Lateral horn of spinal cord

Lateral Horn of the Spinal Cord

The lateral horn is a region of gray matter located in the spinal cord. It is situated between the dorsal horn and the ventral horn, and it is primarily involved in the autonomic nervous system (ANS) function. In this article, we will explore the anatomy, function, and clinical significance of the lateral horn.

Anatomy

The lateral horn is found in the thoracic and upper lumbar regions of the spinal cord. It is composed of a cluster of cell bodies known as the intermediolateral cell column (IMLCC). These cell bodies give rise to preganglionic sympathetic neurons, which play a crucial role in the sympathetic division of the ANS.

The lateral horn is organized into segments, with each segment corresponding to a specific level of the spinal cord. The segments are named according to the vertebral level they are associated with. For example, the lateral horn at the T1 level is referred to as the T1 lateral horn.

Function

The main function of the lateral horn is to regulate the sympathetic outflow of the ANS. Sympathetic preganglionic neurons originating in the lateral horn extend their axons out of the spinal cord through the ventral root. These axons then synapse with postganglionic neurons in the sympathetic ganglia located outside the spinal cord.

The lateral horn is responsible for controlling various physiological responses, including the fight-or-flight response. When the body perceives a threat or stressor, the sympathetic division of the ANS is activated, leading to increased heart rate, dilation of blood vessels, and mobilization of energy reserves.

Clinical Significance

Damage or dysfunction of the lateral horn can have significant clinical implications. For example, a lesion in the lateral horn at a specific level of the spinal cord can result in disruption of sympathetic innervation to specific organs or regions of the body.

One notable condition associated with lateral horn dysfunction is Horner's syndrome. This syndrome is characterized by a combination of symptoms, including drooping of the eyelid (ptosis), constriction of the pupil (miosis), and decreased sweating on one side of the face. It occurs due to interruption of sympathetic innervation to the eye and face, often as a result of damage to the lateral horn at the cervical level of the spinal cord.

Conclusion

The lateral horn of the spinal cord is a crucial component of the autonomic nervous system. Its role in regulating sympathetic outflow and coordinating physiological responses is essential for maintaining homeostasis in the body. Understanding the anatomy and function of the lateral horn can provide valuable insights into various clinical conditions and help guide appropriate treatment strategies.