Diseases
If the rear strand tract is damaged, the so-called rear strand ataxia occurs. Here, movements are uncoordinated and the gait pattern is very uncertain. Patients have a marked tendency to fall because information about the position of joints and muscles in space is no longer adequately passed on and the extent of movements can no longer be correctly estimated by the brain.
The unconscious “counter-steering” of the body can therefore no longer function properly. Because the fibers that conduct this information only cross over to the opposite side late (in the brain stem), patients have a tendency to fall to the side where the damage is also in the spinal cord (ipsilateral). In addition, they lack the sense of vibration (so-called pall anaesthesia) and the ability to recognize objects by touching them with the hands when the eyes are closed (stereo diagnostics).
The ability to perceive two simultaneous stimuli on the skin as being located in different places (two-point discrimination) also decreases or is missing. Causes of damage to the rear tract may be
- Last (4.) stage of syphilis (Tabes dorsalis)
- Funicular myelosis (destruction of nerve sheaths in vitamin B 12 deficiency)
- Spinal cord tumors
- Closure of the posterior spinal cord arteries
