A shepherd's crook is a long and sturdy stick with a hook at one end, often with the point flared outwards, used by a shepherd to manage and sometimes catch sheep. In addition, the crook may aid in defending against attack by predators. When traversing rough terrain, a crook is an aid to balance. Shepherds may also use the long implement to part thick undergrowth (for example at the edge of a drovers' road) when searching for lost sheep or potential predators.
The innovation of a hook facilitates the recovery of fallen animals by ensnaring them by the neck or leg. For this reason, the crook has been used as a religious symbol of care (particularly in difficult circumstances), including the Christian bishop's crosier. [1]
In medicine, the term shepherd’s crook is used to describe a right coronary artery that follows an unusually high and winding route. This variant, which has a prevalence of about 5%, [2] imposes technical problems in angioplasty procedures. [3]
The letter lamed originated as a representation of a shepherd's crook or goad, from which the Latin letter L has evolved.[ citation needed ]
Ancient Greeks called it κορύνη, λαγωβόλον and καλαῦροψ and in their art the crook is often seen in the hands of Pan and also is the usual attribute of Thalia, as the Muse of pastoral poetry. [4]
The shepherd's crook and the flail (an agricultural tool) are insignia of pharaonic authority.[ citation needed ]
Angioplasty, also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis. A deflated balloon attached to a catheter is passed over a guide-wire into the narrowed vessel and then inflated to a fixed size. The balloon forces expansion of the blood vessel and the surrounding muscular wall, allowing an improved blood flow. A stent may be inserted at the time of ballooning to ensure the vessel remains open, and the balloon is then deflated and withdrawn. Angioplasty has come to include all manner of vascular interventions that are typically performed percutaneously.
Arteriosclerosis literally means "hardening of the arteries" and is an umbrella term for a vascular disorder characterized by abnormal thickening, hardening, and loss of elasticity of the walls of arteries; this process gradually restricts the blood flow to one's organs and tissues and can lead to severe health risks brought on by atherosclerosis, which is a specific form of arteriosclerosis caused by the buildup of fatty plaques, cholesterol, and some other substances in and on the artery walls.
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performed by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy.
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional (treatment) purposes.
Restenosis is the recurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage and subsequently become renarrowed. This is usually restenosis of an artery, or other blood vessel, or possibly a vessel within an organ.
Stenosis is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture.
An atheroma, or atheromatous plaque, is an abnormal accumulation of material in the inner layer of an arterial wall.
Intravascular ultrasound (IVUS) or intravascular echocardiography is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter. The proximal end of the catheter is attached to computerized ultrasound equipment. It allows the application of ultrasound technology, such as piezoelectric transducer or CMUT, to see from inside blood vessels out through the surrounding blood column, visualizing the endothelium of blood vessels.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
In medical and surgical therapy, revascularization is the restoration of perfusion to a body part or organ that has had ischemia. It is typically accomplished by surgical means. Vascular bypass and angioplasty are the two primary means of revascularization.
A wolf in sheep's clothing is an idiom from Jesus's Sermon on the Mount as narrated in the Gospel of Matthew. It warns against individuals who play a duplicitous role. The gospel regards such individuals as dangerous.
Percutaneous coronary intervention (PCI) is a minimally invasive non-surgical procedure used to treat narrowing of the coronary arteries of the heart found in coronary artery disease. The procedure is used to place and deploy coronary stents, a permanent wire-meshed tube, to open narrowed coronary arteries. PCI is considered 'non-surgical' as it uses a small hole in a peripheral artery (leg/arm) to gain access to the arterial system, an equivalent surgical procedure would involve the opening of the chest wall to gain access to the heart area. The term 'coronary angioplasty with stent' is synonymous with PCI. The procedure visualises the blood vessels via fluoroscopic imaging and contrast dyes. PCI is performed by an interventional cardiologists in a catheterization laboratory setting.
A drug-eluting stent (DES) is a thin tube that is used to treat narrowed arteries in medical procedures. It releases drugs to prevent the growth of scar tissue and reduce the risk of stent restenosis, which is the narrowing of the stented area of an artery after treatment. A drug-eluting stent is different from other types of stents because it has a coating that delivers medication directly to the arterial wall. A DES is often made of metal alloys and can be inserted into blocked or narrowed arteries through a catheter placed in a peripheral artery, such as in the arm or leg. DES is fully integrated with a catheter delivery system and is viewed as one integrated medical device.
Coronary artery anomalies are variations of the coronary circulation, affecting <1% of the general population. Symptoms include chest pain, shortness of breath and syncope, although cardiac arrest may be the first clinical presentation. Several varieties are identified, with a different potential to cause sudden cardiac death.
The history of invasive and interventional cardiology is complex, with multiple groups working independently on similar technologies. Invasive and interventional cardiology is currently closely associated with cardiologists, though the development and most of its early research and procedures were performed by diagnostic and interventional radiologists.
"The Shepherd" is a poem from William Blake's Songs of Innocence (1789). This collection of songs was published individually four times before it was combined with the Songs of Experience for 12 editions which created the joint collection Songs of Innocence and of Experience (1794). Blake produced all of the illuminated printings himself beginning in 1789. Each publication of the songs has the plates in a different order, and sixteen other plates were published posthumously.
Coronary artery aneurysm is an abnormal dilatation of part of the coronary artery. This rare disorder occurs in about 0.3–4.9% of patients who undergo coronary angiography.
A shepherd or sheepherder is a person who tends, herds, feeds, or guards flocks of sheep. Shepherd derives from Old English sceaphierde. Shepherding is one of the world's oldest occupations, it exists in all parts of the globe, and it is an important part of pastoralist animal husbandry.
Reperfusion therapy is a medical treatment to restore blood flow, either through or around, blocked arteries, typically after a heart attack. Reperfusion therapy includes drugs and surgery. The drugs are thrombolytics and fibrinolytics used in a process called thrombolysis. Surgeries performed may be minimally-invasive endovascular procedures such as a percutaneous coronary intervention (PCI), which involves coronary angioplasty. The angioplasty uses the insertion of a balloon and/or stents to open up the artery. Other surgeries performed are the more invasive bypass surgeries that graft arteries around blockages.
Cardiac magnetic resonance imaging perfusion, also known as stress CMR perfusion, is a clinical magnetic resonance imaging test performed on patients with known or suspected coronary artery disease to determine if there are perfusion defects in the myocardium of the left ventricle that are caused by narrowing of one or more of the coronary arteries.
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The dictionary definition of shepherd's crook at Wiktionary