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An alphabetical listing of General terms and items. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

P-VALUE   A measure of probability that is reported with clinical trial results. The p-value indicates the likelihood the result obtained are due to chance alone. Traditionally, a p-value of less than .05 is considered statistically significant, or not likely due to chance alone. See also confidence interval. Pachymeninx   Greek pachys = thick, and meninx = membrane; hence, the thick membrane covering the central nervous system, i.e., dura mater. Paget's Disease   A disease characterized by accelerated bone turnover, resulting in the involved bone becoming enlarged but weak and fragile. The bone also feels warmer to touch due to increased blood supply. Also called osteitis deformans. Palaeo   Greek palaios = old; hence, palaeocerebellum, the earliest stage in the evolution of the cerebellum. Palate   Latin palatum = palate, adjective - palatal or palatine. Paleo   Greek palaios = old; hence, paleocerebellum, the earliest stage in the evolution of the cerebellum. PALLIATIVE   Offering symptomatic relief and comfort care (e.g., alleviation of pain) rather than a cure. Pallidus   Adjective, Latin = pale. Pallium   Latin = cloak; hence, the cerebral cortex forming the outer covering of the cerebral hemisphere. PALLOR   Paleness. Palma   Latin palma = palm; adjective, palmar - Latin palmaris. Palpable   Able to be felt (see Breast Cancer). Palpate   Latin palpare = to touch, and palpatus = touched; hence, to examine by feeling, and palpation, such an examination. Palpebra   Latin = eyelid, probably from palpitare = to flutter. Pampiniform   Adjective, Latin pampinus = tendril, and forma = shape. PANCREAS   A digestive gland in the abdominal cavity that secretes digestive enzymes. PANCREATITIS   Inflammation of the pancreas. PANCYTOPENIA   An abnormally low level of all types of blood cells, typically due to bone marrow damage. Panniculus   Diminutive of Latin pannus = cloth. Papilla   Latin = nipple or teat; adjective - papillary. Back to top PARACENTESIS   A procedure to remove fluid that has accumulated in the abdominal cavity—a condition called ascites. PARACETOMAL   See acetaminophen Paradidymis   Greek para = beside of near, and didymis = twinned or paired, refers to testes; hence the collection of convoluted tubules in the spermatic cord, above the head of the epididymis. Paraesthesia   Greek para = beside, and aisthesia = sensation; hence, abnormal sensation, usually burning or pricking. Paralysis   Greek para = beside, near, lyein = to loosen; hence loss or impairment of muscle function. Parametrium   Greek para = beside, and metra = womb; hence, connective tissue alongside the body of the uterus, within the broad ligament. Paraplegia   Greek para = beside, and plege = a stroke; hence, paralysis of the lower limbs. Pararenal   Adjective, Greek para = beside, Latin ren = kidney; hence, beside the kidney, e.g., pararenal fat, the fatty capsule of the kidney. Parasternal   Adjective, Greek para = beside, and sternon = chest; hence, the parasternal line is a vertical line about midway between the sternal edge and the midclavicular line. Parasympathetic   Adjective, Greek para = beside, syn = with, and pathos = feeling; hence, the division of the autonomic nervous system complementary to the sympathetic system. Parathyroid   Adjective, Greek para = beside, and thyroid; hence, beside the thyroid gland. Parathyroid Hormone (PTH)   A hormone that regulates calcium levels. It prevents the level of blood calcium from going too low by stimulating the breakdown of bone. In addition to triggering bone loss, it can stimulate bone formation. Given appropriately, it can increase bone mass, and is used as a treatment for osteoporosis (see Osteoporosis). Parenchyma   Greek para = beside or near, en = in, and chein = to pour; hence a general term to designate the functional elements of an organ, as opposed to the framework or stroma. PARENTERAL   Nutrients given by injection into a vein, bypassing the gastrointestinal tract. Paresis   Greek = relaxation, but has come to mean partial paralysis. Parietal   Adjective, Latin parietalis, pertaining to paries = wall. Parotid   Adjective, Greek para = beside, and otos = of the ear; hence, beside the ear. Parous   Adjective, Latin pario = I bear (children); hence, adjective, applied to woman who has borne one or more children (cf. nulliparous, multiparous). Pars   Latin = part. Patch Test   A skin test used to diagnose contact dermatitis (see Allergies). Back to top Patella   Latin a small pan; adjective - patellar. PATHOGEN (adjective PATHOGENIC)   Any disease-causing agent, especially a microorganism (bacteria, virus, fungus, parasite). PATHOGENESIS   The development and progression of a disease. PATHOLOGY (adjective PATHOLOGIC)   The study of disease, including the causes, development, and progression of disease, and how the body is affected. Pauciarthritis   Same as oligoarthritis. PCR   See polymerase chain reaction. PD   Peritoneal dialysis Peak Bone Mass   The greatest amount of bone tissue that a person has during his or her life; typically reached by age 30 (see Osteoporosis). Peak Flow   A measure of how fast you can blow air out of your lungs. In asthma, your peak flow reflects the extent to which your bronchial tubes are normally open or abnormally narrowed (see Asthma). Peak Flow Meter   A simple handheld device used to assess lung function, commonly used to diagnose and monitor asthma (see Allergies, Asthma). PEAK LEVEL   The highest level of drug reached in the body after a dose is taken. Contrast with trough level. Pecten   Latin = comb. Pectinate   Adjective, from Latin pecten = a comb; applied to structures having the appearance of parallel teeth arising from a straight back (musculi pectinati), or the sellar appearance of the superior pubic ramus, which may have resembled the body of antique combs. Pectineal   Adjective, from Latin pecten = a comb; applied to structures having the appearance of parallel teeth arising from a straight back (musculi pectinati), or the sellar appearance of the superior pubic ramus, which may have resembled the body of antique combs. Pectineus   Latin, pecten = a comb; hence the muscle attaching to the pecten (pectineal line) of the pubic bone. Pectoral   Adjective, Latin pectoris = of the front of the chest. Pectoralis   Adjective, Latin pectoris = of the front of the chest. Pedicle   Diminutive of Latin pedis = of the foot. Pedis   Latin = of the foot. Peduncle   Variation of pedicle. Back to top PEG-INTRON   Brand name of pegylated interferon-alpha-2b, produced by Schering-Plough. PEGASYS   Brand name of pegylated interferon-alpha-2a, produced by Genentech Inc. PEGINTERFERON   See pegylated interferon. PEGYLATED INTERFERON (PEGINTERFERON)   A recently developed form of interferon that has a long half-life in the body and can be injected less often (typically once per week). Pegylated interferon (brand names Peg-Intron, Pegasys) appears superior to standard interferon as a treatment for HCV. PEGYLATION   A process in which polyethylene glycol (PEG) molecules are attached to proteins in order to extend their activity in the body. PEI   See percutaneous ethanol injection. Pellucidum   Adjective, Latin per = through, and lucere - to shine; hence, translucent. Pelvic Floor   The supportive network of muscles that extends from the pubic bone to the tailbone with openings for the urethra, the anus, and in women, the vagina (see Urinary Incontinence). Pelvis   The bony structures in the lowest part of the trunk. The term pelvic is used for anything that belongs or refers to the pelvis. Penis   Latin = tail, the male organ of copulation (cf. appendix, appendage). Pennate   Latin penna = feather; hence, a muscle whose fibres approach the tendon from one direction is unipennate; from two, bipennate, and from more than two, multipennate. Pennatus   (pinnate) - adjective, Latin penna = feather; hence, a muscle whose fibres approach the tendon from one direction is unipennate; from two, bipennate, and from more than two, multipennate. Pepsin   A name for several enzymes secreted by the stomach to break down protein (see Digestive Health). Peptic Ulcer   A sore in the lining of the stomach (gastric ulcer) or duodenum (duodenal ulcer). The word peptic refers to the stomach and the duodenum, where pepsin is present, an enzyme that breaks down proteins. An ulcer can sometimes occur in the lower part of the esophagus in association with heartburn. Peptide   A few amino acids linked together. Proteins are made of multiple pep tides linked together. PERCUTANEOUS   Through the skin. PERCUTANEOUS ETHANOL INJECTION   A treatment for hepatocellular carcinoma in which ethanol (alcohol) is injected into the tumor. Perianal   Adjective, Greek peri = around, and Latin anus = lower opening of alimentary canal. Pericardium   Greek peri = around, and kardia = heart; hence, the membranes enclosing the heart. Perichondrium   Greek peri = around, and chondros = cartilage; hence, the membrane covering cartilage. Back to top Pericranium   Greek peri = around, and kranion = skull; hence, the external periosteum of the skull. PERIHEPATITIS   Inflammation of the lining of the liver. Perilymph   Greek peri = around, and lympha - Latin = clear water; hence, the fluid in the bony labyrinth surrounding the membranous labyrinth (and continuous with the cerebrospinal fluid). Perimenopause   The phase starting when periods become irregular and lasting until a year after the last period (see Menopause). PERINATAL   The period around the time of birth. PERINATAL TRANSMISSION   See vertical transmission. Perineum   Greek the caudal aspect of the trunk between the thighs, or, the region of the trunk below the pelvic diaphragm; adjective - perineal. Periodontal   Adjective, Greek peri = around, and odont = tooth. Periosteum   Greek peri = around, and osteon = bone; hence, the membrane around a bone. Peripheral   Adjective, Greek peri = around and phero = carry; hence, away from the centre (cf. periphery). PERIPHERAL NEUROPATHY   Damage to the peripheral nerves, usually involving the feet and hands. Peripheral Vascular Disease   A disorder caused by the blockage of blood vessels to the brain and extremities (see Diabetes). Peristalsis   Greek peri = around, and stellein - to constrict; hence, a circular constriction passing as a wave along a tube; adjective - peristaltic. PERITONEUM   The thick membrane that lines the abdominal cavity and covers the visceral organs. PERITONITIS   Inflammation of the peritoneum. PERNICIOUS ANEMIA   A type of anemia caused by the inability of the intestine to absorb vitamin B12, which is needed to produce red blood cells. Perometer   An electromechanical device that electronically gathers data that is then used to calculate limb volume. Peroneal   Adjective, Greek perone = clasp, brooch - see fibula. Pes   Latin = foot. Pessary   A device worn in the vagina to support or correct the position of the uterus, rectum, or bladder (see Urinary Incontinence). Back to top Petrosal   Adjective, Latin petrosus = rocky. Petrous   Adjective, Latin petrosus = rocky. PHAEO   Darkly pigmented. PHAGOCYTE   A scavenger cell that engulfs and destroys invading pathogens (phagocytosis). Phalanx   Latin = row of soldiers; hence, one of the small bones of a digit, plural - phalanges, adjective - phalangeal. Phallus   Greek phallos = penis. PHARMACEUTICAL   Having to do with the development and manufacture of drugs, or to a manufactured drug. PHARMACOKINETICS   The action of drugs in the body, including the processes of absorption, metabolism, distribution to tissues, and elimination. PHARMACOLOGY   The science of drugs, their sources, and how they work. Pharynx   Greek = throat; adjective - pharyngeal. PHASE I TRIAL   The first stage of human testing of a new treatment. Phase I trials evaluate drug pharmacokinetics, safety, and toxicity at different dose levels, typically in a small number of healthy volunteers. PHASE II TRIAL   The second stage of the evaluation of a new treatment in humans. Phase II trials evaluate safety and preliminary efficacy in a larger number of participants than Phase I studies. PHASE III TRIAL   The third stage of human testing of an experimental treatment. Phase III trials are designed to determine the efficacy of a treatment, often by comparing it to an existing standard therapy or a placebo. PHASE IV TRIAL   Post-marketing studies done after a new treatment is approved and offered for sale. These trials provide additional information about safety and efficacy in large numbers of patients under "real world" conditions. Philtrum   Greek philtron - the median sulcus of the upper lip. Derivation doubtful. Phlebolymphedema   Another term meaning chronic venous insufficiency. Also spelled phelbo-lymphedema. PHLEBOTOMY   Withdrawal of blood from a vein. Phonation   Greek phone = sound or voice; hence, the production of either. PHOTOSENSITIVITY   An increased sensitivity to light, which may lead to easy sunburning and other adverse effects. Phrenic   Greek phren = diaphragm or mind; hence, diaphragmatic (cf. schizophrenic). Back to top PHYLLANTHUS   Tropical plant species that traditionally have been used to treat liver conditions. Pia   Latin = faithful, hence, the membrane which faithfully follows the contour of the brain and spinal cord. PIGMENT   A substance responsible for the color of bodily tissues. Pilomotor   Latin pilus = a hair, and movere = to move; hence the action of the arrectores pilorum muscles. Pilus   Latin = a hair. Pineal   Adjective, Latin pinea = a pine cone; hence, the pineal gland which is cone-shaped. Piriform   Adjective, Latin pirum = a pear; hence, pear-shaped. Pisiform   Adjective, Latin pisum = a pea; hence, pea-shaped. Pitting Edema   When a swollen area is pressed, the pressure leaves an indentation (pit) that slowly fills in again. Pituitary   Latin pituita = mucous or phlegm, the gland was thought to produce mucous that discharged through the nose. Pituitary Gland   An endocrine gland tucked into a bony space beneath the brain. It receives input and influence from the hypothalamus. It produces adrenocorticotropic hormone (ACTH), which controls the secretion of cortisol by the adrenal glands. This helps trigger the "fight-or-flight" response (see Anxiety, Depression). PLACEBO   An inert, inactive agent (e.g., pill, injection) that has no treatment value. PLACEBO ARM   The group of participants in a clinical trial that receives an inactive substance (placebo). PLACEBO EFFECT   A change in symptoms or disease progression associated with the treatment process itself, rather than the actual therapeutic value of a treatment. PLACEBO-CONTROLLED TRIAL   A clinical trial in which a group receiving an inactive substance or mock therapy (placebo) is compared to a group receiving the experimental treatment. PLACENTA   The organ that connects the fetus and the mother's uterus and enables the exchange of oxygen, nutrients, and waste products. Placode   Greek plax = plate or flat, and eidos = shape or form. Plane   Latin planus = flat; hence, a real or imaginary flat surface. Planta   Latin the sole of the foot; adjective - plantar or plantaris. Plantar   Adjective, Latin planta = the sole of the foot. Back to top Plaque   Deposits of cholesterol and fatty and fibrous substances in the walls of the arteries (see Cardiovascular Health). PLASMA   The fluid, non-cellular portion of circulating blood. See also serum. Plasma Cells   Descendants of B cells responsible for producing antibodies (see Allergies). PLASMAPHERESIS   A procedure in which certain components are removed from the blood plasma. PLATELET   See thrombocyte. PLATELET COUNT   The number of platelets in the blood. People with advanced liver disease may have reduced platelet counts, resulting in easy bleeding. A normal platelet count is 130,000-400,000/mcl. Platelets   Minute, colorless disks in the blood that are instrumental in clotting (see Cardiovascular Health, High Cholesterol). Platysma   Greek = flat object; hence, the flat subcutaneous muscle extending from below the clavicle to the mouth. Pleura   Greek = a rib. Later used to name the serous membrane lining the chest walls and the lung on each side. Plexus   Latin = a network or plait. Plica   Latin plicare = to fold; hence, a fold. Pneumon   Greek pneuma = air. PNEUMONITIS   Lung inflammation. PO   Taken by mouth. Pollex   Latin = thumb. Pollicis   Genitive (possessive case) of Latin pollex = thumb; hence of the thumb. Polyarthralgia   Pains in many joints; conventionally refers to more than four joints, without signs of inflammation in the symptomatic joints. Polyarthritis   Inflammation in many joints; conventionally in more than four joints. POLYMERASE CHAIN REACTION (PCR)   A highly sensitive test that uses an amplification technique to detect small amounts of genetic material (DNA or RNA) in a blood or tissue sample. POLYMERASE INHIBITOR   An agent that inhibits viral replication by interfering with the polymerase enzyme. Back to top Polyunsaturated Fats   Fatty acids that are abundant in soybean, corn, cottonseed, safflower, and sunflower oils (see High Cholesterol). Pons   Latin = bridge; adjective - pontine; part of the brain stem. Popliteus   Latin poples = the ham or thigh, and sometimes, the knee; adjective, popliteal, referring to the fossa behind the knee or its contents. PORPHYRIA CUTANEA TARDA   A condition in which porphyrins build up in the body leading to symptoms including increased photosensitivity, skin damage, and discoloration. PORPHYRIN   A metabolic byproduct of hemoglobin production. Porta   Latin = a gate, also Latin portare = to carry; hence, the portal system carries venous blood from the alimentary tract to the porta hepatis; adjective - portal. PORTAL HYPERTENSION   High blood pressure in the portal vein that carries blood to the liver, caused by the development of fibrous scar tissue (cirrhosis) in the liver. PORTAL SYSTEM   A series of veins from the small and large intestines, stomach, and spleen that join into the portal vein and are carried into the liver. PORTAL VEIN   The blood vessel that carries oxygen-poor blood from the intestines to the liver for filtering. Porus   Latin a pore or foramen; hence, the openings of the acoustic meatuses. POST-MARKETING STUDY   See Phase IV trial. Posterior   Adjective, Latin post = behind (in place or time). POSTEXPOSURE PREVENTION (POSTEXPOSURE PROPHYLAXIS,   Treatment given immediately following exposure to an infectious organism in an attempt to prevent the infection from taking hold in the body. POSTEXPOSURE PREVENTION (POSTEXPOSURE PROPHYLAXIS,   Treatment given immediately following exposure to an infectious organism in an attempt to prevent the infection from taking hold in the body. POSTNATAL (POSTPARTUM)   The period following birth. Posture   Latin positus = placed; hence, the position of the body as a whole at a given moment, e.g. erect, recumbent, prone, supine, sitting, kneeling. POTASSIUM   An element and electrolyte responsible for the body’s growth and maintenance. POWER   A statistical term used to describe the ability of a clinical trial to detect a particular result. Generally the power of a study increases as more participants are included or as the trial continues for a longer period of time. PRANA   In Ayurveda, the body's vital energy. Pre-diabetes   A condition in which a fasting plasma glucose test and/or an oral glucose tolerance test provide readings that are elevated, but not quite diabetic; raises the risk of diabetes (see Diabetes). Back to top PRECLINICAL RESEARCH   Laboratory and animal studies on an experimental treatment prior to clinical trials in humans. Preclininical Stage   The potential development of Lymphedema before clinical indications, such as swelling, are observed. Precuneus   Latin pre = before, and cuneus = wedge; hence, the parietal lobule anterior to the cuneus. Prehypertension   A condition that increases the risk of developing high blood pressure; defined as 120–139 mm Hg systolic pressure or 80–89 diastolic pressure (see Cardiovascular Health). PRENATAL   The period preceding birth, during which the fetus develops in the uterus. Prepuce   Latin praeputium = foreskin (of penis or clitoris). Prevalence   The observed number of people in a given population affected with a particular disease or condition at a given time, usually stated as the number of cases observed per 100 000 individuals, or listed as a percentage. In contrast with incidence, prevalence can be thought of as a snapshot of all existing cases at a specified time. PREVALENCE (also PREVALENCE RATE)   The number of individuals with a condition in a specific population. The prevalence rate is determined by dividing the number of people with the condition by the total population. Contrast with incidence. Prick Test   A commonly used skin test to confirm hypersensitivity to a broad range of allergens that elicit an IgE-mediated response (see Allergies). PRIMARY CARE PHYSICIAN   A physician who is responsible for the overall long term health maintenance of a patient. Primary Lymphedema   An inherited form of lymphedema that affects both males and females and can develop at any time of life; PLE. Primary Osteoporosis   Bone loss that doesn't result from an identifiable pathological process (see Osteoporosis). Princeps   Latin primus = chief, and capere = to take; hence chief or principal. PRINCIPLE INVESTIGATOR   The chief researcher conducting a clinical trial. Procerus   Latin = slender, elongated; hence, the vertical slip of muscle between the medial part of frontalis and the root of the nose. Process   Latin = going forwards, used to indicate growing out, i.e., an outgrowth, usually of bone, e.g., the zygomatic process of the temporal. Processus   Latin going forwards, used to indicate growing out, i.e., an outgrowth, usually of bone, e.g., the zygomatic process of the temporal. PROCRIT   See erythropoietin. PRODRUG   A compound that is converted to an active drug within the body. Profundus   Latin pro = before, and fundus = bottom; hence profundus = deep. Back to top PROGESTERONE   A female hormone with anti-estrogen effects. Progesterone prepares the uterus for the development of the fertilized ovum and maintains the uterus throughout pregnancy. Progestin   A synthetic compound that produces effects similar to those of progesterone (see Menopause). Progestogen   Any hormone having the same effect as progesterone in the body; refers to both natural progesterone and synthetic progestin (see Menopause). Prognosis   The probable end result or outcome of a disease. PROGNOSIS (adjective PROGNOSTIC)   A forecast of the probable course or outcome of a disease. PROGRESSION   Development of a disease over time. PROKINE   See granulocyte colony-stimulating factor. Prolapse   When a part of the body drops from its normal position (see Urinary Incontinence). Prominens   Latin = projecting. Promontory   Latin promontorium = a headland, i.e., part of land jutting into the sea - used for a bony prominence. Pronate   Latin pronatus = bent forwards; hence to pronate = to turn the hand so that the palm faces posteriorly. Prone   Latin pronatus = bent forwards; hence, recumbent face-down posture. PROPHYLAXIS   A measure taken to prevent a disease or condition. Proprioceptive   Latin proprius = one's own, and captum = taken; hence, sensory impulses received by the joints and muscles within one's own body. Prosection   Latin pro = before, and sectum = cut. A dissection prepared for demonstration of anatomic structures. Prosector   Latin pro = before, and sectum = cut. One who prepares a dissection for demonstration. Prosencephalon   Latin pro = in front, and Greek enkephalos = brain; hence, the part of the brain rostral to the midbrain. PROSPECTIVE STUDY   A clinical trial in whichparticipants are selected and their progression is followed over time. Contrast with retrospective study. Prospective, Randomized, Double Blind   Study clinical trial or study in which the method of data analysis is specified in a protocol before the study is begun (prospective). Patients are randomly assigned to receive either the study drug or an alternative treatment, and neither the patient nor the doctor conducting the study knows which treatment is being given to which patient (see also placebo). Prostate   Greek pro = before, and Latin = statum = stood; hence, something which stands before - the prostate stands before the urinary bladder. Back to top PROTEASE INHIBITOR   An agent that inhibits viral replication by interfering with the virus' protease enzyme. PROTEIN   A complex organic compound consisting of a sequence of amino acids folded in a specific configuration. Proteins are major components of living cells and are essential for bodily growth and repair. PROTHROMBIN   A protein synthesized by the liver that is necessary for proper blood clotting. PROTHROMBIN TIME (PT)   A measure of blood clotting time. People with advanced liver disease may have a slower than normal PT. A normal PT is 10-12 seconds. PROTOCOL   A written plan for a clinical trial, which typically includes details such as the hypothesis to be tested, who can participate, length of the trial, how the treatment under study will be administered, endpoints, and potential risks and benefits. Proton Pump Inhibitors   A group of drugs used to treat heartburn and peptic ulcer disease. These include omprezole (Prilosec), esomeprazole (Nexium) and pansoprazole (Prevacid). Protract   Latin protractus = drawn out; hence, to put forwards (e.g., shoulder or mandible). Protraction - the act of protracting. Protrude   Latin protrudo = thrust forwards, e.g. the tongue; protrusion - the act of protruding. Protuberance   Latin protubero = I bulge out; hence, a bulging bony feature (see tuber). Proximal   The part of a limb that is closest to the trunk. For example, the shoulder joint forms the proximal end of the upper extremity (opposite of distal). PRURITUS (adjective PRURITIC)   Itchiness. PSEUDOHYPHA (pl. Pseudohyphae)   A fragile string of cells that result from the budding of blastoconidia that have remained attached to each other. The septa separating the cells are complete and there is no cytoplasmic connection, as is found in most true septate hypha. Psoas   Greek = loin. PSORIASIS   A skin condition characterized by scaling and red patches, due to the overproduction of skin cells. PSORIATIC ARTHRITIS   A form of rheumatoid arthritis associated with psoriasis. Psychodynamic Therapy   A form of therapy that focuses on how life events, desires, and close relationships lead to conflict, symptoms such as anxiety or depression, and difficulty in managing life's tasks (see Depression). PSYCHOSIS   A serious mental illness. PSYCHOSOCIAL   A term used to refer to factors that affect the psychological or social realm. Psychosocial factors (e.g., socioeconomic status, education, family situation) can have an important effect on disease risk and progression and are an essential aspect of a person's well-being. PSYCHOTHERAPY   Treatment of mental problems with non-medical therapies, in particular counseling. PSYCHOTROPIC   A drug that affects psychological or mental functioning or behavior. Back to top PT   Patient. Pterion   Greek pteron = wing; hence, the region where the tip of the greater wing of the sphenoid meets or is close to the parietal, separating the frontal from the squamous temporal; alternatively the region where these 4 bones meet. Pterygoid   Adjective, Greek pteryx = wing, and eidos = shape; hence, wing-shaped. Ptosis   Greek = fall; hence, drooping of an eyelid, or descent of an internal organ. Puberty   Latin puber = adult; hence, the time when hair appears in the pubic region - i.e., near the pubis - as a secondary sexual characteristic. Pubes   Latin = adult or signs of manhood, hence the lower abdominal secondary sexual hair. Pudendal   Adjective, Latin pudendus = shameful; hence, pertaining to the external genitalia. Pudendal Nerve   The nerve that controls the muscles of the pelvic floor; plays an important role in urinary and fecal continence (see Urinary Incontinence). Pulmonary   Adjective, Latin pulmo = lung. PULMONARY FIBROSIS   The development of fibrous tissue in the lungs. Pulp   Latin pulpa = a soft part of the body or tooth. Pulposus   Latin pulpa = a soft part of the body or tooth, hence pulpy or soft. Pulse Pressure   The difference between your systolic and diastolic blood pressures. May help predict heart disease risk (see Hypertension). Pulvinar   Latin pulvinus = rounded cushion; the posterior end of the thalamus. Punctum   Latin = a sharp point; hence a very small point or orifice. Pupil   Latin pupilla = the central black orifice in the iris; adjective - pupillary. PURPURA   See thrombocytopenic purpura. PURULENT   Characterized by the accumulation of pus. PUS   A thick, greenish-yellow fluid composed of dead white blood cells, killed microorganisms, and other cellular debris. Putamen   Latin = peel, husk or shell of fruit or seed (the external part of the lentiform nucleus). Back to top Pyelogram   Greek pyelos = basin, and gramma = diagram; hence, radiograph of the renal pelvis (and usually of the ureter) after filling with contrast medium. Pylorus   Greek = gate-keeper; hence, the part of the pyloric canal containing the sphincter, which guards the opening into the duodenum; adjective - pyloric. Pyramid   Greek pyramis = a pyramid (solid with 3- or more-sided base, and flat sides meeting at the apex), adjective - pyramidal. PYRROLIZIDINE ALKALOID   A hepatotoxic component found in plants of the Crotalaria, Senecio, and Heliotropium families. Back to top