Explain how a carotid choke works.

[danno]

based on their anatomical proximity to the vascular system, it is usually going to be impossible to stimulate one without the other

i don't yet see any reason to think that this is the reason people are passing out when you strangle them though (pressure on the vagus nerve). in the literature, they seem to hypothesise that it may cause death, but don't mention anything about the instant fainting and instant recovery we observe in martial arts. and even the death thing is controversial.

i used to suffer infrequent SVTs myself until recently when i underwent catheter ablation. i no longer get them. so i know what it's like to have unusual heart beats - both SVTs and bradycardia. skipped beats too, and i had basically all of this one after the other while recovering from surgery. these sensations feel nothing like getting strangled.

EDIT - wrong, they do mention fainting with carotid sinus hypersensitivity. i'm starting to get interested. i'd like to compare the symptoms of CSH to this:

http://youtu.be/qTPOrRwP0Ow

i don't trust their conclusions, just posting it as an example of someone getting put to sleep.

i'd like to know how much the blood pressure changes in the brain itself during the choke.

[DCS]

i asked about pressing on the vagus nerve to knock someone out. you posted stuff about carotid sinus pressure and said that yes, you can knock someone out by pressing on nerves. now you say that you weren't actually talking about nerves.

Let's see.

the carotid sinus is a localized dilation of the internal carotid artery at its origin, the common carotid artery bifurcation. A synonym for the carotid sinus is the carotid bulb.

The carotid sinus contains numerous baroreceptors, which function as a "sampling area" for many homeostatic mechanisms for maintaining blood pressure. The carotid sinus baroreceptors are innervated by the sinus nerve of Hering, which is a branch of cranial nerve IX (glossopharyngeal nerve).

What I' saying is carotid sinus is not a nerve, but there are nerves there.



Pressure in this area, as in choking, affects to pressure receptors, nerves, arteries and veins at the same time.

So yes, my answer (So, basically, you can) was inexact because to put pressure in the nerves "only" you'll need a sharp knife, very good vision and better pulse.

i'm not an anatomist and my girlfriend is asleep. help me out here.

You're not thinnking about choking her, is it?

[danno]

that's great DCS, thanks.

i'd really like to see how different the blood pressure is in the brain compared to the rest of the body during a choke. if the BP in the body drops because of carotid sinus pressure, yet the BP in the brain is much higher, then the reason you pass out is probably NOT because of the bradycardia.

[DCS]

If you are restricting blood input and output at the same time, blood pressure inside the brain should remain constant... around zero variation from what was before the choke.

Better said, if you put a tourniquet in your arm, what would be the BP in the distal side?

[danno]

yeah, that's what i used to think. but get someone to choke you just a bit, and focus on how your face feels - seems like it's going to pop, right?

consider that arteries are thicker and under higher pressure than the veins, and the veins are closer to the surface, so may be constricted easier(this part might not actually matter). blood can enter the brain, but it can't escape so well. blood pressure would rise.

[bob63]

the damage to blood vessels in the face and eyes during strangulation is known as petechiae.

the wiki' forensic definition states;

Petechiae on the face and conjunctiva (eyes) can be a sign of a death by asphyxiation. Petechiae are thought to result from an increase of pressure in the veins of the head* and hypoxic damage to endothelia of blood vessels.[3]
Petechiae can be used by police investigators in determining is strangulation has been part of an attack. The documentation of the presence of petechiae on a victim can help police investigators prove the case.[4] Petechiae resulting from strangulation can be relatively tiny and light in color to very bright and pronounced. Petechiae may be seen on the face, in the whites of the eyes or on the inside of the eyelids"

(* my emphasis not theirs)

IMO this would add weight to the theory of blood being stopped from leaving the head by constriction of the veins in the neck, rather than blood to the head by constriction of the arteries.

Until it was specifically banned in the late eighties I used to technique effectively by placing subject's neck in crook of my left arm from behind, palm down. I would then turn the hand to tense the bicep into the left side of the neck between the windpipe and muscle bunch below the ear. Person would pass out within seconds consistently, no impact to nerves and no restriction on breathing.




video shows it used live, watch in front of the banner over the railings, male put to sleep is up and about shortly after, male punched out by other doorman is out a lot longer (but they do kindly drag him out of the way of the taxis).

[DCS]

In that case (blood being stopped from leaving the head) we would have cerebrospinal fluid (csf) escaping towards the spinal canal to compensate intracranial pressure.

The principle constituents within the skull are brain (80%), blood (12%) and CSF (8%). The total volume is 1600ml. The skull is thus a rigid fluid filled box. If the volume of the contents of a rigid fluid-filled container increase, the pressure inside will rise considerably unless some fluid is able to escape. So it is with the skull and brain within it.

If the brain enlarges, some blood or CSF must escape to avoid a rise in pressure. If this should fail, or be unable to occur there will be a rapid increase in ICP from the normal range (5-13 mmHg). If there is an increase in the volume of either the brain or blood the normal initial response is a reduction in CSF volume within the skull. CSF is forced out into the spinal sac. Thus the pressure within the skull, ICP, is initially maintained*. If the pathological process progresses with further increase in volume, venous blood and more CSF is forced out of the skull.

Ultimately this process becomes exhausted, when the venous sinuses are flattened and there is little or no CSF remaining in the head. Any further increase in brain volume then causes a rapid increase in ICP. This chain of events is represented by the sequence in Fig 1a and 1b.
http://www.nda.ox.ac.uk/wfsa/html/u08/u08b_t1a.gif
http://www.nda.ox.ac.uk/wfsa/html/u08/u08b_t1b.gif

http://www.nda.ox.ac.uk/wfsa/html/u08/u08_013.htm

Brain shutting off would happen after almost all csf has gone.

High intracranial pressure symptoms are:

Signs and symptoms
In general, symptoms and signs that suggest a rise in ICP including headache, vomiting without nausea, ocular palsies, altered level of consciousness, back pain and papilledema. If papilledema is protracted, it may lead to visual disturbances, optic atrophy, and eventually blindness.
In addition to the above, if mass effect is present with resulting displacement of brain tissue, additional signs may include pupillary dilatation, abducens (CrN VI) palsies, and the Cushing's triad. Cushing's triad involves an increased systolic blood pressure, a widened pulse pressure, bradycardia, and an abnormal respiratory pattern
http://en.wikipedia.org/wiki/Intracr...s_and_symptoms

*bold mine

[bob63]

Although it pans away from the video male was rendered unconscious in about 8 seconds. Would that be enough time for the build up of pressure to displace csf or just starve it of fresh oxygen by way of "traffic jam" principle eluded to?

[W. Rabbit]

i don't yet see any reason to think that this is the reason people are passing out when you strangle them though (pressure on the vagus nerve). in the literature, they seem to hypothesise that it may cause death, but don't mention anything about the instant fainting and instant recovery we observe in martial arts. and even the death thing is controversial.

Feinting (syncope) from choking (from either external constriction or internal to your body, like asthmatic swelling) and recovery go hand in hand with the vasovagal response. That's straight from Putin's book on judo as well as many of the sources on strangulation (not death by strangulation, just strangulation).

But JUST because the vagus is involved doesn't mean it's a "nervous response" only. It's a systemic response involving both circulatory and CNS components.

The vagus is a nerve directly connected to the arteries in the neck, because it is a pressure sensor designed to shut the heart's pumping down significantly if overpressure occurs (which is exactly the situation during a choke).

Pressuring the neck (including arteries) causes a false reading in the vagus, just like if you were to hold a flame near a thermostat or a barometer near a fan. The results are dramatic and swift.

This was my point a few posts ago, it doesn't make sense to talk about ONLY the circulatory system or ONLY the nervous system in isolation. What's occuring is a biofeedback mechanism involving both, simultaneously. So the response is a holistic one, not just one organ system doing something.

In fact, the correct medical term for the vasovagal response is "neurocardiogenic syncope", in other words, feinting from response to both cardiovascular and nervous system changes.

Also probably why Putin's book mentions 5 or 6 medical "causes" of feinting from shime waza techniques, instead of 1. There is no single answer, the real answer is complicated and can involve many different components of the body (nerves, arteries, BP, oxygen levels, blood chemistry, probably even hormone levels).

[DCS]

In response to bilateral jugular compression, the sac again distends as indicated by the column that widens, moves caudally and fills the lumbosacral nerve root sleeves. The response reaches maximum in five to 10 seconds. With release of jugular compression, the column regains in a few seconds its pre-compression appearance.
http://www.ncbi.nlm.nih.gov/pmc/arti...00208-0044.pdf

We have between 5-10 seconds to fill the spinal canal with cfs. After this the intracranial pressure will raise.

I think the intercranial pressure will not raise very fast because pressure in the carotid will reduce the amount of blood reaching the brain. Constricting the jugulars only, without affecting the carotids, seems almost impossible.