Why does brainstem damage cause decerebrate posturing?

[Bluebell.]

I thought brainstem damage only meant damage in the vital centers and arousal.

[Esme12, ASN, BSN, RN]

What does the brain stem do? If you have a disconnect between the two, brain stem and spinal chord, what happens?

[Bluebell.]

What does the brain stem do? If you have a disconnect between the two, brain stem and spinal chord, what happens?

I'm guessing a disconnect from the brain completely means no movement is possible.

[Esme12, ASN, BSN, RN]

but there are spinal reflexes....the actual mechanism is poorly understood...Decerebrate rigidity is caused by extensive brainstem (medulla and pons) damage. There is head extension with body arched; the arms are extended, adducted. and pronated; the legs are extended with plantar flexion of the feet. Motor impulses are transmilted to the spinal cord from the motor cortex via the pyramidal and extrapyramidal tracts. Impulses from the motor cortex are carried directly to the spinal cord via the pyramidal tract. (The pyramidal tract is also called the corticospinal tract). Impulses are also carried through the basal ganglia, cerebellum and brainsterm nuclei to the spinal cord. This latter pathway is referred to as the extrapyramidal system. Damage/Lesions involving areas of the extrapyramidal system are characterized by movement disturbances

[Bluebell.]

but there are spinal reflexes....the actual mechanism is poorly understood...Decerebrate rigidity is caused by extensive brainstem (medulla and pons) damage. There is head extension with body arched; the arms are extended, adducted. and pronated; the legs are extended with plantar flexion of the feet. Motor impulses are transmilted to the spinal cord from the motor cortex via the pyramidal and extrapyramidal tracts. Impulses from the motor cortex are carried directly to the spinal cord via the pyramidal tract. (The pyramidal tract is also called the corticospinal tract). Impulses are also carried through the basal ganglia, cerebellum and brainsterm nuclei to the spinal cord. This latter pathway is referred to as the extrapyramidal system. Damage/Lesions involving areas of the extrapyramidal system are characterized by movement disturbances

Thanks for the info!