114 articles
Dorsal root of spinal nerve
Dorsal root of spinal nerve (posterior root): the entirely sensory bundle of afferent axons, with cell bodies in the dorsal root ganglion, carrying touch, pain, and temperature from the periphery into the spinal cord's dorsal horn.
Edinger–Westphal nucleus
The Edinger–Westphal nucleus (E-W nucleus), described by Edinger in 1885 and Westphal in 1887, is a midbrain cell group whose preganglionic neurons control pupil constriction and lens accommodation.
Enteric nervous system
Enteric nervous system (ENS), the gut's "second brain": intrinsic network of over 500 million neurons and glia in the gastrointestinal wall, forming myenteric and submucosal plexuses, controlling motility and secretion autonomously of the CNS.
Entorhinal cortex
The entorhinal cortex is a medial temporal lobe region acting as the gateway between the hippocampus and neocortex, central to memory and containing grid cells for navigation.
Extrapyramidal system
Extrapyramidal system: historical grouping of basal ganglia, substantia nigra, red nucleus, subthalamic nucleus and descending tracts outside the corticospinal tract; criticized as obsolete, tied to antipsychotic EPS, VMAT2 inhibitor treatments.
Face
Face: front of the head, moved by the facial nerve (CN VII) with five motor branches plus taste, salivary, and lacrimal functions; facial nerve palsy, mostly Bell's palsy, is its main disorder.
Facial nerve
Facial nerve (CN VII), seventh cranial nerve with motor and intermediate roots; supplies facial expression muscles, taste anterior two-thirds of tongue, and lacrimal/submandibular/sublingual glands; exits via stylomastoid foramen; Bell's palsy.
Femoral nerve
The femoral nerve is a large lower limb nerve arising from the L2, L3, and L4 lumbar plexus roots and supplying the anterior thigh muscles.
Frontal lobe
Frontal lobe: anterior lobe of each cerebral hemisphere containing primary motor cortex, Broca's area, and prefrontal cortex; supports movement, expressive language, and divided prefrontal functions, not disproportionately enlarged in humans versus apes.
Glossopharyngeal nerve
Glossopharyngeal nerve (CN IX, nervus glossopharyngeus): ninth cranial nerve from the medulla exiting via the jugular foramen; supplies stylopharyngeus, parotid gland, posterior third of tongue taste, carotid sinus and body; linked to glossopharyngeal neuralgia.
Golgi tendon reflex
Golgi tendon reflex (inverse myotatic reflex, autogenic inhibition): spinal reflex where Golgi tendon organ Ib afferents disynaptically inhibit the contracting muscle's alpha motor neurons and excite antagonists; task-dependent, not just protective.
Human brain
Human brain: the three-pound central organ of the human nervous system, with about 100 billion nerve cells, an 80-percent-of-volume cortex, a restrictive blood-brain barrier, and a threefold size increase over two million years of hominin evolution.
Hypogastric plexus
The hypogastric plexus is a network of nerve fibers in the pelvis, divided into superior and inferior parts, that supplies autonomic innervation to the bladder, rectum, and reproductive organs.
Hypoglossal nerve
Hypoglossal nerve (cranial nerve XII): pure motor nerve from the medulla's hypoglossal nucleus, exiting via the hypoglossal canal, supplying all tongue muscles except palatoglossus; lesions deviate the tongue toward the lesion.
Hypothalamus
Hypothalamus: small ventral brain region below the thalamus, about 2% of brain volume, controlling the pituitary via releasing hormones (TRH, GnRH, CRH, dopamine) and homeostasis, appetite, temperature, and circadian rhythm; mapped in 2025 as HYPOMAP with 452 cell types.
Insular cortex
Insular cortex (insula, Island of Reil): cortical region hidden in the lateral sulcus, first described by Reil in 1809; hub for interoception, emotion, salience network, cognitive control, and social cognition.
Intercostal nerves
Intercostal nerves (nervi intercostales) are the anterior rami of thoracic spinal nerves T1-T11 running in the costal grooves; T7-T11 continue as thoracoabdominal nerves, T12 is the subcostal nerve, and T2 gives the intercostobrachial nerve.
Internal capsule
The internal capsule (capsula interna) is a compact band of white matter in each cerebral hemisphere where a small stroke can paralyze the opposite side of the body.
Intervertebral foramen
Intervertebral foramen (foramen intervertebrale, neural foramen): opening between adjacent vertebrae linking the spinal canal to the extraspinal region; bounded by pedicles, disc, and facet capsule; transmits spinal nerves and vessels; narrowing causes foraminal stenosis.
Lateral grey column
Lateral grey column (lateral horn, columna grisea lateralis medullae spinalis): small lateral projection of spinal cord grey matter at T1–L2/L3 containing preganglionic sympathetic neurons (intermediolateral cell column), with axons reaching the sympathetic trunk via white rami communicantes.
List of nerves of the human body
List of nerves of the human body: the 12 pairs of cranial nerves (olfactory through hypoglossal) and 31 pairs of spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal), plus major named peripheral nerves such as the sciatic, median, and vagus.
List of regions in the human brain
Regions of the human brain: cerebrum, cerebellum, brainstem (midbrain, pons, medulla), diencephalon, six cerebral lobes, cortical areas, and modern atlas parcellations such as AHRAv2 and Brodmann areas.
Lobes of the brain
Lobes of the brain: the six conventional divisions of each cerebral hemisphere (frontal, parietal, temporal, occipital, insula, limbic), their sulcal and imaginary-line boundaries, lobe-level functions, and the history and limits of functional localization.
Lumbar nerves
Lumbar nerves: five pairs of mixed spinal nerves L1-L5 exiting below their vertebrae, dividing into dorsal and ventral rami, forming the lumbar plexus (T12-L4) and, via the lumbosacral trunk, the sacral plexus.
Lumbar plexus
Lumbar plexus: somatic nerve network from L1-L4 ventral rami (often with T12 subcostal contribution) lying within psoas major; six branches including femoral and obturator nerves; mean variation prevalence 20.1%.
Mandibular nerve
Mandibular nerve (CN V3, nervus mandibularis), largest trigeminal division and the only one with a motor root; exits via foramen ovale, splits into anterior and posterior divisions, supplies mastication muscles, lower teeth, tongue, and is the target of the inferior alveolar nerve block.
Maxillary nerve
Maxillary nerve (V2), middle purely sensory division of the trigeminal nerve; exits via foramen rotundum to the pterygopalatine fossa, ends as the infraorbital nerve, and supplies midface, upper teeth, palate, and nasal mucosa.
Median nerve
Median nerve: terminal branch of the brachial plexus (lateral and medial cords, C5-T1) innervating most forearm flexors, thenar muscles, and the lateral 3.5 digits; compressed in carpal tunnel and pronator syndrome.
Medulla oblongata
The medulla oblongata is the lowermost part of the brainstem, continuous with the spinal cord, which controls breathing, heart rate, and blood pressure and houses nuclei for cranial nerves IX through XII.
Meninges
Meninges: the dura mater, arachnoid mater, and pia mater, the three membranes covering the brain and spinal cord, with their spaces, CSF, blood supply, and related conditions like meningitis and hematomas.