![]() The third order neurones carry the sensory signals from the thalamus to the ipsilateral primary sensory cortex of the brain. They travel superiorly within the spinal cord, synapsing in the thalamus. Pain and temperature fibres – enter the lateral spinothalamic tract.Īlthough they are functionally distinct, these tracts run alongside each other, and they can be considered as a single pathway.Crude touch and pressure fibres – enter the anterior spinothalamic tract.After synapsing with the first order neurones, these fibres decussate within the spinal cord, and then form two distinct tracts: The second order neurones carry the sensory information from the substantia gelatinosa to the thalamus. They then synapse in the nucleus gracilis of the medulla oblongata.įig 2 – The spinothalamic tracts, which carry the sensory modalities of crude touch, pressure, pain and temperature. Signals from the lower limb (below T6) – travel in the fasciculus gracilis (the medial part of the dorsal column).Signals from the upper limb (T6 and above) – travel in the fasciculus cuneatus (the lateral part of the dorsal column). They then synapse in the nucleus cuneatus of the medulla oblongata.There are two different pathways which the first order neurones take: The first order neurones carry sensory information regarding touch, proprioception or vibration from the peripheral nerves to the medulla oblongata. There are three groups of neurones involved in this pathway – first, second and third order neurones. In the brainstem, it is transmitted through the medial lemniscus. ![]() In the spinal cord, information travels via the dorsal (posterior) columns. Its name arises from the two major structures that comprise the DCML. The dorsal column-medial lemniscal pathway (DCML) carries the sensory modalities of fine touch (tactile sensation), vibration and proprioception. The Dorsal Column-Medial Lemniscal Pathway In this article, we shall look at the anatomy of the ascending tracts, and consider their clinical implications.
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