Nerve05/disorders of the spinal cord and optic pathway/level of right-left crossing
Various spinal pathways differ according to the level at which the right-left midline is crossed.
The sensation of temperature and pain crosses at the spinal nerve level. [The spinal nerve through which the afferent signals travel differs according to the level of the skin; this height is called the dermatome.] In contrast, the deep sensation, touch/pressure sensation, descending pathway crosses at the medulla oblongata level.
So, for the right arm, the sensation of temperature and pain travels through the left half of the spinal cord, whereas the deep sensation, touch/pressure sensation travels through the right half of the spinal cord. Also, the efferent motor signals to the right arm descend through the right half of the spinal cord (as shown in the illustration).
Challenge Quiz
The sensation of temperature and pain crosses the right-left midline at the medulla oblongata spinal nerve level .
The deep sensation and touch/pressure sensation cross right-left midline at the medulla oblongata spinal nerve level .
The descending pathway for voluntary movement crosses the right-left midline at the medulla oblongata spinal nerve level .
The sensation of temperature and pain of the right arm travel through the right half left half of the spinal cord.
The deep sensation (such as from joints and muscles), touch/pressure sensation of the right arm, travels through the right half left half of the spinal cord.
The efferent motor signals to the right arm descend through the right half left half of the spinal cord.
The sensation of temperature and pain of the left arm travel through the right half left half of the spinal cord.
The deep sensation (such as from joints and muscles), touch/pressure sensation, of the left arm travels through the right half left half of the spinal cord.
The efferent motor signals to the left arm descend through the right half left half of the spinal cord.