Where does the pathway for dorsal column afferents Decussate?
The first-order axons make contact with second-order neurons of the dorsal column nuclei (the gracile nucleus and the cuneate nucleus) in the lower medulla. The second-order neurons send their axons to the thalamus….Dorsal column–medial lemniscus pathway.
| Dorsal column-medial lemniscus pathway | |
|---|---|
| Acronym(s) | DCML |
| Anatomical terms of neuroanatomy |
Where does decussation occur in the pathway carrying nociceptive information from the body?
There is a decussation (i.e., axons crossing the midline to the opposite side of the spinal cord or brain stem) in each somatosensory pathway below the level of the thalamus.
Where does sensory decussation occur?
There is a decussation (i.e., axons crossing the midline to the opposite side of the spinal cord or brain stem) in each somatosensory pathway below the level of the thalamus. All somatosensory pathways include a thalamic nucleus.
Where do sensory neurons in the posterior column Decussate?
The fibres of this decussation are called the internal arcuate fibres and are found at the superior aspect of the closed medulla superior to the motor decussation. It is part of the second neuron in the posterior column–medial lemniscus pathway.
Where do nerves Decussate?
In neuroanatomy, the term chiasma is reserved for crossing of- or within nerves such as in the optic chiasm. In botanical leaf taxology, the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem when viewed from above).
Where is the sensory decussation?
The sensory decussation or decussation of the lemniscus is a decussation or cross over of axons from the gracile nucleus and cuneate nucleus. The fibres of this decussation are called the internal arcuate fibres and are found at the superior aspect of the closed medulla superior to the motor decussation.
Where do cranial nerves cross over?
It is important to remember that cranial nerves never cross (except for one exception, the 4th CN) and clinical findings are always on the same side as the cranial nerve involved.
At what level of the brain stem does the dorsal column tract Decussate?
The medial lemniscus is the rostral continuation of the dorsal column. Axons from second-order neurons decussate at the level of the medulla and travel up the brainstem as the medial lemniscus on the contralateral (opposite) side.
Where do nociceptive neurons Decussate?
The first-order nociceptive neurons (in the DRG) make synaptic connections in Rexed layer I neurons (marginal zone). Axons from layer I neurons decussate in the anterior white commissure, at approximately the same level they enter the cord, and ascend in the contralateral anterolateral quadrant.
Do cranial nerves Decussate?
The cranial nerves do not decussate generally with exceptions being CN2, CN4, CN7 and CN12. That means if a lesion affects Cranial Nerve 1, 5, 8, 9 and 11 or the respective nucleus there is either sensation loss or atrophy of the muscle (dependent on what the nerve does) of the ipsilateral side.
Do any cranial nerves Decussate?
Where does the spinothalamic tract Decussate?
We can contrast the spinothalamic tract with the dorsal column/medial lemniscus pathway. The former crosses/decussates at the level of the spinal nerve, where as the latter crosses at the level of the medulla.
Where does the Spinomesencephalic tract Decussate?
8. Course of the spinomesencephalic tract in a macaque monkey. The cells of origin of the tract are concentrated in laminae I and V. The axons decussate in the ventral white commissure and ascend to the midbrain in the lateral funiculus.
Where do the cranial nerves Decussate?
The nerve decussates at the superior medullary velum after leaving the brainstem, which causes cranial nerve nuclei deficits to appear as loss of function of the contralateral superior oblique muscle.