What is the Difference Between Anterior and Lateral Corticospinal Tract

The main difference between the anterior and lateral corticospinal tract is that the anterior corticospinal tract sends nerve fibers to the axial muscles. In contrast, the lateral corticospinal tract sends nerve fibers to the extremity muscles. 

Anterior and lateral corticospinal tract are two types of corticospinal tract. They are a collection of axons, that carry signals for the voluntary muscular movements from the cerebral cortex to the spinal tract.  

Key Areas Covered

1. What is Anterior Corticospinal Tract
– Definition, Structure, Function
2. What is Lateral Corticospinal Tract
– Definition, Structure, Function
3. Similarities Between Anterior and Lateral Corticospinal Tract
– Outline of Common Features
4. Difference Between Anterior and Lateral Corticospinal Tract
– Comparison of Key Differences

Key Terms 

Anterior Corticospinal Tract, Lateral Corticospinal Tract

What is Anterior Corticospinal Tract

The anterior corticospinal tract is a descending motor tract containing upper motor neurons. Other names for the anterior corticospinal tract include:

• The medial corticospinal tract.
• Direct pyramidal tract.
• Ventral corticospinal tract.
• Bundle of tract.
• Anterior cerebrospinal fasciculus.

However, the anterior corticospinal tract is a small bundle of descending nerve fibers that connects the cerebral cortex to the spinal cord. Motor signals transmitted through descending tracts are pathways. Significantly, the anterior corticospinal tract is small and contains 10% of the nerves in the corticospinal tract. On the other hand, it is close to the anterior median fissure. Also, it only occurs in the upper part of the spinal cord. Gradually, it diminishes in size and ends in the middle of the thoracic region.

Figure 1: Pyramidal Tracts

Furthermore, the primary function of the anterior corticospinal tract is to adjust the posture by controlling voluntary movements. It mainly controls the voluntary movements of the truncal or axial body musculature. It transmits the motor signals. The upper motor neurons in the brain send these motor signals to lower motor neurons which then directly innervate muscle to move. 

What is Lateral Corticospinal Tract

The lateral corticospinal tract is the most significant part of the corticospinal tract. 90% of the corticospinal tract is the lateral corticospinal tract. Other names for the lateral corticospinal tract include crossed pyramidal tract and the lateral cerebrospinal fasciculus. Significantly, it extends through the spinal cord. The transverse region of the lateral corticospinal tract appears as an oval area. Also, it occurs in the front of the posterior column. In addition, it occurs medial to the posterior spinocerebellar tract. Upper and lower motor neurons are the two types of descending motor pathways.

Figure 2: The motor Tract

Moreover, the function of the lateral corticospinal tract is to carry motor signals from the brain to the spinal cord. Also, the lateral corticospinal tract sends these motor signals from the spinal cord to the target organs. In that way, the lateral corticospinal tract sends motor signals to the extremity muscles.  

Similarities Between Anterior and Lateral Corticospinal Tract

• Anterior and lateral corticospinal tract are two types of corticospinal tract.
• They are the largest descending tract found in humans.
• They are a collection of axons.
• They carry movement-related information from the cerebral cortex to the spinal tract.  

Difference Between Anterior and Lateral Corticospinal Tract

Definition

Anterior corticospinal tract refers to a small bundle of descending nerve fibers that connect the cerebral cortex to the spinal cord. In contrast, the lateral corticospinal tract refers to a corticospinal tract that contains over 90% of the fibers present in the corticospinal tract and runs the length of the spinal cord.

Composition

The anterior corticospinal tract contains 10% of the corticospinal tract, while the lateral corticospinal tract contains 90% of the corticospinal tract.

Decussate at the Level of the Medulla Oblongata

The anterior corticospinal tract decussates at the level of the medulla oblongata, while the lateral corticospinal tract does not decussate at the level of the medulla oblongata.

Descending Tract

The anterior corticospinal tract descends at the middle of the thoracic region, while the lateral cerebrospinal tract runs through the entire spinal cord.   

Function

The anterior corticospinal tract helps adjust the posture by controlling the voluntary movements of the axial or truncal body musculature. In contrast, the lateral corticospinal tract controls the voluntary movement of contralateral limbs.

Conclusion

In brief, the anterior and lateral corticospinal tracts are two corticospinal tracts that occur in the spinal cord. They send movement-related information from the cerebral cortex to the spinal tract. However, the anterior corticospinal tract contains 10% of the corticospinal neurons. Also, it controls the voluntary muscle movements of the axial body. But, the lateral corticospinal tract contains 90% of the corticospinal tract. Furthermore, it sends voluntary muscular movement information to the contralateral limbs. Therefore, the main difference between anterior and lateral corticospinal tract is the type of innervation.

References:

1. Javed K, Reddy V, Lui F. Neuroanatomy, Lateral Corticospinal Tract. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. 

Image Courtesy:

1. “Spinal cord tracts – English” By Polarlys and Mikael Häggström – Own work (CC-BY SA 3.0) via Commons Wikimedia
2. “Gray764” By Henry Vandyke Carter – Own Work (Public Domain) via Commons Wikimedia