Internal arcuate fibers

Internal Arcuate Fibers

Diagram showing the course of the arcuate fibers. The internal arcuate fibers are not labeled, but are seen arching upward to the right of the anterior median fissure.

The Internal Arcuate Fibers (also known as internal arcuate tract or lemniscus tract) are a collection of axons in the brainstem. They are part of the sensory system and play a crucial role in transmitting information from the body to the brain.

Anatomy

The internal arcuate fibers are located in the medulla oblongata, one of the three parts of the brainstem. They are a part of the lemniscus system, which is a complex network of nerve fibers that transmit sensory information from the body to the brain.

The fibers originate from the gracile nucleus and cuneate nucleus, which are clusters of neurons located in the medulla oblongata. From there, they cross over (decussate) to the opposite side of the medulla and ascend to the thalamus, a part of the brain that processes and relays sensory information.

Function

The primary function of the internal arcuate fibers is to transmit sensory information from the body to the brain. This information includes touch, vibration sense, and proprioception (the sense of the relative position of one's own parts of the body).

The fibers carry this information from the gracile and cuneate nuclei to the thalamus. From there, the information is relayed to the somatosensory cortex, the part of the brain responsible for processing sensory information.

Clinical Significance

Damage to the internal arcuate fibers can result in a loss of sensation, particularly touch, vibration sense, and proprioception. This can occur due to a variety of conditions, including stroke, multiple sclerosis, and neurodegenerative diseases.

See Also

• Brainstem
• Medulla oblongata
• Sensory system