Rubrospinal tract mediates flexor of the upper arm.
Here is a way to remember these two postures and never forget again.
Decerebrate has more “E” and more “R”.
- Extended upper limbs
- Rubrospinal tract transected (Red nucleus is above the level of lesion, i.e. below midbrain level)
Decorticate has “COR”.
- Upper limbs are brought towards CORE (i.e. flexed)
- Loss of CORTICAL inhibition of red nucleus (rubro-spinal tract), i.e. tonic discharge from red nucleus.
Lower limb in extended and plantar flexed in both the cases.