Anterior horn

From WikiMD's Wellness Encyclopedia

Anterior horn or ventral horn is a section of the spinal cord that contains motor neurons that send nerve impulses to the muscles. The anterior horn is one of the two roots of the spinal nerve that exits the spinal cord. The other root is the posterior (dorsal) horn, which receives sensory information from the body.

Etymology[edit | edit source]

The term "anterior horn" is derived from the Latin words "anterior," meaning "before" or "in front of," and "cornu," meaning "horn." The term "ventral horn" is derived from the Latin word "venter," meaning "belly" or "underside."

Structure[edit | edit source]

The anterior horn is located in the anterior (front) part of the spinal cord's grey matter. It contains large motor neurons, known as alpha motor neurons, which are responsible for sending nerve impulses to the muscles. These neurons are also known as lower motor neurons.

Function[edit | edit source]

The primary function of the anterior horn is to transmit motor information from the brain to the muscles. This information is sent via the alpha motor neurons, which stimulate muscle contraction. The anterior horn also plays a role in the reflex arc, a neural pathway that controls an immediate response to a particular stimulus.

Clinical significance[edit | edit source]

Damage to the anterior horn can result in a variety of motor neuron diseases, such as Amyotrophic lateral sclerosis (ALS), Spinal muscular atrophy (SMA), and Polio. These diseases are characterized by the degeneration of the alpha motor neurons in the anterior horn, leading to muscle weakness and atrophy.

Related terms[edit | edit source]

  • Posterior horn: The posterior horn is the other root of the spinal nerve that exits the spinal cord. It receives sensory information from the body.
  • Motor neuron: Motor neurons are nerve cells that transmit nerve impulses from the brain or spinal cord to the muscles.
  • Alpha motor neuron: Alpha motor neurons are large motor neurons located in the anterior horn of the spinal cord. They send nerve impulses to the muscles, causing them to contract.
  • Motor neuron disease: Motor neuron diseases are a group of neurological disorders that selectively affect motor neurons, the cells that control voluntary muscle activity.
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Contributors: Prab R. Tumpati, MD