The lateral grey column (lateral column, lateral cornu, lateral horn of spinal cord, intermediolateral column) is one of the three

grey column The grey columns are three regions of the somewhat ridge-shaped mass of grey matter in the spinal cord. These regions present as three columns: the anterior grey column, the posterior grey column, and the lateral grey column, all of which ...

s of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

(which give the shape of a butterfly); the others being the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

and posterior grey columns. The lateral grey column is primarily involved with activity in the sympathetic division of the autonomic

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

system. It projects to the side as a triangular field in the

thoracic The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main ...

and upper

lumbar In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm (anatomy), diaphragm and the sacrum. Naming and location The lumbar region is sometimes referred to as the lowe ...

regions (specifically T1- L2) of the postero-lateral part of the

anterior grey column The grey columns are three regions of the somewhat ridge-shaped mass of grey matter in the spinal cord. These regions present as three columns: the anterior grey column, the posterior grey column, and the lateral grey column, all of which are ...

Background information

Nervous system

The

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

is the system of

neurons A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

, or nerve cells that relay electrical signals through the brain and body. A nerve cell receives signals from other nerve cells through tree-branch-like extensions called

dendrites A dendrite (from Greek δένδρον ''déndron'', "tree") or dendron is a branched cytoplasmic process that extends from a nerve cell that propagates the electrochemical stimulation received from other neural cells to the cell body, or soma ...

and passes signals through a long extension called an

axon An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, ...

(or nerve fiber).

Synapses In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending o ...

are places where one cell's axon passes information to another cell's

dendrite A dendrite (from Ancient Greek language, Greek δένδρον ''déndron'', "tree") or dendron is a branched cytoplasmic process that extends from a nerve cell that propagates the neurotransmission, electrochemical stimulation received from oth ...

by sending chemicals called

neurotransmitters A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are rele ...

across a small gap called a

synaptic cleft Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in neuromuscular junction, muscles or glands. Chemical synapses allow neurons to form biological neural ...

. Synapses occur in various locations, including

ganglia A ganglion (: ganglia) is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system, this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system, there a ...

(singular: ganglion), which are masses of nerve cell bodies. Preganglionic nerve cells in the

sympathetic nervous system The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous sy ...

(all of which come from the lateral grey column), use the neurotransmitter

acetylcholine Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...

, while postganglionic sympathetic nerve cells use

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The ...

Grey matter Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil ( dendrites and unmyelinated axons), glial cells ( astrocytes and oligodendrocytes), synapses, ...

in the brain and spinal cord is any accumulation of cell bodies and

neuropil Neuropil (or "neuropile") is any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies. The most prevalent ...

(neuropil is tissue rich in nerve cell bodies and dendrites).

White matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...

consists of

nerve tract A nerve tract is a bundle of nerve fibers (axons) connecting Nucleus (neuroanatomy), nuclei of the central nervous system. In the peripheral nervous system, this is known as a nerve fascicle, and has associated nervous tissue, connective tissue. T ...

s (groups of axons) and commissures (tracts that cross the brain's midline).

Sympathetic nervous system

The

is divided into the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

(brain and spinal cord) and the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of Bilateria, bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside t ...

(everything else). The peripheral nervous system is divided into the

somatic nervous system The somatic nervous system (SNS), also known as voluntary nervous system, is a part of the peripheral nervous system (PNS) that links brain and spinal cord to skeletal muscles under conscious control, as well as to sensory receptors in the skin ...

(voluntary processes) and the

autonomic nervous system The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates viscera, internal organs, smooth muscle and glands. The autonomic nervo ...

(involuntary processes). The autonomic nervous system is divided into the

parasympathetic nervous system The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The autonomic nervous system is responsible for regulat ...

(normal functioning) and the

(emergency functioning). The lateral grey column mediates the functions of the sympathetic nervous system.

Spinal cord

The

is divided into 31 segments, located between the

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

. Each segment is defined by a posterior root entering it and an anterior root exiting it. Each of these roots is the end of a spinal nerve connecting the spinal cord to the body. The

vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...

is divided into four groups of vertebrae: (from top to bottom) cervical,

, and sacral.Dafny, N. (1997). Anatomy of the spinal cord. http://neuroscience.uth.tmc.edu/s2/chapter03.html

Structure

The lateral grey column is present at 17 levels of the spinal cord, specifically through levels T1-L2 (sympathetic outflow) as well as through levels S2-S4 (parasympathetic outflow).Dlugos, C. (1999). ''Autonomic nervous system.'

/ref> Both these segments are located within the first thoracic vertebra to the first or second lumbar vertebra as the spinal cord ends here and the nerves form the

cauda equina The cauda equina () is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enl ...

Sympathetic Circuit from the Lateral Horn

The lateral grey column is composed of sympathetic preganglionic visceral motor neurons which are part of the

. An in-depth study of the lateral grey columns in the thoracic region of rats revealed two types of cells. One cell type was characterized by many

mitochondria A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

, an indented

nucleus Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucleu ...

, and a long

endoplasmic reticulum The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryote, eukaryotic cell, and has many other important functions such as protein folding. The word endoplasmic means "within the cytoplasm", and reticulum is Latin for ...

, while the other cell type had an increased cytoplasmic density and a short endoplasmic reticulum. Lateral column

axon terminals An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, ...

were found to contain

noradrenaline Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" (from ...

storage granules and could be divided into four types. Type one terminals contained a few large and many small granular

vesicles Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle In a neuron, synaptic vesicles (or neurotransmitter vesicles) s ...

, and type two terminals had many large vesicles and barely noticeable granules. Type three terminals contained small, spherical vesicles and no granules, and type four were the rarest terminals that had flattened vesicles with small and large granules. The cells of the intermediolateral cell column are fusiform or star-shaped, and of a medium size. The intermediolateral cell column exists at vertebral levels T1 - L2 and mediates the entire sympathetic innervation of the body. In the upper part of the cervical region and lower part of the

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

, as well as in the third and fourth sacral vertebrae, this column is again differentiated.

Functions

The lateral grey column's connections mediate the functions of the sympathetic nervous system (SNS), which changes cardiac, pulmonary, hepatic (liver), and gastrointestinal activities to prepare the body for emergency situations (although the sympathetic system is always active to some extent, including in the absence of a stressful environment, to maintain the appropriate level of sympathetic function). When the brain responds to potential threats by sending signals to lateral grey column cells, the lateral column passes on the signals to initiate a variety of physiological changes that prepare the body for a “

fight-or-flight The fight-or-flight or the fight-flight-freeze-or-fawn (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first describ ...

” response. Hairs stand up to conserve heat. The gut relaxes and

digestion Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into th ...

slows so that more energy can be directed toward dealing with the threatening situation. The

adrenal medulla The adrenal medulla () is the inner part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of chromaffin cells that secrete catecho ...

is activated and releases

epinephrine Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands a ...

(adrenaline) into the bloodstream, where it mediates many changes, such as the preparation of muscles for emergency activity. A variety of smooth muscles relax; for example, the muscles wrapped around the

bronchioles The bronchioles ( ) are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start of the respiratory zone delivering air to t ...

of the lungs relax, allowing more

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

to enter the bloodstream.

Heart rate Heart rate is the frequency of the cardiac cycle, heartbeat measured by the number of contractions of the heart per minute (''beats per minute'', or bpm). The heart rate varies according to the body's Human body, physical needs, including the nee ...

increases to ensure all cells are supplied quickly with the substances they need. The

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

produces

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

(sugar) to fuel the muscles. Blood vessels contract (

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vesse ...

), which reduces bleeding and conserves body heat (the exception is blood vessels fueling large muscles that would be used in running or fighting). The pupils dilate, improving vision.

Perspiration Perspiration, also known as sweat, is the fluid secreted by sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and Apocrine sweat gland, apocrine glands. The eccrine sweat glands are distribu ...

increases in certain areas of the body (the purpose of this is not yet fully understood, but there is some evidence that the odor produced by this sweat serves as a signal to other individuals).

Sympathetic

The lateral grey column plays an important role in the

sympathetic division The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous sy ...

of the visceral (autonomic) motor system. Neuron cell bodies in the lateral column send their axons to synapse on sympathetic ganglia that innervate autonomic and pelvic organs; in fact, all preganglionic neurons in the sympathetic nervous system originate in the lateral grey column. Neurons in the upper and middle thoracic segments control sympathetic activity in organs in the head and thorax, while neurons in the lower thoracic and upper lumbar segments control abdominal and pelvic organs and targets in the lower extremities. Slightly myelinated

preganglionic nerve fibers In the autonomic nervous system, nerve fibers from the central nervous system to the ganglion are known as preganglionic nerve fibers. All preganglionic fibers, whether they are in the sympathetic division or in the parasympathetic division, are ...

(aka visceral efferent fibers) leave the lateral grey column through the ventral roots and promptly form fourteen aggregates called white rami communicantes, also known as white communicating rami, which eventually enter the

sympathetic trunk The sympathetic trunk (sympathetic chain, gangliated cord) is a paired bundle of nerve fibers that run from the base of the skull to the coccyx. It is a major component of the sympathetic nervous system. Structure The sympathetic trunk lies just ...

, a structure next to the

that consists of paired chains of sympathetic

connected by nerve fibers. Most often, the fibers from the lateral grey column will travel along the sympathetic trunk until they synapse on one of the trunk's ganglia, which then passes on the information via postganglionic fibers in a gray ramus communicans. 31 pairs of gray rami communicantes exit the sympathetic trunk to join the 31 pairs of

spinal nerves A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into ...

and travel to targets such as

sweat glands Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...

, hair follicles, and

blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...

. Some fibers, such as those in the cardiac nerves that innervate the heart, reach the target organ directly, without first joining a gray ramus communicans. Other fibers from lateral grey column neurons pass through the sympathetic trunk without synapsing there. The greater

splanchnic nerve The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system ( visceral efferent fibers) as well as sensory fibers from the organs ( viscera ...

leaves the vertebral levels T5-T9 and synapses in the abdomen in the celiac ganglia, which innervates the

celiac artery The celiac () artery (also spelled coeliac in British English), also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic verte ...

(splanchnic nerves are the nerves that innervate thoracic and abdominal viscera). The lesser splanchnic nerve travels from the vertebral levels T10-T11 to the abdomen's superior mesenteric ganglia, which innervates the

superior mesenteric artery In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the ...

, and to the aorticorenal ganglion. The least, or lowest, splanchnic nerve connects the T12 level to the

renal plexus The renal plexus is a complex network of nerves formed by filaments from the celiac ganglia and plexus, aorticorenal ganglia, lower thoracic splanchnic nerves and first lumbar splanchnic nerve and aortic plexus. The nerves from these sourc ...

. The

lumbar splanchnic nerves The lumbar splanchnic nerves are splanchnic nerves that arise from the lumbar ganglia (the lumbar part of the sympathetic trunk) and travel to an adjacent plexus near the aorta. They originate from L1 and L2. Together with fibres from the aorti ...

from the upper two lumbar segments synapse in the abdomen on the inferior mesenteric ganglia, associated with the

inferior mesenteric artery In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The region ...

. In addition, some thoracic fibers in the splanchnic nerves innervate the adrenal medulla, a ganglion in the abdomen that mediates the sympathetic response to stress. Axons from the lateral grey column release

at their synapses. This can excite or inhibit the postsynaptic cell, depending on the type of acetylcholine receptor in its membrane. Postganglionic cells (that is, nerve cells innervated in ganglia by lateral column neurons) typically release

(noradrenaline) on their targets; these synapses can also be either excitatory or inhibitory. The lateral grey column receives input signals from preganglionic, myelinated fibers from

viscera In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...

(internal organs), which course through prevertebral ganglia (between the visceral organ and the sympathetic chain) and

paravertebral ganglia The sympathetic ganglia, or paravertebral ganglia, are autonomic ganglia of the sympathetic nervous system. Ganglia are 20,000 to 30,000 Afferent nerve fiber, afferent and Efferent nerve fiber, efferent nerve cell bodies that run along on either s ...

(in the sympathetic chain), white rami communicantes, and dorsal roots to synapse on cells of the intermediolateral cell column in the lateral horn. Lateral grey column nerve cells also receive signals from the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

and from neurons in the

hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...

, a brain area involved in mediating many physiological functions and emotional states.Harting, John. "Hypothalamus," ''Neuroscience Coursebook''. University of Wisconsin. January 21, 2005. Web. http://www.neuroanatomy.wisc.edu/coursebook/neuro2(2).pdf

Clinical significance

Horner's syndrome Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...

is characterized by small pupils, sunken eyes, partially drooping eyelid, and dryness of the skin on the face. It is caused by problems in autonomic pathways such as damage to the lateral grey column. Progressive autonomic failure is a disease associated with autonomic disturbances due to selective neuronal degeneration. A study estimated the number of nerve cells in the lateral grey columns of 21 people with progressive autonomic failure in comparison with a control group. This same study found that an average of 75 percent of the lateral column cells were lost in people with progressive autonomic failure.

Multiple system atrophy Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by tremors, slow movement, muscle rigidity, postural instability (collectively known as parkinsonism), autonomic dysfunction and ataxia. This is caused by progr ...

(MSA) is an adult onset disorder that is a sporadic and progressive. MSA is characterized by a combination of

ataxia Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in e ...

parkinsonism Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia (slowed movements), Rigidity (neurology), rigidity, and balance disorder, postural instability. Both hypokinetic features (bradykinesia and akinesia) and hyperkinetic f ...

, and

autonomic dysfunction Dysautonomia, autonomic failure, or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This condition may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and b ...

. A study did a comparison with the lateral grey column nerve cell count between 15 cases of patients with MSA and a control group. All cases of MSA had lost over 50 percent of their lateral horn cells which shows the involvement of the intermediolateral columns in MSA. Lichtheim's disease (also known as subacute combined degeneration) is the result of a

vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. One of eight B vitamins, it serves as a vital cofactor (biochemistry), cofactor in DNA synthesis and both fatty acid metabolism, fatty acid and amino a ...

deficiency and is associated with

pernicious anemia Pernicious anemia is a disease where not enough red blood cells are produced due to a deficiency of Vitamin B12, vitamin B12. Those affected often have a gradual onset. The most common initial symptoms are Fatigue, feeling tired and weak. Other ...

. The disease is characterized by the degeneration of both the lateral and posterior columns, which results in symptoms such as a spastic ataxic gait and paranoia.Benzel, E., Waxman, C., Stephen, G., Byrne, T. N. "Diseases of the Spine and Spinal Cord." Oxford University Press, USA, 2000. Patients may also feel tingling or weakness in their limbs and torso.

References

{{Authority control Spinal cord