Medical What Are the Effects and Causes of the Biceps Reflex?

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The discussion centers on the reflex actions related to pressing the lateral cutaneous nerve near the biceps brachii tendon and the resulting physical responses, such as leg buckling and body bending. Key points include the clarification that the biceps tendon is located medially, not laterally, and that the biceps reflex tests the integrity of the C5 spinal nerve, while the triceps reflex assesses the C7 nerve. It is noted that mild pain in the arm typically should not cause leg buckling, suggesting that if such a reaction occurs, it may warrant medical consultation. The phenomenon may be attributed to body positioning and balance rather than a direct neurological connection between the arm and leg. The discussion emphasizes the importance of understanding reflexes and the body's automatic responses to maintain balance.
Nikolaj FS
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Im curious about this reflex.

What does it affect?

#1 - Does it causes the hand to open/close - if yes, why?
#2 - Does will it flex either the tricep or the bicep?

I've noted by pressing the the latereal cutaneous nerve with a thumb, which is close to the biceps brachii tendon the sameside leg buckles, the back bends forward along with the head.

Can anyone explain this phenomen? Is it due to the crossed extensor reflex or something else? Reestablishing balance?

Hope you can help.
 
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If pressing on your arm causes your knees to buckle, go see a doctor.

The biceps tendon is more toward the medial side of the arm, not the lateral side, so should have nothing to do with the lateral cutaneous nerve of the forearm. As the name of the reflex implies, it causes contraction of the biceps brachii muscle. You're testing integrity of the C5 spinal nerve with that reflex.

The triceps reflex is separate and tests primarily C7 spinal nerve integrity.
 
So you say that by inflicting pain into the nervous system, you should not be able to buckle the legs?
 
I would say by inflicting mild pain in the arm, you should not be buckling your legs (we've all bumped our ulnar nerve..."the funny bone" and our knees don't buckle from it).

If you were managing to inflict great amounts of pain upon yourself and didn't quit before getting to that point, I think you should consider consulting a psychiatrist.
 
No acting - i get the same effect on 9 out of 10 people, even on my self. Any reflexes could explain this effect, or just auto balancing the body ?
 
Seriously, there is no connection in what you're describing in the arm to what you're describing in the leg. It could have something to do with simply the position they put the person in in the first place, pulling them slightly off balance with the initial set up, so one more tug on the arm causes them to lose their balance and correct. That light little tap on the arm is just distraction.
 
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