not only enhances knowledge of brain function and disorders but also fosters appreciation for the complexity of human biology and its variations across species.

Full Article

Anatomy is the study of an organism’s structure and includes several branches of study. Neuroanatomy is the specific study of the organization of the nervous system in both animals and humans. The nervous system is an extremely complex network of electrical impulses and chemical neurotransmitters that relays messages to and from the brain. The brain then interprets that information and sends out instructions for a response to the rest of the body.

The history of neuroanatomy is lengthy and well-documented. Ancient Egyptians, Romans, and Greeks all explored the human body and its organ functions. The oldest document mentioning the brain is a medical papyrus from Egypt. Known as the Edwin Smith Surgical Papyrus, it was written around 1600–1700 BCE but was believed to be a copy of an older document originated between  3000 and 2500 BCE. Scholars, including Hippocrates, Plato, Alcmaeon of Croton, Galen, and Leonardo da Vinci, were fascinated by and made extensive studies of neuroanatomy. Since that time, medical science and understanding regarding the human brain and nervous system have expanded greatly. With modern technology, neuroanatomical exploration can extend to the smallest neuron and map out the functions of the various sections of the brain.

Brief History

Ancient peoples held various beliefs concerning the seat of human thought, emotion, intelligence, and the senses. Many ancient Egyptians believed the brain was a useless lump of gooey tissue, and they removed the mummies’ brains quickly and with no sentiment. The dominant belief among Egyptians and Mesopotamians was that the heart was the organ of greatest importance. The author of the Edwin Smith Surgical Papyrus described two severe head wounds that had exposed brain tissue and how the living brain was fluttering and throbbing under the surgeon’s hands. Furthermore, the document describes the effects of brain injury on gross motor functions, such as speech and movement, and includes a physical description of the anterior fontanelle, the meninges, and cerebrospinal fluid (CSF).

By the fifth century BCE, Hippocrates taught that sensations, emotions, and thoughts originate from the brain. He believed that it was because of the brain that humans suffered ailments such as insomnia or insanity. Ultimately, he declared that the brain was the most powerful organ within the human body. Alcmaeon of Croton traced the main sensory nerves back to the brain, and his teachings encouraged the practice of dissection and anatomical study. Two early Greek physicians were the first to make systematic and scientific studies of human remains. Herophilus and Erasistratus offered the first glimpse of the structure of the human brain and nervous system.

Aristotle made the first mention of the cerebellum in the fourth century BCE, and Galen wrote about its functions. Erasistratus distinguished the cerebrum at the front of the skull from the cerebellum, which is at the back.

The earliest known illustration of the brain in Western history is included in an eleventh-century manuscript. Discoveries in neuroanatomy continued to be made over the centuries, and during the Renaissance period, Leonardo da Vinci made detailed drawings of the brain. After an experiment with ox brains in the early 1500s, he discovered that the ventricles within them contain CSF. Vesalius published the first drawing of the base of the brain, while Archangelo Piccolomini recognized the distinction between the white and gray matter of the brain.

It was not until the invention of technology capable of examination on a molecular level that scientists could advance their understanding of the structure and function of the nervous system. Applying microscopic and electrical technology provided insight into the neurological network. Modern techniques like functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and optogenetics have revolutionized how scientists research and map the brain. These advances have allowed neuroanatomy to significantly contribute to the scientific community’s understanding of the physiological aspects of neurological diseases like Alzheimer’s disease and Parkinson’s disease, as well as a deeper understanding and treatments following a stroke. For example, in 2012, scientists first identified and imaged the glymphatic system—the brain’s system responsible for waste clearance and distributing essential nutrients, immune cells, and signaling molecules throughout the central nervous system (CNS), primarily during sleep. This finding offered researchers new information about the brain’s health mechanisms, which have major implications for neurodegenerative disease research.

Overview

Cognitive neuroscience is a neuroscience subfield that integrates neuroanatomy, neurophysiology, and psychology to study cognition. Neuroanatomy is a foundational branch of neuroscience encompassing structural and functional nervous system mapping. The anatomical aspects of the nervous system include the brain, spinal cord, and their related parts. Although the adult human brain only weighs roughly 3.5 pounds (1.5 kilograms), it contains billions of neurons, less than 85 billion glial (support) cells, and about 100 to 500 trillion synapses. Visually, the brain is pinkish-gray and mushy, a double handful of fluttering, quivering tissue that is the control center for the nerve network. It is protected by bone, membrane, and fluid, and uses 20 percent of the body’s oxygen and glucose supply. Without either, the brain often suffers irreversible damage from cellular death.

The brain has four main areas: the brain stem, cerebellum, diencephalon, and cerebrum. It is divided into two hemispheres, linked by the corpus callosum. Parts of the brain have ridges (gyri) and grooves (sulci), along with fissures that compartmentalize the regions of the brain. Further into the brain is the ventricular system, composed of hollow chambers called ventricles, which are filled with fluid. It is protected by CSF, which cushions and buoys the brain, aids in waste clearance and homeostasis, and contains a special blood barrier that prevents chemicals and some hormones from entering the brain. The brain stem contains the medulla oblongata, which holds the nerves that affect senses and motor skills that run from the spinal cord to the brain. It regulates basic functions such as breathing. Also within the brain stem are the pons, which relay messages from the cortex and the cerebellum, and the midbrain. The midbrain contains the visual and auditory reflex centers.

The cerebellum’s two hemispheres coordinate the body’s movement, balance, cognition, language, and emotional regulation. The diencephalon holds the thalamus, hypothalamus, subthalamus, and epithalamus. These organs control bodily functions and mental processes, such as the autonomic nervous system, sensory input, sleeping, and information processing. A deep groove, the longitudinal fissure, divides the left and right hemispheres and each hemisphere consists of four lobes with specialized functions: frontal (decision-making, motor control, personality, and speech or Broca’s area), occipital (vision processing), temporal (hearing, memory, and language comprehension or Wernicke’s area), and parietal (sensory processing and spatial navigation).

The spinal cord connects the brain with the rest of the body via the brain stem and is a vital link in the nervous system network. It has two rows of nerve roots on each side, forming thirty-one pairs of spinal nerves. It has five different regions: the cervical, thoracic, lumbar, sacral, and coccygeal. The thirty-one segments of the spine are relative to the thirty-one nerve pairs: eight cervical nerves, twelve thoracic nerves, five lumbar nerves, five sacral nerves, and one coccygeal nerve.

Neuroanatomy also includes the structure and study of the nerve network and its purpose. The nervous system comprises the CNS and the peripheral nervous system (PNS). CNS contains the brain and spinal cord, while PNS describes the nerve pathways throughout the rest of the body. Further divisions of the PNS include the somatic, or voluntary, system and the autonomic nervous system. These refer to the conscious functions of the body as well as the unconscious functions, such as digestion.

A neuron, or nerve cell, conducts electrochemical messages from one part of the body to another. They are composed of a cell body and two types of fibers: dendrites and axons. They work in tandem with glial cells, also called neuroglia, which offer support and protection. Several types of glial cells support the blood-brain barrier, neural repair, immune response, and metabolic support.


Bibliography

Basinger, Hayden, and Jeffery P. Hogg. “Neuroanatomy, Brainstem.” StatPearls, National Library of Medicine, 4 July 2023, www.ncbi.nlm.nih.gov/books/NBK544297. Accessed 9 Mar. 2026.

Daniels, Patricia. Body: The Complete Human: How It Grows, How It Works, and How to Keep It Healthy and Strong. National Geographic, 2007, pp. 226–61.

Duque-Parra, Jorge Eduardo. “Functional Neuroanatomy: The First Daughter of Neuroscience and the Mother of Neural Science.” The Anatomical Record, vol. 265, no. 4, 2001, pp. 250–53, doi:10.1002/ar.10037. Accessed 9 Mar. 2026.

Gray, Henry. Gray’s Anatomy: The Classic Collector’s Edition. Crown Publishers, 1977, pp. 639–810.

“Introduction to Neuroanatomy.” UBC Neuroanatomy, Functional Neuroanatomy, neuroanatomy.ca/neurointro.html. Accessed 9 Mar. 2026.

Karenberg, A. “Cerebral Localization in the Eighteenth Century.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 248–53.

Llamas, Andreu. The Nervous System. Gareth Stevens, 1999.

Ludwig, Parker E., et al. “Neuroanatomy, Central Nervous System (CNS).” StatPearls, National Library of Medicine, 10 Oct. 2022, www.ncbi.nlm.nih.gov/books/NBK442010. Accessed 9 Mar. 2026.

Macaulay, David, and Richard Walker. The Way We Work: Getting to Know the Amazing Human Body. Houghton Mifflin, 2008, pp. 149–215.

“Neuroanatomy: The Basics.” Dana Foundation, 20 Sept. 2023, dana.org/resources/neuroanatomy-the-basics. Accessed 9 Mar. 2026.

Rose, F. Clifford. “Cerebral Localization in Antiquity.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 239–47, doi:10.1080/09647040802025052. Accessed 9 Mar. 2026.

Steinberg, D. “Cerebral Localization in the Nineteenth Century—The Birth of a Science and Its Modern Consequences.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 254–61.

van Middendorp, Joost J., et al. “The Edwin Smith Papyrus: A Clinical Reappraisal of the Oldest Known Document on Spinal Injuries.” European Spine Journal: Official Publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, vol. 19, no. 11, 2010, pp. 1815–23, doi:10.1007/s00586-010-1523-6. Accessed 9 Mar. 2026.

von Bartheld, Christopher S., et al. “The Search for True Numbers of Neurons and Glial Cells in the Human Brain: A Review of 150 Years of Cell Counting.” The Journal of Comparative Neurology, vol. 524, no. 18, 2016, pp. 3865–95, doi:10.1002/cne.24040. Accessed 9 Mar. 2026.

Full Article

Anatomy is the study of an organism’s structure and includes several branches of study. Neuroanatomy is the specific study of the organization of the nervous system in both animals and humans. The nervous system is an extremely complex network of electrical impulses and chemical neurotransmitters that relays messages to and from the brain. The brain then interprets that information and sends out instructions for a response to the rest of the body.

The history of neuroanatomy is lengthy and well-documented. Ancient Egyptians, Romans, and Greeks all explored the human body and its organ functions. The oldest document mentioning the brain is a medical papyrus from Egypt. Known as the Edwin Smith Surgical Papyrus, it was written around 1600–1700 BCE but was believed to be a copy of an older document originated between  3000 and 2500 BCE. Scholars, including Hippocrates, Plato, Alcmaeon of Croton, Galen, and Leonardo da Vinci, were fascinated by and made extensive studies of neuroanatomy. Since that time, medical science and understanding regarding the human brain and nervous system have expanded greatly. With modern technology, neuroanatomical exploration can extend to the smallest neuron and map out the functions of the various sections of the brain.

Brief History

Ancient peoples held various beliefs concerning the seat of human thought, emotion, intelligence, and the senses. Many ancient Egyptians believed the brain was a useless lump of gooey tissue, and they removed the mummies’ brains quickly and with no sentiment. The dominant belief among Egyptians and Mesopotamians was that the heart was the organ of greatest importance. The author of the Edwin Smith Surgical Papyrus described two severe head wounds that had exposed brain tissue and how the living brain was fluttering and throbbing under the surgeon’s hands. Furthermore, the document describes the effects of brain injury on gross motor functions, such as speech and movement, and includes a physical description of the anterior fontanelle, the meninges, and cerebrospinal fluid (CSF).

By the fifth century BCE, Hippocrates taught that sensations, emotions, and thoughts originate from the brain. He believed that it was because of the brain that humans suffered ailments such as insomnia or insanity. Ultimately, he declared that the brain was the most powerful organ within the human body. Alcmaeon of Croton traced the main sensory nerves back to the brain, and his teachings encouraged the practice of dissection and anatomical study. Two early Greek physicians were the first to make systematic and scientific studies of human remains. Herophilus and Erasistratus offered the first glimpse of the structure of the human brain and nervous system.

Aristotle made the first mention of the cerebellum in the fourth century BCE, and Galen wrote about its functions. Erasistratus distinguished the cerebrum at the front of the skull from the cerebellum, which is at the back.

The earliest known illustration of the brain in Western history is included in an eleventh-century manuscript. Discoveries in neuroanatomy continued to be made over the centuries, and during the Renaissance period, Leonardo da Vinci made detailed drawings of the brain. After an experiment with ox brains in the early 1500s, he discovered that the ventricles within them contain CSF. Vesalius published the first drawing of the base of the brain, while Archangelo Piccolomini recognized the distinction between the white and gray matter of the brain.

It was not until the invention of technology capable of examination on a molecular level that scientists could advance their understanding of the structure and function of the nervous system. Applying microscopic and electrical technology provided insight into the neurological network. Modern techniques like functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and optogenetics have revolutionized how scientists research and map the brain. These advances have allowed neuroanatomy to significantly contribute to the scientific community’s understanding of the physiological aspects of neurological diseases like Alzheimer’s disease and Parkinson’s disease, as well as a deeper understanding and treatments following a stroke. For example, in 2012, scientists first identified and imaged the glymphatic system—the brain’s system responsible for waste clearance and distributing essential nutrients, immune cells, and signaling molecules throughout the central nervous system (CNS), primarily during sleep. This finding offered researchers new information about the brain’s health mechanisms, which have major implications for neurodegenerative disease research.

Overview

Cognitive neuroscience is a neuroscience subfield that integrates neuroanatomy, neurophysiology, and psychology to study cognition. Neuroanatomy is a foundational branch of neuroscience encompassing structural and functional nervous system mapping. The anatomical aspects of the nervous system include the brain, spinal cord, and their related parts. Although the adult human brain only weighs roughly 3.5 pounds (1.5 kilograms), it contains billions of neurons, less than 85 billion glial (support) cells, and about 100 to 500 trillion synapses. Visually, the brain is pinkish-gray and mushy, a double handful of fluttering, quivering tissue that is the control center for the nerve network. It is protected by bone, membrane, and fluid, and uses 20 percent of the body’s oxygen and glucose supply. Without either, the brain often suffers irreversible damage from cellular death.

The brain has four main areas: the brain stem, cerebellum, diencephalon, and cerebrum. It is divided into two hemispheres, linked by the corpus callosum. Parts of the brain have ridges (gyri) and grooves (sulci), along with fissures that compartmentalize the regions of the brain. Further into the brain is the ventricular system, composed of hollow chambers called ventricles, which are filled with fluid. It is protected by CSF, which cushions and buoys the brain, aids in waste clearance and homeostasis, and contains a special blood barrier that prevents chemicals and some hormones from entering the brain. The brain stem contains the medulla oblongata, which holds the nerves that affect senses and motor skills that run from the spinal cord to the brain. It regulates basic functions such as breathing. Also within the brain stem are the pons, which relay messages from the cortex and the cerebellum, and the midbrain. The midbrain contains the visual and auditory reflex centers.

The cerebellum’s two hemispheres coordinate the body’s movement, balance, cognition, language, and emotional regulation. The diencephalon holds the thalamus, hypothalamus, subthalamus, and epithalamus. These organs control bodily functions and mental processes, such as the autonomic nervous system, sensory input, sleeping, and information processing. A deep groove, the longitudinal fissure, divides the left and right hemispheres and each hemisphere consists of four lobes with specialized functions: frontal (decision-making, motor control, personality, and speech or Broca’s area), occipital (vision processing), temporal (hearing, memory, and language comprehension or Wernicke’s area), and parietal (sensory processing and spatial navigation).

The spinal cord connects the brain with the rest of the body via the brain stem and is a vital link in the nervous system network. It has two rows of nerve roots on each side, forming thirty-one pairs of spinal nerves. It has five different regions: the cervical, thoracic, lumbar, sacral, and coccygeal. The thirty-one segments of the spine are relative to the thirty-one nerve pairs: eight cervical nerves, twelve thoracic nerves, five lumbar nerves, five sacral nerves, and one coccygeal nerve.

Neuroanatomy also includes the structure and study of the nerve network and its purpose. The nervous system comprises the CNS and the peripheral nervous system (PNS). CNS contains the brain and spinal cord, while PNS describes the nerve pathways throughout the rest of the body. Further divisions of the PNS include the somatic, or voluntary, system and the autonomic nervous system. These refer to the conscious functions of the body as well as the unconscious functions, such as digestion.

A neuron, or nerve cell, conducts electrochemical messages from one part of the body to another. They are composed of a cell body and two types of fibers: dendrites and axons. They work in tandem with glial cells, also called neuroglia, which offer support and protection. Several types of glial cells support the blood-brain barrier, neural repair, immune response, and metabolic support.


Bibliography

Basinger, Hayden, and Jeffery P. Hogg. “Neuroanatomy, Brainstem.” StatPearls, National Library of Medicine, 4 July 2023, www.ncbi.nlm.nih.gov/books/NBK544297. Accessed 9 Mar. 2026.

Daniels, Patricia. Body: The Complete Human: How It Grows, How It Works, and How to Keep It Healthy and Strong. National Geographic, 2007, pp. 226–61.

Duque-Parra, Jorge Eduardo. “Functional Neuroanatomy: The First Daughter of Neuroscience and the Mother of Neural Science.” The Anatomical Record, vol. 265, no. 4, 2001, pp. 250–53, doi:10.1002/ar.10037. Accessed 9 Mar. 2026.

Gray, Henry. Gray’s Anatomy: The Classic Collector’s Edition. Crown Publishers, 1977, pp. 639–810.

“Introduction to Neuroanatomy.” UBC Neuroanatomy, Functional Neuroanatomy, neuroanatomy.ca/neurointro.html. Accessed 9 Mar. 2026.

Karenberg, A. “Cerebral Localization in the Eighteenth Century.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 248–53.

Llamas, Andreu. The Nervous System. Gareth Stevens, 1999.

Ludwig, Parker E., et al. “Neuroanatomy, Central Nervous System (CNS).” StatPearls, National Library of Medicine, 10 Oct. 2022, www.ncbi.nlm.nih.gov/books/NBK442010. Accessed 9 Mar. 2026.

Macaulay, David, and Richard Walker. The Way We Work: Getting to Know the Amazing Human Body. Houghton Mifflin, 2008, pp. 149–215.

“Neuroanatomy: The Basics.” Dana Foundation, 20 Sept. 2023, dana.org/resources/neuroanatomy-the-basics. Accessed 9 Mar. 2026.

Rose, F. Clifford. “Cerebral Localization in Antiquity.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 239–47, doi:10.1080/09647040802025052. Accessed 9 Mar. 2026.

Steinberg, D. “Cerebral Localization in the Nineteenth Century—The Birth of a Science and Its Modern Consequences.” Journal of the History of the Neurosciences, vol. 18, no. 3, 2009, pp. 254–61.

van Middendorp, Joost J., et al. “The Edwin Smith Papyrus: A Clinical Reappraisal of the Oldest Known Document on Spinal Injuries.” European Spine Journal: Official Publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, vol. 19, no. 11, 2010, pp. 1815–23, doi:10.1007/s00586-010-1523-6. Accessed 9 Mar. 2026.

von Bartheld, Christopher S., et al. “The Search for True Numbers of Neurons and Glial Cells in the Human Brain: A Review of 150 Years of Cell Counting.” The Journal of Comparative Neurology, vol. 524, no. 18, 2016, pp. 3865–95, doi:10.1002/cne.24040. Accessed 9 Mar. 2026.

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