Anterior Horn (spinal Cord)
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The anterior grey column (also called the anterior cornu, anterior horn of spinal cord, motor horn or ventral horn) is the front column of
grey matter Grey matter 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, and capillaries. Grey matter is distingui ...
in the
spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...
. It is one of the three
grey column The grey column refers to a somewhat ridge-shaped mass of grey matter in the spinal cord. This presents as three columns: the anterior grey column, the posterior grey column, and the lateral grey column, all of which are visible in cross-section o ...
s. The anterior grey column contains
motor neuron A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectl ...
s that affect the
skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s while the
posterior grey column The posterior grey column (posterior cornu, dorsal horn, spinal dorsal horn, posterior horn, sensory horn) of the spinal cord is one of the three grey columns of the spinal cord. It receives several types of sensory information from the body, incl ...
receives information regarding touch and sensation. The anterior grey column is the column where the
cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...
bodies Bodies may refer to: * The plural of body * ''Bodies'' (2004 TV series), BBC television programme * Bodies (upcoming TV series), an upcoming British crime thriller limited series * "Bodies" (''Law & Order''), 2003 episode of ''Law & Order'' * ...
of
alpha motor neurons Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their con ...
are located.


Structure

The anterior grey column, directed forward, is broad and of a rounded or quadrangular shape. Its posterior part is termed the base, and its anterior part the head, but these are not differentiated from each other by any well-defined constriction. It is separated from the surface of the medulla spinalis by a layer of white substance which is traversed by the bundles of the anterior nerve roots. In the thoracic region, the postero-lateral part of the anterior column projects laterally as a triangular field, which is named the
lateral grey column The lateral grey column (lateral column, lateral cornu, lateral horn of spinal cord, intermediolateral column) is one of the three grey columns of the spinal cord (which give the shape of a butterfly); the others being the anterior and posterio ...
.


Clinical significance

It is these cells that are affected in the following diseases, –
amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...
,
spinal and bulbar muscular atrophy Spinal and bulbar muscular atrophy (SBMA), popularly known as Kennedy's disease, is a debilitating neurodegenerative disorder resulting in muscle cramps and progressive weakness due to degeneration of motor neurons in the brainstem and spinal cor ...
,
Charcot–Marie–Tooth disease Charcot–Marie–Tooth disease (CMT) is a hereditary motor and sensory neuropathy of the peripheral nervous system characterized by progressive loss of muscle tissue and touch sensation across various parts of the body. This disease is the mos ...
,
progressive muscular atrophy Progressive muscular atrophy (PMA), also called Duchenne–Aran disease and Duchenne–Aran muscular atrophy, is a disorder characterised by the degeneration of lower motor neurons, resulting in generalised, progressive loss of muscle function. PM ...
, all
spinal muscular atrophies Spinal muscular atrophies (SMAs) are a genetically and clinically heterogeneous group of rare debilitating disorders characterised by the degeneration of lower motor neurons (neuronal cells situated in the anterior horn of the spinal cord) and ...
,
poliomyelitis Poliomyelitis, commonly shortened to polio, is an infectious disease caused by the poliovirus. Approximately 70% of cases are asymptomatic; mild symptoms which can occur include sore throat and fever; in a proportion of cases more severe sym ...
, and
West Nile virus West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family ''Flaviviridae'', from the genus ''Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The virus ...
.


Pharmacological interaction

The anterior grey column is the target for some spasmolytic medications.
Norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...
release here, (as induced by
cyclobenzaprine Cyclobenzaprine (sold under the brand name Flexeril, among others) is a medication used for muscle spasms from musculoskeletal conditions of sudden onset. It is not useful in cerebral palsy. It is taken by mouth. Use is not recommended for mor ...
) reduces spasms by innervation (reducing nerve activity) of
alpha motor neurons Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their con ...
via interaction with gamma fibers.


See also

*
Alpha motor neuron Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their con ...
*
Beta motor neuron Beta motor neurons (β motor neurons), also called beta motoneurons, are a kind of lower motor neuron, along with alpha motor neurons and gamma motor neurons. Beta motor neurons innervate intrafusal fibers of muscle spindles with collaterals to ex ...
*
Gamma motor neuron A gamma motor neuron (γ motor neuron), also called gamma motoneuron, or fusimotor neuron, is a type of lower motor neuron that takes part in the process of muscle contraction, and represents about 30% of ( Aγ) fibers going to the muscle. Like al ...
*
Posterior grey column The posterior grey column (posterior cornu, dorsal horn, spinal dorsal horn, posterior horn, sensory horn) of the spinal cord is one of the three grey columns of the spinal cord. It receives several types of sensory information from the body, incl ...


Additional images

Image:Gray687.png, Section 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 ...
through the lower part of the
decussation of the pyramids In neuroanatomy, the medullary pyramids are paired white matter structures of the brainstem's medulla oblongata that contain motor fibers of the corticospinal and corticobulbar tracts – known together as the pyramidal tracts. The lower limit o ...


References

{{Authority control Spinal cord