A Brief Neuroanatomy Glossary

Collections of Neurons

Gray matter A generic term for a collection of neuron cell bodies in the CNS. Neurons appear gray in a freshly dissected brain.

Cortex “Cortex” is Latin for “bark.” A cortex is a collection of neurons that forms a thin sheet, usually at an organ’s surface; e.g., cerebral cortex.

Nucleus “Nucleus” is Latin for “nut.” A clearly distinguishable mass of neurons in the brain; e.g., the lateral geniculate nucleus of the thalamus [relays information coming from the retina to the visual cortex].

Substantia A group of related neurons in the brain that are not as distinct as nuclei; e.g., substantia nigra [Latin for “black substance,” this group of cells in the brainstem is involved in the control of voluntary movement].

Locus (plural: loci) A small, well-defined group of cells; e.g., locus coeruleus [Latin for “blue spot,” a brain stem cell group involved in arousal.

Ganglion (plural: From the Greek for “knot.”A collection of neurons in the PNS; e.g., dorsal

ganglia) root ganglia which contain the cell bodies of sensory axons entering the spinal cord. The basal ganglia are the only nuclei in the brain called “ganglia”.

Collections of Axons

Nerve A bundle of axons in the PNS; e.g., the thirty-one pairs of spinal nerves.

White matter A generic term for CNS axons. Axons appear white in a freshly dissected brain.

Tract A collection of CNS axons having a common origin and a common destination. The first term indicates the point of origin, the last term indicates the destination; e.g., corticospinal tract [which originates in the cerebral cortex and ends in the spinal cord].

Bundle A collection of axons that run together but do not necessarily have the same origin and destination; e.g., medial forebrain bundle [which connects a variety of cells within the cerebrum and brain stem]. Also called a fasiculus.

Capsule A collection of axons that connect the cerebrum with the brain stem; e.g., internal capsule [which connects the brain stem and cerebral cortex].

Commissure Any collection of axons that connects one side of the brain with the other; e.g., the anterior commissure [which connects the left and right temporal lobes].

Lemniscus A collection of CNS axons that meanders through the brain like a ribbon; e.g., medial lemniscus [which carries touch information from the spinal cord through the brain stem].

General [G indicates a greek root word; L indicates a latin root word]

Agnosia a (not), gnosis (knowledge). [G]

Alexia a (not), lexis (word). [G]

-algia Greek suffix for pain.

Aqueduct aqua (water), ductus (leading). [L]

Arachnoid arachne (spider), eidos (resemblance). [G]

Arch- Greek prefix for ancient.

Archicortex arch (ancient), cortex (bark) [L]. Three layered cortex of the hippocampus.

Arcuate arcus (bow). [L]

Astrocyte astron (star), kytos (cell). [G]

Ataxia a (not), taxia (orderly). [G]

Ballism ballein (to throw) [G. Ballismos, jumping about]

Brachium brachium (arm) [L]

Carotid Karotides, the carotid arteries, from karoo (to put to sleep). [G]

Caudate cauda (tail). [L]

Cerebellum diminutive of cerebrum–little brain. [L]

Chiasm the Greek letter chi (P) is cross-shaped.

Chorea chorea (dance). [L from the Greek choreia]

Cingulum cingulum (belt). [L]

Cistern cisterna (a well). [L]

Claustrum claustrum (enclosure). [L]

Cornu cornu (horn). [L]

Corona Radiata corona (crown or garland), radiata (radiating). [G]

Corpus Callosum corpus (body), callosum (hard). [L]

Cortex cortex (bark) [L]

Crista crista (crest). [L]

Cuneate cuneatus (wedge-shaped). [L]

Decussation The Roman numeral X is called deca.

Dendrite dendron (branching figure or tree). [G]

Dentate dentatus (tooth shaped). [L]

Diencephalon dia (through), enkephalos (brain). [G]

Dura Mater dura (hard), mater (mother–who protects) [L] Also pachymeninx.[G]

Dyskinesia dis (improper), kinesia (motion) [G]

Edema oidema (swelling). [G]

Epi- Greek prefix for upon, over, above.

Fasiculus fasiculus (bundle) [L]

Fornix fornix (arch) [L]

Genu genu (knee). [L]

Glia glia (glue). [G]

Glossal glossa (tongue). [G]

Gracilis gracilis (slender). [L]

Gyrus gyros (ring, circle) [G]

Hippocampus hippos (horse), kampos (sea). [G]

Hypo- Greek prefix for under, below.

Insula insula (island). [L]

Internuncial inter (between), nuncio (messenger). [L]

Lamina lamina (layer, thin plate). [L]

Lemniscus lemniskos (ribbon, band). [G]

Lentiform Lens shaped. [L]

Limbic limbus (border or edge). [L]

Lingula lingula (little tongue). [L]

Lumbar lumbus (loin or flank). [L]

Macula macula (spot). [L]

Mammillary mamma (breast). [L]

Meninx meninx (membrane). [G]

Mesencephalon meso (middle), enkephalos (brain). [G]

Metencephalon meta (after), enkephalos (brain). [G]

Meyelencephalon myelos (marrow, medulla), enkephalos (brain). [G]

Neo- neos (new or recent). [G]

Neocortex neos (new), cortex (bark). Six layered cortex of the cerebral hemispheres.

Neuropil neuron (nerve), pilos (felt). [G]

Oligodendroglia oligo (few), dendron (branch), glia (glue). [G]

Pachymenix pachy (thick), menix (membrane). [G] Also dura mater.

Paleo- Greek prefix for old.

Paleocortex paleo (old), cortex (bark). Cortex with 4/5 layers of neurons found in the parahippocampal gyrus)

Pallidus pallidus (pale). [L]

Peduncle ped (foot, limb, stalk). [L]

Petrous petra (rock). [L] also petros [G].

Pia mater pia (soft), mater (mother). [L]

Pineal pinea (pine cone). [L]

Pons pons (bridge). [L]

Prosencephalon proso (forward), enkephalos (brain). [G]

Ramus ramus (branch) [L]

Rectus rectus (straight). [L]

Reticular reticulum (small net). [L]

Rhinencephalon rhin (nose), enkephalos (brain). [G]

Rhombencephalon rhombos (rhomboid or diamond shaped), enkephalos (brain). [G]

Rubro ruber (red). [L]

Sacral sacer (holy, sacred). [L]

Sagittal sagitta (arrow). [L]

Sella turcica sella (saddle), turcica (Turkish). [L]

Septum septum (partition). [L]

Substantia nigra substantia (substance), nigra (black). [L]

Syn- Greek prefix for together, joined.

Synapse syn (together), hapto (to clasp). [G]

Tapetum tapete (carpet). [L]

Tectum tectum (roof). [L]

Telencephalon telos (end), enkephalos (brain). [G]

Temporal tempus (time). The temple shows the passage of time when it grays. [L]

Tentorium tentorium (tent). [L]

Tubercle L diminutive of tuber (swelling)

Vagus vagus (wandering) [L]

Velum velum (covering). [L]

Ventricle ventriculus (little chamber). [L]

Vermis vermis (worm). [L]

Vertebra vertere (verto, to turn) [L]

Sources

Bear, M. F., Connors, B. W., & Paradiso, M. A. (1996). Neuroscience: Exploring the brain. Baltimore: Williams & Wilkins.

Gertz, S. David (1996). Neuroanatomy Made Easy and Understandable. Gaithersburg: Aspen Publishers.

Stedman, T. L. (1995). Stedman’s Medical Dictionary (26^th edition). Baltimore: Williams & Wilkins.