Anterior horn (spinal cord)
Encyclopedia
The anterior horn of the spinal cord (also called the anterior cornu, anterior column or ventral horn) is the ventral
Anatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

 (front) grey matter
Grey matter
Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil , glial cells and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts...

 section of the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

. The anterior horn contains motor neuron
Motor neuron
In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system that project their axons outside the CNS and directly or indirectly control muscles...

s that affect the axial muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

s while the posterior horn receives information regarding touch and sensation. The anterior horn is where the cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 bodies
Soma (biology)
The soma , or perikaryon , or cyton, is the bulbous end of a neuron, containing the cell nucleus. The word "soma" comes from the Greek σῶμα, meaning "body"; the soma of a neuron is often called the "cell body"...

 of alpha motor neurons are located.

Pathology

It is these cells that are affected in the so-called "anterior horn diseases", namely amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...

, spinal muscular atrophy
Spinal muscular atrophy
Spinal Muscular Atrophy is a neuromuscular disease characterized by degeneration of motor neurons, resulting in progressive muscular atrophy and weakness. The clinical spectrum of SMA ranges from early infant death to normal adult life with only mild weakness...

, Charcot-Marie-Tooth disease
Charcot-Marie-Tooth disease
Charcot–Marie–Tooth disease- , known also as Morbus Charcot-Marie-Tooth, Charcot-Marie-Tooth neuropathy, hereditary motor and sensory neuropathy , hereditary sensorimotor neuropathy , or peroneal muscular atrophy, is an inherited disorder of nerves that takes different forms...

, poliomyelitis
Poliomyelitis
Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route...

, West Nile virus
West Nile virus
West Nile virus is a virus of the family Flaviviridae. Part of the Japanese encephalitis antigenic complex of viruses, it is found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, domestic...

, and progressive muscular atrophy
Progressive muscular atrophy
Progressive muscular atrophy is a rare subtype of amyotrophic lateral sclerosis or motor neurone disease which affects only the lower motor neurones. PMA is thought to account for around 4% of all ALS/MND cases...

. These motorneurons are also affected in Spinal and Bulbar Muscular Atrophy (Kennedy disease
Kennedy disease
Kennedy's disease or X-linked Spinal and Bulbar Muscular Atrophy or Spinobulbar Muscular Atrophy or X-Linked Bulbo-Spinal Atrophy is an X-linked recessive, slow progressing, neurodegenerative disease associated with mutation of the androgen receptor...

).

Anatomical details

The anterior column (anterior cornu, anterior horn), 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 column (columna lateralis; lateral cornu).
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