Death of a section of heart muscle when its blood supply is cut off, usually by a blood clot in a coronary artery narrowed by atherosclerosis. Hypertension, diabetes mellitus, high cholesterol, cigarette smoking, and coronary heart disease increase the risk. Symptoms include severe chest pain, often radiating to the left arm, and shortness of breath. Up to 20percnt of victims die before reaching the hospital. Diagnosis is done by electrocardiography and by analysis for enzymes in the blood. Treatment aims to limit the area of tissue death (infarct) and prevent and treat complications. Thrombolytic (clot-dissolving) drugs may be administered. Beta-blockers alleviate pain and slow the heart rate. Angioplasty or coronary bypass restores blood flow to heart muscle. Follow-up may include drugs, exercise programs, and counseling on diet and lifestyle changes.
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A strike is an attack with an inanimate object, such as a weapon, or with a part of the human body intended to cause an effect upon an opponent or to simply cause harm to an opponent. There a many different varieties of strikes. An attack with the hand closed into a fist is called a punch; an attack with the leg or foot is referred to as a kick; and an attack with the head is called a headbutt. There are also other variations employed in martial arts and combat sports.
In general, if a strike is applied to certain pressure points, the resulting percussive shock can disrupt the nervous system causing shock and sometimes loss of consciousness. The bottom ridge of the palm is a surprisingly solid striking surface, and can do just as much damage as a closed fist when utilized properly (some studies have shown that a palm strike actually can produce more energy then a a punch in most cases), with far less risk of injury to the striker's own hand.
The palm strike is useful as it is thrown in a more relaxed manner than a clenched fist. This is because clenching the fist shortens the extensor muscles of the wrist which counter the action of flexor muscles of the wrist used in punching. Many martial arts teach to keep the fist clench relaxed until impact in order to maximize the speed of the punch.
Targets are numerous and some examples include the nose, jaw ,ears, back of the head, the groin, the kidneys and abdominal cavity. Some combat sports, such as Pancrase, have forbidden strikes using the clenched fist but permitted strikes using the palm.
A strike using the part of the hand opposite the thumb (from the little finger to the wrist), familiar to many people as a karate chop, Shuto or Tegatana. This refers to strikes performed with the side of the knuckle of the small finger. Suitable targets for the knife hand strike include the mastoid muscles of the neck, the jugular, the throat, the collar bones, the 3rd vertebra (key stone of the spinal column), the upper arm, the wrist (knife hand block), the elbow (outside knife hand block), and the knee cap (leg throw). In many Japanese and Chinese martial arts systems, the knife hand is used to block as well as to strike.
By tucking the thumb into the palm, a striking surface called the ridge-hand, or reverse knife-hand is formed, extending a few inches along the inside of the hand below the first knuckle of the first finger. Ridge-hand strikes commonly are delivered with a hooking motion, or with a straight arm swing
Suitable targets include the mastoid muscles of the neck, the jugular, throat, nose, jaw, and the groin.
Delivered just as with a punch except that the hand is held open like with a knife hand. Referred to as a Biu Sao in Wing Chun, the intended striking area are the tips of the fingers.The ideal targets are the eyes and throat. Obviously, use of this technique is generally unsuitable against most other targets due to the high probability that one might break their fingers.
This strike will not damage the bones of the hands as there is no compression of the knuckles or metacarpals, and there is no leverage to bend the wrist.
The hammer fist strikes cricket ball sized areas on the body, hence is particularly effective for striking the Occiput, the temples, the nose, the mandible, the wrist (for blocking punches), the sternum, and the ear (although a cupped hand is more effective). The hammerfist is sometimes used during "ground-and-pound" striking in mixed martial arts to avoid damaging the bones of the hand.
Strikes in Asian martial arts and Western boxing have many of the same principles in common. These principles apply to strikes with most parts of the human body. These principles are typically learned by martial artists through multiple repetitions under the supervision of a qualified instructor. Many martial arts and texts include these principles, such as karate and Jeet Kun Do. This is only a partial list.
The wrist must also be kept in proper alignment during a fist strike. If the wrist bends on impact, it can easily be sprained, dislocated or broken. Boxers tape their wrists to reduce wrist flex.
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