Anterior spinothalamic tract

The spinothalamic tracts are ascending pathways primarily concerned with sensory function. They are responsible for transmitting pain, temperature, coarse (non-discriminative) touch and pressure sensations. The spinothalamic tracts can be separated into lateral and anterior tracts.

The anterior spinothalamic tract has some structural differences to its lateral counterpart and carries coarse touch and pressure sensations.

Gross anatomy

Peripheral connections

First-order neurones from peripheral receptors enter the spinal cord via the posterior roots. Axon terminals of these neurones synapse with second-order neurones whose cell bodies are located in the posterior grey horn of the cord. These second-order neurones that are considered the spinothalamic tract.

Course 

Different to the lateral spinothalamic tract, the second-order axons of the anterior spinothalamic tract decussate after ascending a few segments. The anterior spinothalamic tract lies in the anterior funiculus, medial to where the ventral spinal roots exit. It overlaps the vestibulospinal tract. Fibres of this tract are somatotopically organised for their entire course.

At the lower brainstem, the anterior tract joins the medial lemniscus. The neurones of the spinothalamic tract terminate in the ventral posterior nucleus of the thalamus after ascent. Here, they synapse with third-order neurones. These neurones project to the primary somatosensory area on the ipsilateral side of the cerebral cortex.

Related pathology

• Syringomyelia
• Intramedullary spinal tumour
• Spinal cord injury
• Brown-Séquard syndrome
• Transverse myelitis