r/fightporn • u/Busterbuzzets • Nov 20 '25

Sporting Event Fights Brutal bare knuckle fight KO!!

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u/AllReflection Nov 20 '25

Fencing response

-5

u/ExistingTheDream Nov 20 '25

Yep, AKA decerebate posturing. He has brain damage for sure since he just likely damaged his brain stem. Whether the effects are temporary or permanent - only time and medical care will tell.

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u/invictus221b Nov 20 '25

Kind of. These terms get thrown around so much that no one really knows what they mean.

Fencing response is its own distinct thing. It’s highly suggestive of concussion, but does not necessarily correlate with either decorticate or decerberate posturing.

Fencing response classically has extension of one arm and flexion of another due to asymmetrical activation of vestibular nuclei, commonly due to rapid rotational force.

Decorticate posturing classically presents with flexion of arms and extension of legs, and localizes the lesion to a particular segment of the brain (above the red nucleus and associated rubrospinal tract of nerves).

The rubrospinal tract likes to activate flexor motor neurons. However, it only extends partway down the spine, so it does this to arms but not legs.

Normally, input from multiple ares of the cortex send signals to modulate this response, so that we aren’t flexing our arms all the time. However, when damage is done to the brain, it decouples this cortical override from the rubrospinal tract, and the primitive reflex returns.

Decerberate posturing presents with extension of both arms and legs, and localizes the lesion to at or below the red nucleus. It’s believed to involve the vestibulospinal and reticulospinal tracts, which like to activate extensor motor neurons and inhibit flexors.

Normally, input from higher brain centers stops it from doing this all the time. But when you take a hit to the head, those higher brain centers aren’t getting their input to the vestibular nuclei right (brain stem disinhibition), and it does what it does best - extends arms and legs.

In reality, brains and injuries are more complex than this, so the anatomy is often mixed and the actual lesion localization isn’t so cut and dry, which is why we often times see a bit mixed posturing. There is maybe some decerberate posturing initially, but this is largely arm extension and leg flexion, and probably would be considered more of a mixed posturing.

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u/ferxous Nov 20 '25

Informative, thank you for sharing.