Models, Anatomic: Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.Cadaver: A dead body, usually a human body.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Pelvic Pain: Pain in the pelvic region of genital and non-genital origin and of organic or psychogenic etiology. Frequent causes of pain are distension or contraction of hollow viscera, rapid stretching of the capsule of a solid organ, chemical irritation, tissue ischemia, and neuritis secondary to inflammatory, neoplastic, or fibrotic processes in adjacent organs. (Kase, Weingold & Gershenson: Principles and Practice of Clinical Gynecology, 2d ed, pp479-508)Anatomic Landmarks: Reference points located by visual inspection, palpation, or computer assistance, that are useful in localizing structures on or within the human body.Imaging, Three-Dimensional: The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.Pathology, Surgical: A field of anatomical pathology in which living tissue is surgically removed for the purpose of diagnosis and treatment.Dissection: The separation and isolation of tissues for surgical purposes, or for the analysis or study of their structures.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Chromosome Inversion: An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Anatomy: A branch of biology dealing with the structure of organisms.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Image Interpretation, Computer-Assisted: Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.Paranasal Sinuses: Air-filled spaces located within the bones around the NASAL CAVITY. They are extensions of the nasal cavity and lined by the ciliated NASAL MUCOSA. Each sinus is named for the cranial bone in which it is located, such as the ETHMOID SINUS; the FRONTAL SINUS; the MAXILLARY SINUS; and the SPHENOID SINUS.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Image Enhancement: Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Temporal Bone: Either of a pair of compound bones forming the lateral (left and right) surfaces and base of the skull which contains the organs of hearing. It is a large bone formed by the fusion of parts: the squamous (the flattened anterior-superior part), the tympanic (the curved anterior-inferior part), the mastoid (the irregular posterior portion), and the petrous (the part at the base of the skull).Pelvis: The space or compartment surrounded by the pelvic girdle (bony pelvis). It is subdivided into the greater pelvis and LESSER PELVIS. The pelvic girdle is formed by the PELVIC BONES and SACRUM.Catheter Ablation: Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.Surgery, Computer-Assisted: Surgical procedures conducted with the aid of computers. This is most frequently used in orthopedic and laparoscopic surgery for implant placement and instrument guidance. Image-guided surgery interactively combines prior CT scans or MRI images with real-time video.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Radiopharmaceuticals: Compounds that are used in medicine as sources of radiation for radiotherapy and for diagnostic purposes. They have numerous uses in research and industry. (Martindale, The Extra Pharmacopoeia, 30th ed, p1161)Factor XII: Stable blood coagulation factor activated by contact with the subendothelial surface of an injured vessel. Along with prekallikrein, it serves as the contact factor that initiates the intrinsic pathway of blood coagulation. Kallikrein activates factor XII to XIIa. Deficiency of factor XII, also called the Hageman trait, leads to increased incidence of thromboembolic disease. Mutations in the gene for factor XII that appear to increase factor XII amidolytic activity are associated with HEREDITARY ANGIOEDEMA TYPE III.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Observer Variation: The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).Subtraction Technique: Combination or superimposition of two images for demonstrating differences between them (e.g., radiograph with contrast vs. one without, radionuclide images using different radionuclides, radiograph vs. radionuclide image) and in the preparation of audiovisual materials (e.g., offsetting identical images, coloring of vessels in angiograms).Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Capparis: A plant genus of the family CAPPARACEAE that contains mabinlin, a sweet protein.Angiography: Radiography of blood vessels after injection of a contrast medium.Positron-Emission Tomography: An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.Orbit: Bony cavity that holds the eyeball and its associated tissues and appendages.Bacteriology: The study of the structure, growth, function, genetics, and reproduction of bacteria, and BACTERIAL INFECTIONS.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Magnetic Resonance Angiography: Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.Vascular Malformations: A spectrum of congenital, inherited, or acquired abnormalities in BLOOD VESSELS that can adversely affect the normal blood flow in ARTERIES or VEINS. Most are congenital defects such as abnormal communications between blood vessels (fistula), shunting of arterial blood directly into veins bypassing the CAPILLARIES (arteriovenous malformations), formation of large dilated blood blood-filled vessels (cavernous angioma), and swollen capillaries (capillary telangiectases). In rare cases, vascular malformations can result from trauma or diseases.Fluoroscopy: Production of an image when x-rays strike a fluorescent screen.Tomography, Emission-Computed, Single-Photon: A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.Health Care Costs: The actual costs of providing services related to the delivery of health care, including the costs of procedures, therapies, and medications. It is differentiated from HEALTH EXPENDITURES, which refers to the amount of money paid for the services, and from fees, which refers to the amount charged, regardless of cost.Contrast Media: Substances used to allow enhanced visualization of tissues.Tomography, Emission-Computed: Tomography using radioactive emissions from injected RADIONUCLIDES and computer ALGORITHMS to reconstruct an image.Aortography: Radiographic visualization of the aorta and its branches by injection of contrast media, using percutaneous puncture or catheterization procedures.Suture Anchors: Implants used in arthroscopic surgery and other orthopedic procedures to attach soft tissue to bone. One end of a suture is tied to soft tissue and the other end to the implant. The anchors are made of a variety of materials including titanium, stainless steel, or absorbable polymers.Finger Phalanges: Bones that make up the SKELETON of the FINGERS, consisting of two for the THUMB, and three for each of the other fingers.Cranial Fossa, Middle: The compartment containing the anterior extremities and half the inferior surface of the temporal lobes (TEMPORAL LOBE) of the cerebral hemispheres. Lying posterior and inferior to the anterior cranial fossa (CRANIAL FOSSA, ANTERIOR), it is formed by part of the TEMPORAL BONE and SPHENOID BONE. It is separated from the posterior cranial fossa (CRANIAL FOSSA, POSTERIOR) by crests formed by the superior borders of the petrous parts of the temporal bones.AxisLigaments, Articular: Fibrous cords of CONNECTIVE TISSUE that attach bones to each other and hold together the many types of joints in the body. Articular ligaments are strong, elastic, and allow movement in only specific directions, depending on the individual joint.Embolization, Therapeutic: A method of hemostasis utilizing various agents such as Gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and INTRACRANIAL ARTERIOVENOUS MALFORMATIONS, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage.Anatomy, Artistic: The study of the structures of organisms for applications in art: drawing, painting, sculpture, illustration, etc.Pathology Department, Hospital: Hospital department which administers and provides pathology services.Gamma Cameras: Electronic instruments that produce photographs or cathode-ray tube images of the gamma-ray emissions from organs containing radionuclide tracers.Skull Base: The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Reoperation: A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.Angiography, Digital Subtraction: A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.Blood Vessel Prosthesis Implantation: Surgical insertion of BLOOD VESSEL PROSTHESES to repair injured or diseased blood vessels.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Ultrasonography: The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.Venous Insufficiency: Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Fluorodeoxyglucose F18: The compound is given by intravenous injection to do POSITRON-EMISSION TOMOGRAPHY for the assessment of cerebral and myocardial glucose metabolism in various physiological or pathological states including stroke and myocardial ischemia. It is also employed for the detection of malignant tumors including those of the brain, liver, and thyroid gland. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1162)Iliac Artery: Either of two large arteries originating from the abdominal aorta; they supply blood to the pelvis, abdominal wall and legs.Veins: The vessels carrying blood away from the capillary beds.Diagnostic Imaging: Any visual display of structural or functional patterns of organs or tissues for diagnostic evaluation. It includes measuring physiologic and metabolic responses to physical and chemical stimuli, as well as ultramicroscopy.Cervical Atlas: The first cervical vertebra.Stents: Devices that provide support for tubular structures that are being anastomosed or for body cavities during skin grafting.Aortic Aneurysm, Abdominal: An abnormal balloon- or sac-like dilatation in the wall of the ABDOMINAL AORTA which gives rise to the visceral, the parietal, and the terminal (iliac) branches below the aortic hiatus at the diaphragm.Circle of Willis: A polygonal anastomosis at the base of the brain formed by the internal carotid (CAROTID ARTERY, INTERNAL), proximal parts of the anterior, middle, and posterior cerebral arteries (ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; POSTERIOR CEREBRAL ARTERY), the anterior communicating artery and the posterior communicating arteries.Telepathology: Transmission and interpretation of tissue specimens via remote telecommunication, generally for the purpose of diagnosis or consultation but may also be used for continuing education.Anterior Cruciate Ligament Reconstruction: Rebuilding of the ANTERIOR CRUCIATE LIGAMENT to restore functional stability of the knee. AUTOGRAFTING or ALLOGRAFTING of tissues is often used.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Intracranial Aneurysm: Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)Radiographic Image Interpretation, Computer-Assisted: Computer systems or networks designed to provide radiographic interpretive information.Cerebral Angiography: Radiography of the vascular system of the brain after injection of a contrast medium.Arachnoid: A delicate membrane enveloping the brain and spinal cord. It lies between the PIA MATER and the DURA MATER. It is separated from the pia mater by the subarachnoid cavity which is filled with CEREBROSPINAL FLUID.Sacrum: Five fused VERTEBRAE forming a triangle-shaped structure at the back of the PELVIS. It articulates superiorly with the LUMBAR VERTEBRAE, inferiorly with the COCCYX, and anteriorly with the ILIUM of the PELVIS. The sacrum strengthens and stabilizes the PELVIS.Ultrasonography, Doppler, Duplex: Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.Sphenoid Bone: An irregular unpaired bone situated at the SKULL BASE and wedged between the frontal, temporal, and occipital bones (FRONTAL BONE; TEMPORAL BONE; OCCIPITAL BONE). Sphenoid bone consists of a median body and three pairs of processes resembling a bat with spread wings. The body is hollowed out in its inferior to form two large cavities (SPHENOID SINUS).Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Equipment Design: Methods of creating machines and devices.Ultrasonography, Prenatal: The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.Body Surface Potential Mapping: Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in Wolff-Parkinson-White syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (Braunwald, Heart Disease, 4th ed)Transposition of Great Vessels: A congenital cardiovascular malformation in which the AORTA arises entirely from the RIGHT VENTRICLE, and the PULMONARY ARTERY arises from the LEFT VENTRICLE. Consequently, the pulmonary and the systemic circulations are parallel and not sequential, so that the venous return from the peripheral circulation is re-circulated by the right ventricle via aorta to the systemic circulation without being oxygenated in the lungs. This is a potentially lethal form of heart disease in newborns and infants.Heart Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Electrophysiologic Techniques, Cardiac: Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.Heart Conduction System: An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Ischium: One of three bones that make up the coxal bone of the pelvic girdle. In tetrapods, it is the part of the pelvis that projects backward on the ventral side, and in primates, it bears the weight of the sitting animal.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Reconstructive Surgical Procedures: Procedures used to reconstruct, restore, or improve defective, damaged, or missing structures.Tomography, Spiral Computed: Computed tomography where there is continuous X-ray exposure to the patient while being transported in a spiral or helical pattern through the beam of irradiation. This provides improved three-dimensional contrast and spatial resolution compared to conventional computed tomography, where data is obtained and computed from individual sequential exposures.Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Clavicle: A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Vascular Surgical Procedures: Operative procedures for the treatment of vascular disorders.Phantoms, Imaging: Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)Larynx: A tubular organ of VOICE production. It is located in the anterior neck, superior to the TRACHEA and inferior to the tongue and HYOID BONE.Respiratory Dead Space: That part of the RESPIRATORY TRACT or the air within the respiratory tract that does not exchange OXYGEN and CARBON DIOXIDE with pulmonary capillary blood.Feasibility Studies: Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.Endoscopy: Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.Atlases as Topic: Collections of illustrative plates, charts, etc., usually with explanatory captions.Whole Body Imaging: The creation of a visual display of the inside of the entire body of a human or animal for the purposes of diagnostic evaluation. This is most commonly achieved by using MAGNETIC RESONANCE IMAGING; or POSITRON EMISSION TOMOGRAPHY.Constriction, Pathologic: The condition of an anatomical structure's being constricted beyond normal dimensions.Radiographic Image Enhancement: Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed.Anatomic Variation: Peculiarities associated with the internal structure, form, topology, or architecture of organisms that distinguishes them from others of the same species or group.Stereotaxic Techniques: Techniques used mostly during brain surgery which use a system of three-dimensional coordinates to locate the site to be operated on.Endoscopes: Instruments for the visual examination of interior structures of the body. There are rigid endoscopes and flexible fiberoptic endoscopes for various types of viewing in ENDOSCOPY.Fracture Fixation, Internal: The use of internal devices (metal plates, nails, rods, etc.) to hold the position of a fracture in proper alignment.Basal Ganglia Cerebrovascular Disease: A pathological condition caused by impaired blood flow in the basal regions of cerebral hemispheres (BASAL GANGLIA), such as INFARCTION; HEMORRHAGE; or ISCHEMIA in vessels of this brain region including the lateral lenticulostriate arteries. Primary clinical manifestations include involuntary movements (DYSKINESIAS) and muscle weakness (HEMIPARESIS).Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Occipital Bone: Part of the back and base of the CRANIUM that encloses the FORAMEN MAGNUM.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Surgical Procedures, Minimally Invasive: Procedures that avoid use of open, invasive surgery in favor of closed or local surgery. These generally involve use of laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device.Pathology, Clinical: A subspecialty of pathology applied to the solution of clinical problems, especially the use of laboratory methods in clinical diagnosis. (Dorland, 28th ed.)Gynecologic Surgical Procedures: Surgery performed on the female genitalia.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Intraoperative Complications: Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.Ilium: The largest of three bones that make up each half of the pelvic girdle.Replantation: Restoration of an organ or other structure to its original site.Pharynx: A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx).Keratomileusis, Laser In Situ: A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.Bone Screws: Specialized devices used in ORTHOPEDIC SURGERY to repair bone fractures.Diffusion Magnetic Resonance Imaging: A diagnostic technique that incorporates the measurement of molecular diffusion (such as water or metabolites) for tissue assessment by MRI. The degree of molecular movement can be measured by changes of apparent diffusion coefficient (ADC) with time, as reflected by tissue microstructure. Diffusion MRI has been used to study BRAIN ISCHEMIA and tumor response to treatment.Superior Sagittal Sinus: The long large endothelium-lined venous channel on the top outer surface of the brain. It receives blood from a vein in the nasal cavity, runs backwards, and gradually increases in size as blood drains from veins of the brain and the DURA MATER. Near the lower back of the CRANIUM, the superior sagittal sinus deviates to one side (usually the right) and continues on as one of the TRANSVERSE SINUSES.Balanced Anesthesia: The use of several ANESTHETICS together in small amounts, as opposed to a larger amount of one drug, to induce loss of sensation and loss of consciousness.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Neck: The part of a human or animal body connecting the HEAD to the rest of the body.Visible Human Projects: Digital image data sets, consisting of complete, anatomically detailed, three-dimensional representations of the normal male and female human bodies.Atrial Flutter: Rapid, irregular atrial contractions caused by a block of electrical impulse conduction in the right atrium and a reentrant wave front traveling up the inter-atrial septum and down the right atrial free wall or vice versa. Unlike ATRIAL FIBRILLATION which is caused by abnormal impulse generation, typical atrial flutter is caused by abnormal impulse conduction. As in atrial fibrillation, patients with atrial flutter cannot effectively pump blood into the lower chambers of the heart (HEART VENTRICLES).Arterial Occlusive Diseases: Pathological processes which result in the partial or complete obstruction of ARTERIES. They are characterized by greatly reduced or absence of blood flow through these vessels. They are also known as arterial insufficiency.Medical Illustration: The field which deals with illustrative clarification of biomedical concepts, as in the use of diagrams and drawings. The illustration may be produced by hand, photography, computer, or other electronic or mechanical methods.Infant, Newborn: An infant during the first month after birth.Multidetector Computed Tomography: Types of spiral computed tomography technology in which multiple slices of data are acquired simultaneously improving the resolution over single slice acquisition technology.Fractures, Malunited: Union of the fragments of a fractured bone in a faulty or abnormal position. If two bones parallel to one another unite by osseous tissue, the result is a crossunion. (From Manual of Orthopaedic Terminology, 4th ed)Recurrence: The return of a sign, symptom, or disease after a remission.Rectocele: Herniation of the RECTUM into the VAGINA.Skin Neoplasms: Tumors or cancer of the SKIN.Tomography, Optical Coherence: An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.Ligaments: Shiny, flexible bands of fibrous tissue connecting together articular extremities of bones. They are pliant, tough, and inextensile.Anal Canal: The terminal segment of the LARGE INTESTINE, beginning from the ampulla of the RECTUM and ending at the anus.Rupture: Forcible or traumatic tear or break of an organ or other soft part of the body.Ankylosis: Fixation and immobility of a joint.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Pelvic Organ Prolapse: Abnormal descent of a pelvic organ resulting in the protrusion of the organ beyond its normal anatomical confines. Symptoms often include vaginal discomfort, DYSPAREUNIA; URINARY STRESS INCONTINENCE; and FECAL INCONTINENCE.Longitudinal Ligaments: Two extensive fibrous bands running the length of the vertebral column. The anterior longitudinal ligament (ligamentum longitudinale anterius; lacertus medius) interconnects the anterior surfaces of the vertebral bodies; the posterior longitudinal ligament (ligamentum longitudinale posterius) interconnects the posterior surfaces. The commonest clinical consideration is OSSIFICATION OF POSTERIOR LONGITUDINAL LIGAMENT. (From Stedman, 25th ed)Iliac Vein: A vein on either side of the body which is formed by the union of the external and internal iliac veins and passes upward to join with its fellow of the opposite side to form the inferior vena cava.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Aorta, Abdominal: The aorta from the DIAPHRAGM to the bifurcation into the right and left common iliac arteries.Ultrasonography, Interventional: The use of ultrasound to guide minimally invasive surgical procedures such as needle ASPIRATION BIOPSY; DRAINAGE; etc. Its widest application is intravascular ultrasound imaging but it is useful also in urology and intra-abdominal conditions.Corrosion Casting: A tissue preparation technique that involves the injecting of plastic (acrylates) into blood vessels or other hollow viscera and treating the tissue with a caustic substance. This results in a negative copy or a solid replica of the enclosed space of the tissue that is ready for viewing under a scanning electron microscope.Blood Vessel Prosthesis: Device constructed of either synthetic or biological material that is used for the repair of injured or diseased blood vessels.Popliteal Vein: The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein.Lumbar Vertebrae: VERTEBRAE in the region of the lower BACK below the THORACIC VERTEBRAE and above the SACRAL VERTEBRAE.Head: The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.Avastrovirus: A genus of ASTROVIRIDAE infecting avian species and often involving extra-intestinal manifestations. The type species is Turkey astrovirus.Endovascular Procedures: Minimally invasive procedures, diagnostic or therapeutic, performed within the BLOOD VESSELS. They may be perfomed via ANGIOSCOPY; INTERVENTIONAL MAGNETIC RESONANCE IMAGING; INTERVENTIONAL RADIOGRAPHY; or INTERVENTIONAL ULTRASONOGRAPHY.Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Patient Selection: Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.Bone Malalignment: Displacement of bones out of line in relation to joints. It may be congenital or traumatic in origin.Fat Emulsions, Intravenous: Emulsions of fats or lipids used primarily in parenteral feeding.Pubic Bone: A bone that forms the lower and anterior part of each side of the hip bone.Nerve Compression Syndromes: Mechanical compression of nerves or nerve roots from internal or external causes. These may result in a conduction block to nerve impulses (due to MYELIN SHEATH dysfunction) or axonal loss. The nerve and nerve sheath injuries may be caused by ISCHEMIA; INFLAMMATION; or a direct mechanical effect.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.Hepatectomy: Excision of all or part of the liver. (Dorland, 28th ed)Artifacts: Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.Ligamentum Flavum: The paired bands of yellow elastic tissue that connect adjoining laminae of the vertebrae. With the laminae, it forms the posterior wall of the spinal canal and helps hold the body erect.Fascia: Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests MUSCLES, nerves, and other organs.Sulfanilic Acids: Aminobenzenesulfonic acids. Organic acids that are used in the manufacture of dyes and organic chemicals and as reagents.Terminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.History, Medieval: The period of history from the year 500 through 1450 of the common era.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.Tachycardia, Atrioventricular Nodal Reentry: Abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of ATRIOVENTRICULAR NODE. The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute.Astronauts: Members of spacecraft crew including those who travel in space, and those in training for space flight. (From Webster, 10th ed; Jane's Aerospace Dictionary, 3d ed)Epiphyses: The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united.Spine: The spinal or vertebral column.Tendons: Fibrous bands or cords of CONNECTIVE TISSUE at the ends of SKELETAL MUSCLE FIBERS that serve to attach the MUSCLES to bones and other structures.Arthroscopy: Endoscopic examination, therapy and surgery of the joint.Azygos Vein: A vein which arises from the right ascending lumbar vein or the vena cava, enters the thorax through the aortic orifice in the diaphragm, and terminates in the superior vena cava.Melanoma: A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)Atrioventricular Node: A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Needles: Sharp instruments used for puncturing or suturing.Cardiac Catheterization: Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.Ganglion Cysts: Nodular tumor-like lesions or mucoid flesh, arising from tendon sheaths, LIGAMENTS, or JOINT CAPSULE, especially of the hands, wrists, or feet. They are not true cysts as they lack epithelial wall. They are distinguished from SYNOVIAL CYSTS by the lack of communication with a joint cavity or the SYNOVIAL MEMBRANE.Intracranial Arteriovenous Malformations: Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.Models, Cardiovascular: Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Tomography Scanners, X-Ray Computed: X-ray image-detecting devices that make a focused image of body structures lying in a predetermined plane from which more complex images are computed.Coronary Vessels: The veins and arteries of the HEART.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.Tachycardia, Ectopic Atrial: Abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the HEART ATRIUM but away from the SINOATRIAL NODE. Unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. The episode is characterized by a HEART RATE between 135 to less than 200 beats per minute and lasting 30 seconds or longer.Retroperitoneal Space: An area occupying the most posterior aspect of the ABDOMINAL CAVITY. It is bounded laterally by the borders of the quadratus lumborum muscles and extends from the DIAPHRAGM to the brim of the true PELVIS, where it continues as the pelvic extraperitoneal space.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Anterior Cerebral Artery: Artery formed by the bifurcation of the internal carotid artery (CAROTID ARTERY, INTERNAL). Branches of the anterior cerebral artery supply the CAUDATE NUCLEUS; INTERNAL CAPSULE; PUTAMEN; SEPTAL NUCLEI; GYRUS CINGULI; and surfaces of the FRONTAL LOBE and PARIETAL LOBE.