Spinal tract of trigeminal nerve

Tractus spinalis nervi trigemini

Definition

Muhammad A. Javaid

The spinal tract of trigeminal nerve consists of first-order neurons of the trigeminal sensory system that transmit pain and temperature information from the face, descending through the brainstem to reach the spinal trigeminal nucleus in the medulla and upper spinal cord.

The trigeminal nerve (cranial nerve V) is primarily responsible for transmitting sensory information from the face and controlling motor functions like biting and chewing. The first-order neurons, which carry pain and temperature signals via the V1, V2, or V3 divisions, enter the brainstem at the pons region. Their cell bodies are located in the trigeminal ganglion outside the brainstem. Within the brainstem, these neural fibers descend before synapsing with second-order neurons in the spinal trigeminal nucleus, found mainly in the medulla oblongata and extending into the upper spinal cord. This descending pathway of first-order neurons is known as the spinal tract of trigeminal nerve and is located lateral to the spinal trigeminal nucleus. After synapsing in the spinal trigeminal nucleus, the second-order neurons convey pain and temperature information to the VPM nucleus of the thalamus via the trigeminal lemniscus.

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