Glossary of medicine

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• Aarskog–Scott syndrome – A rare, inherited disease characterized by short stature, facial abnormalities, skeletal and genital anomalies.
• Abdomen – The part of the body between the chest and pelvis, which contains most of the tubelike organs of the digestive tract, as well as several solid organs.
• Abdominal external oblique muscle – The largest, and outermost, of the three flat muscles of the lateral anterior abdominal wall.
• Abdominal internal oblique muscle – A muscle of the abdominal wall, which lies below the external oblique and just above the transverse abdominal muscles.
• Abductor pollicis brevis muscle – A muscle in the hand that abducts the thumb.
• Abductor pollicis longus muscle – One of the extrinsic muscles of the hand. Its major function is to abduct the thumb at the wrist.
• Abscess – A collection of pus that has built up within the tissue of the body.
• Accommodation – the process by which the eye focuses on an object.
• Accommodation reflex – a reflex action of the eye, measured as a response to focusing on a near object, then looking at a distant object.
• Acetabulum – a concave surface of the pelvis, which forms the pelvic section of the hip joint.
• Achilles tendon – a tendon of the back of the leg, and the thickest in the human body. It attaches the plantaris, gastrocnemius and soleus muscles to the calcaneus bone.
• Acne – a long-term skin disease that occurs when hair follicles are clogged with dead skin cells and oil from the skin.
• Acne vulgaris – see Acne
• Acupressure – an alternative medicine technique where pressure is applied to acupuncture points. Pressure may be applied by hand, by elbow, or with various devices.
• Acupuncture – a form of alternative medicine in which thin needles are inserted into the body.
• Adam's apple – the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx seen especially in males.
• Adaptive immune system – also known as the acquired immune system or, more rarely, as the specific immune system, is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate pathogens or prevent their growth.
• Adenoma – is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both.
• Adrenal gland – The adrenal glands are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys.
• Allergy – Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, a runny nose, shortness of breath, or swelling. Food intolerances and food poisoning are separate conditions.
• ADHD – Attention deficit hyperactivity disorder.
• Alzheimer's disease –, also referred to simply as Alzheimer's, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events.
• Anal canal – is the terminal part of the large intestine. It is situated between the rectum and anus, below the level of the pelvic diaphragm. In humans it is approximately 2.5 to 4 cm long. It lies in the anal triangle of perineum in between the right and left ischioanal fossa.
• Anatomy – is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of living things.
• Anesthesiology – Anesthesiology, anaesthesiology, anaesthesia or anaesthetics is the medical speciality concerned with the total perioperative care of patients before, during and after surgery.
• Angiology – is the medical specialty which studies the diseases of the circulatory system and of the lymphatic system, i.e., arteries, veins and lymphatic vessels, and its diseases.
• Ankle – The ankle, or the talocrural region, is the region where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" can refer broadly to the region or specifically to the talocrural joint.
• Anterior tibial artery – The anterior tibial artery of the leg carries blood to the anterior compartment of the leg and dorsal surface of the foot, from the popliteal artery.
• Antibiotic – is a type of antimicrobial substance active against bacteria and is the most important type of antibacterial agent for fighting bacterial infections. Antibiotic medications are widely used in the treatment and prevention of such infections.
• Antibody –, also known as an immunoglobulin, is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.
• Aorta – is the main artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries. The aorta distributes oxygenated blood to all parts of the body through the systemic circulation.
• Appendix – The appendix is a finger-like, blind-ended tube connected to the cecum, from which it develops in the embryo. The cecum is a pouch-like structure of the colon, located at the junction of the small and the large intestines. The term "vermiform" comes from Latin and means "worm-shaped." The appendix used to be considered a vestigial organ, but this view has changed over the past decades.
• Arm – is the part of the upper limb between the glenohumeral joint and the elbow joint. In common usage, the arm extends to the hand. It can be divided into the upper arm, which extends from the shoulder to the elbow, the forearm which extends from the elbow to the hand, and the hand. Anatomically the shoulder girdle with bones and corresponding muscles is by definition a part of the arm. The Latin term brachium may refer to either the arm as a whole or to the upper arm on its own.
• Arteriole – is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Arterioles have muscular walls and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries.
• Artery – is a blood vessel that takes blood away from the heart to all parts of the body. Most arteries carry oxygenated blood; the two exceptions are the pulmonary and the umbilical arteries, which carry deoxygenated blood to the organs that oxygenate it. The effective arterial blood volume is that extracellular fluid which fills the arterial system.
• Arthritis – is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints.
• Asperger syndrome –, also known as Asperger's, is a developmental disorder characterized by significant difficulties in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior and interests. As a milder autism spectrum disorder, it differs from other ASDs by relatively normal language and intelligence. Although not required for diagnosis, physical clumsiness and unusual use of language are common.
• Asthma – is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath.
• – absence of muscle tone.
• Atrial fibrillation – is an abnormal heart rhythm characterized by rapid and irregular beating of the atria. Often it starts as brief periods of abnormal beating which become longer and possibly constant over time. Often episodes have no symptoms.
• Attention deficit hyperactivity disorder – is a mental disorder of the neurodevelopmental type. It is characterized by problems paying attention, excessive activity, or difficulty controlling behavior which is not appropriate for a person's age.
• Auscultation – is listening to the internal sounds of the body, usually using a stethoscope. Auscultation is performed for the purposes of examining the circulatory and respiratory systems, as well as the gastrointestinal system.
• Autism – is a developmental disorder characterized by troubles with social interaction and communication, and by restricted and repetitive behavior. Parents usually notice signs during the first two or three years of their child's life. These signs often develop gradually, though some children with autism reach their developmental milestones at a normal pace before worsening.
• Axilla – is the area on the human body directly under the joint where the arm connects to the shoulder. It also provides the under-arm sweat gland.
• Axillary artery – is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla and the upper limb. Its origin is at the lateral margin of the first rib, before which it is called the subclavian artery.