Dorsal column-medial lemniscus pathway

General Information
Latin
Greek
TA98
TA2
FMA
Details
System	Nervous system
Artery
Vein
Nerve
Lymphatic drainage
Precursor
Function	Sensory pathway
Identifiers
Clinical significance
Notes

The dorsal column-medial lemniscus pathway (DCML) is a major sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, and proprioception from the body to the brain.

Structure

The DCML pathway is composed of two main parts: the dorsal columns and the medial lemniscus.

Dorsal Columns

The dorsal columns are located in the spinal cord and consist of two tracts: the fasciculus gracilis and the fasciculus cuneatus. The fasciculus gracilis carries sensory information from the lower half of the body, while the fasciculus cuneatus carries information from the upper half.

Medial Lemniscus

The medial lemniscus is a band of fibers that extends from the medulla oblongata to the thalamus. It is formed by the crossing of the internal arcuate fibers in the medulla.

Function

The primary function of the DCML pathway is to transmit sensory information related to fine touch, vibration, and proprioception. This information is crucial for spatial awareness and motor control.

Pathway

1. **First-order neurons**: Sensory receptors in the skin and joints send signals through the dorsal root ganglia into the spinal cord, where they ascend in the dorsal columns.

2. **Second-order neurons**: In the medulla oblongata, the first-order neurons synapse with second-order neurons in the nucleus gracilis and nucleus cuneatus. The axons of these neurons cross to the opposite side of the medulla and form the medial lemniscus.

3. **Third-order neurons**: The medial lemniscus ascends to the thalamus, where it synapses with third-order neurons in the ventral posterolateral nucleus. These neurons project to the primary somatosensory cortex in the parietal lobe of the cerebral cortex.

Clinical Significance

Damage to the DCML pathway can result in loss of fine touch, vibration, and proprioceptive sensations. This can occur due to spinal cord injury, stroke, or multiple sclerosis.

See also

• Spinothalamic tract
• Somatosensory system
• Proprioception

References

Dale,

 Neuroscience, 
  
 Oxford University Press, 
 2018, 
  
  
 ISBN 978-1605353807,

External links

• Dorsal column-medial lemniscus pathway on WikiMD

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