Blood squirt (blood spurt, blood spray, blood gush, or blood jet) is the effect when an artery, a blood vessel in the human body (or other organism's body), is cut. Blood pressure causes the blood to bleed out at a rapid, intermittent rate, in a spray, squirt, gush or jet, coinciding with the beating of the heart, rather than the slower, but steady flow of venous bleeding. Also known as arterial bleeding, arterial spurting, or arterial gushing, the amount of blood loss can be copious, occur very rapidly, and can lead to death.
In cut carotid arteries with 100 mL of blood through the heart at each beat (at 65 beats a minute), a completely severed artery will spurt blood for about 30 seconds and the blood will not spurt much higher than the human head. If the artery is just nicked, on the other hand, the blood will spurt longer but will be coming out under pressure and spraying much further.
To prevent hand ischemia, there is a "squirt test" that involves squirting blood from the radial artery, which is used in intraoperative assessment of collateral arm blood flow before radial artery harvest.
Chhinnamasta, a self-decapitated Hindu goddess, is depicted holding her head with three jets of blood spurting out of her bleeding neck, which are drunk by her severed head and two attendants. Saint Miliau, a Christian martyr killed c. 6th century AD, is sometimes represented holding his severed head, as in the retable of the Passion of the Christ at Lampaul-Guimiliau, where blood gushes from his neck.
Insects and animals 
Some animals deliberately autohaemorrhage or spurt/squirt blood as a defense mechanism. Armored crickets, which are native to Namibia, South Africa, and Botswana, have a unique way of driving away predators: they spew vomit and spurt hemolymph (the mollusk and arthropod version of blood) from under their legs and through slits in their exoskeleton. Katydids do it too; in fact, in Germany the species has acquired the nickname "blutspritzer", or "blood squirter". The regal horned lizard, too, uses the blood-spewing tactic, shooting the substance from a pocket near its eyes.
Popular culture 
Squirting blood is used as a special/visual effect in theater, film (mostly horror – particularly slasher – and action), television series (mostly horror and drama), cartoons, anime, comic books, and video games.
Cormac McCarthy's 1985 novel Blood Meridian, Or the Evening Redness in the West includes a scene in which one of the two Jacksons decapitates the other by a campfire, leading to a graphically described blood spurt.
The 1991 film Star Trek VI: The Undiscovered Country has a scene where a Klingon gets shot (phasered) in zero gravity. The blood that spurts out of the Klingon's wounds was created using computer generated imagery (CGI); the animators had to make sure that the blood floated in a convincing manner while still looking interesting and not too gory. The effects artist looked at NASA footage of floating water globules to match the physics of the blood particles.
Video games can use a particle system to create blood squirt/splat/pool effects. The blood-gushing special effects in Mortal Kombat (1992) engendered controversy which only served to boost its popularity.
The television series Dexter is centered around the life of a blood-spatter analysis specialist Dexter Morgan working in the Miami Police Department (who is also a serial killer).
See also 
- Bloodstain pattern analysis, in forensic science
- Bodily mutilation in film#Blood
- Spurt of Blood, a 1925 French surreal play
- Theatrical blood
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