Medical Terminology Glossary: [P]
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Pacemaker Specialised tissue within heart muscle generating rhythmical electrical impulses which trigger contraction of the myocardium.

Pack-Years Average number of packs of cigarettes smoked per day multiplied by the number of years of smoking.

Packed Cells Concentrate of (essentially red) blood cells created by removing the majority of the liquid (plasma) of the donated blood.

Packed, of Red Blood Cells A derivative of whole blood for transfusion, produced by partial removal of fluid (plasma).

Pa_CO2 The concentration (partial pressure) of carbon dioxide in the blood of an artery.

Pain Behaviour Observable actions other than descriptive speech arising out of the experience of pain.

Palpebral Fissures The gap between the upper and lower eyelids.

Pancreas Organ in the upper abdomen producing both enzymes for digestion and insulin.

Pancreatitis, Chronic Chronic inflammation of the pancreas, often causing abdominal pain because of the escape of pancreatic enzymes.

Pancreatitis, Acute Acute inflammation of the pancreas, often causing destruction of pancreatic and other abdominal tissues because of the escape of pancreatic enzymes.

Pancytopenia Pathological deficiency of all the normal blood cells.

Pa_O2 The concentration (partial pressure) of oxygen in the blood of an artery.

Pap(anicolaou) Smear Sampling, by wooden spatula or cytobrush, the lining cells of the cervix and vagina, subsequently examined microscopically for the presence of abnormal cells or evidence of infection.

Papillotomy Surgical incision into the papilla, the protrusion into the duodenum at which the common bile-duct and pancreatic duct empty.

Para-aortic (Lymphnodes) Alongside the aorta, or major bloodvessel carrying oxygen-rich blood to the body.

Paranasal Sinuses Airspaces in the base of the skull in communication with the air passages of the nose.

Paraparesis Weakness of the legs.

Parasternal Alongside the breast-bone.

Parathyroid Hormone, or Parathormone The biologically active substance produced by the parathyroid glands in the neck and acting throughout the body on calcium metabolism.

Paravertebral Alongside the vertebral column.

Partial Thromboplastin Time (PTT) A test of the clotting system, used in the evaluation of the dosage of heparin.

Patella Kneecap.

Pathogenesis Sequential development of a disease process.

Pectus Excavatum A funnel-shaped hollow of the lower part of the chest.

Pedal (Dorsalis Pedis) Pulse An arterial pulse which can be felt on top of the foot in front of the ankle.

Pelvic Congestion (Syndrome), Chronic Chronic overfilling of the veins of the female pelvis, causing aching pain, worse after prolonged standing, sexual intercourse and premenstrually, and characterised possibly by the presence of external varicose veins of the groin and vulva, and certainly by dilated veins of the broad ligament.

Pelvic Pouch Surgically-fashioned artificial rectum.

Pelvic (Inflammatory Disease, Pain) Refers to the cavity, not the walls, of the bony pelvis; Pelvic Inflammatory Disease has the specific meaning of infection, often sexually-transmitted, of the internal female genitals.

Pelvic Floor Strain Partial tearing of the muscles supporting the major pelvic organs (urinary bladder, uterus, rectum.

Pelvic Brim The inlet or boundary between the expanded "false" pelvis above and the cylindrical cavity of the true pelvis below.

Pelvic Examination Assessment of the inner organs of the pelvis by vaginal examination, rather than examination of the bony pelvis.

Pelvic Refers in these instances to the contents of the cavity, not its bony walls.

Pentamidine An antimicrobial agent effective against pneumocystis carinii.

Peptic Ulcer Ulcer usually of the lining of the stomach or duodenum caused by the unprotected damage of acid.

Percutaneous Through the skin.

Perforation, Fundal A (pathological or) surgical breaching of the integrity of the muscle at the top of the uterus.

Perforation A puncture or rupture of a hollow organ.

Perfusion Supply of blood to tissues.

Peri- Around.

Perianal Around the anus.

Pericarditis Inflammation of the outer lining of the heart.

Pericardium The potential space between the inner walls of the collapsed-balloon like covering of the heart.

Perichondritis Inflammation of the dense, irregular membrane around cartilage.

Pericolic Located alongside the large bowel.

Perihilar In the region of the hilum.

Perinatal In the period immediately before and shortly after birth.

Perineoplasty Repair of the perineum, the skin between genitals and anus.

Perineum The skin between genitals and anus.

Perioral Around the mouth.

Peripheral Nerve Trunk of nerve fibres outside the brain and spinal cord.

Peripheral Angiogram Radiological imaging of a bloodvessel away from the central core of the body, after the injection of a dye opaque to xrays.

Peripheral Vascular Disease Pathological narrowing of arteries supplying oxygenated blood to the limbs.

Peripheral Away from the centre of the body or an organ.

Perirectal Around the rectum.

Peritoneal Cavity The (normally potential) space within the peritoneum.

Peritoneum, Visceral or Splanchnic The part of the collapsed-balloon like lining of the abdominal and pelvic cavities which covers the organs contained therein, the spinal column, back of the bony pelvis, and attached muscles.

Peritoneum, Parietal The part of the collapsed-balloon like lining of the abdominal and pelvic cavities which covers the back of the abdominal wall.

Peritoneum The collapsed-balloon like inner lining of the abdomen or pelvis.

Peritonitis Inflammation of the collapsed-balloon like inner lining of the abdomen or pelvis.

Peripartum Around childbirth. 

Periumbilical Around the navel.

Perivascular Around blood-vessels.

Peroneal Relating to the fibula, the outer side of the leg, or the structures located there.

Peroneal Nerve Palsy(Common) Damage to the peroneal nerve, cause footdrop and a characteristic pattern of disturbed sensation on the upper surface of the foot.

Pfannenstiel Incision A horizontal curved surgical incision at the lower boundary of the abdomen, immediately above the pubic bones.

pH A measure of acidity.

Phalanx Bone of a finger or toe.

Pharynx Expanded tube joining mouth/nose and gullet.

Phenobarbital A barbiturate medication having sedative and anti-epileptic properties.

Philadelphia Chromasome Tiny abnormal chromosome usually formed by a rearrangement of chromosomes 9 and 22, and commonly found in chronic myelogenous leukemia.

Philtrum The vertical groove or dimple in the upper lip.

Phlebotomy The removal of blood from a vein for diagnostic or therapeutic purposes.

Phototherapy The use of light rays to treat disease, commonly to chemically change the potentially harmful yellow pigment bilirubin in the skin to harmless products.

Piriformis Syndrome Pain in the buttock and distribution of the sciatic nerve, caused by entrapment of the nerve by the piriformis muscle during passage of the nerve through the sciatic notch of the (bony) pelvis.

Placenta Previa, Marginal Low-lying placenta which encroaches on, but does not cover, the internal os, the exit of the uterus at the upper end of the cervix.

Placenta Previa Low-lying placenta which covers the internal os, the exit of the uterus at the upper end of the cervix.

Placenta Accreta Pathological embedding of a major or minor section of the placenta in the muscle of the uterus; the condition usually results in emergency hysterectomy.

Placental Insufficiency Pathological failure of adequate nutrition/oxygenation by the placenta.

Plasma Protein-rich, cell-free, blood.

Platelets Microscopic particles in the blood which stick to one another as part of the mechanism of clotting.

Pleura The collapsed-balloon like outer lining of the lung and the inner lining of the ribcage.

Pleural cavity The potential space between the outer lining of the lung and the inner lining of the ribcage.

Pleural effusion Fluid accumulation in the potential space between the outer lining of the lung and the inner lining of the ribcage.

Pleuritic Related to the lining of the lungs and chest cavity; when describing pain, meaning that the pain is increased with deep breathing.

Pneumatic Dilator Balloon-like surgical device for increasing the internal diameter of a tubular organ or orifice.

Pneumatosis Pathological accumulation of air in a tissue.

Pneumocystis A variety of micro-organism harmful when immune competence is compromised.

Pneumonia, Basal Infection of the lower segments of the lung.

Pneumonia, Community-Acquired Infection of the lung contracted outside of hospital or other institution, and not associated with other risk factors such as intravenous drug usage.

Pneumonia, Chronic Infection of the lung which is slow to resolve or heal, particularly caused by viruses or other micro-organisms not responsive to the common antibiotics.

Pneumonia Infection of the lung.

Pneumoperitoneum Presence in the peritoneal cavity of air, either pathologically caused or introduced for diagnostic or surgical purposes.

Pneumothorax Pathological presence of air in the potential space between the membrane lining the outside of the lung and that lining the inside of the ribcage.

Pole, of Kidney The upper or lower end.

Pollux Thumb.

Polycystic Ovary Syndrome (PCO) The fully developed condition comprises hairiness, obesity, menstrual abnormalities, infertility and lumpy enlargement of the ovaries.

Polycythemia A pathological increase in the concentration of Red Blood Cells in the blood.

Polydypsia Increased fluid intake because of pathologically excessive thirst, in this case because of polyuria.

Polyp Mass of tissue which projects, on a broad or slender stalk, from a body surface.

Polypectomy Surgical removal of a polyp.

Polyuria Production of excessive amounts of urine, causing frequent urination and potentially dehydration.

Pons Part of the brainstem at the base of the brain.

Pontine Pertaining to the pons.

Poorly Differentiated (Carcinoma) Often indicates a high degree of malignancy, and therefore a poorer than average prognosis, but with carcinoma of the cervix this feature applies only to the so-called glassy cell type, which was not present.

Poorly Differentiated Referring to malignancy, not possessing histological characteristics of the originating tissues - usually a feature of pathological aggression, as in this case.

Popliteal Pulse An arterial pulse which can be felt behind the knee.

Popliteal Vein Main vessel draining waste products in blood from the (lower) leg, and running at the back of the knee.

Popliteal Artery Main vessel carrying oxygen-rich blood to the (lower) leg, and running at the back of the knee.

Port-A-Cath Catheter implanted permanently into a large-calibre main vein for the provision of Total Parenteral Nutrition.

Porta Hepatis A horizontal fisssure in the liver, containing blood and lymph vessels, nerves and the hepatic ducts.

Portal Surgical access point for an endoscopic instrument such as an arthroscope.

Positron Emission Tomography (PET) Imaging of differences in the metabolism of internal body tissues by computer synthesis of data generated by measuring the radiation of positrons from radioactive chemicals incorporated into natural biochemical substances administered to the patient.

Post- After.

Post-Term Pregnancy Beyond 42 (previously 41) completed weeks since the first day of the Last Menstrual Period.

Postcoital After vaginal sexual intercourse.

Posterior Horn Of a cartilage (meniscus) is the finger-like backward extension.

Posterior Leaflet The back flap (leaflet or cusp) of the mitral valve.

Posterior Position Position in which the fetal back faces the front of the mother's bony pelvis.

Posterior Triangle An anatomical area bounded in the front by the back border of the sternocleidomastoid (strap) muscle of the neck, in the back by the front border of the trapezius (shoulder) muscle, and at the base by the collarbone.

Posterior Tibial Artery The main artery in the back of the thigh carrying oxygen-rich blood to the (lower) leg: it becomes the popliteal artery at the back of the knee.

Posterior Tibial Pulse An arterial pulse which can be felt behind the inner prominence of the ankle.

Posterior Towards or at the back of.

Postmaturity Continuation of a pregnancy beyond 42 completed weeks since the Last Normal Menstrual Period (or 40 completed weeks since the estimated time of ovulation).

Postmenopausal Postmenopausal: After the menopause.

Postnasal At or from the back of the nose.

Postpartum Hemorrhage (PPH), Delayed Vaginal bleeding of more than 500ml more than 24 hours after childbirth.

Postpartum Hemorrhage (PPH), Immediate Vaginal bleeding of more than 500ml within 24 hours after childbirth.

Postpartum After delivery.

Potentials (Action) Waveforms depicting the electrical activity in an active muscle.

Pouch of Douglas The potential space between the back of the uterus and the front of the rectum, otherwise known as the Cul-De-Sac.

Prednisone A synthetic corticosteroid medication administered to reduce pathological inflammation of various kinds.

Pre-Eclampsia (PET) High Blood Pressure with proteinuria or edema or both, caused by current or recent pregnancy. 

Pregnancy, Ectopic Growth of an embryo/fetus outside the cavity of the uterus, usually in the fallopian tube or abdominal cavity.

Premature Rupture of Membranes Spontaneous breach in the amnion and chorion, releasing amniotic fluid or liquor, with or without the onset of labour, before 37 weeks gestation.

Premature, of Coronary Artery Disease Before age 50 years.

Premature Ventricular Contractions Heart irregularity due to random extra beats.

Premature Labour or Delivery Onset of labour or delivery/birth before 37 completed weeks since the last normal menstrual period of a pregnancy.

Prematurity The current terminology is Preterm.

Premenstrual Syndrome Cyclical worsening before, and improving after, menstruation of a combination of symptoms including painful breasts, nausea, headache, bowel habit change, personality change, fluid retention, anxiety, insomnia, poor concentration, depressed mood, appetite change, vomiting, acne, and palpitations.

Prenatal Before delivery/birth.

Preterm Delivered/born before 37 completed weeks since the last normal menstrual period of a pregnancy.

Priapism Permanent erection caused by a pathological condition.

Primary Repair Surgical correction of injury without an intervening stage.

Primary (Carcinoma) The site at which a cancer originates.

Primary (Anastomosis) Surgical joining between two hollow or tubular organs at the first operation.

Primigravid Strictly, pregnant for the first time but conventionally refers to the first successful pregnancy.

Proctitis Inflammation of the rectum.

Profunda Femoris Artery One of the two main branches of the femoral artery, carrying oxygen-rich blood to the muscles of the thigh.

Prolapse Pathological displacement downwards or outwards of an organ.

Proliferative, of Endometrium Having the microscopic appearance typical of the lining of the uterus during days between the end of menstruation and ovulation.

Prolonged Rupture of Membranes Greater than 24 hours between spontaneous or artificial breach in the amnion and chorion, releasing amniotic fluid or liquor, and the delivery of the fetus: its significance is an increasing liability to health- and life-threatening infection of the fetus, and to a lesser extent maternal infection.

Prostaglandin A hormone which, among other actions, stimulates uterine contraction.

Prosthesis Artificial device to replace or assist damaged or missing bodily parts.

Proteinuria The presence or amount of protein in a specimen of urine, usually signifying kidney disease.

Prothrombin Time The ratio between the time it takes a test sample of blood to clot after addition of optimal quantities of calcium and the natural clotting stimulator thromboplastin compared with the time for a standard containing a normal quantity of the clotting precursor fibrinogen, which is reduced by the anticoagulant Coumadin.

Proximal Towards the centre of the body.

Pseudo- False.

Pseudo-aneurysm A pulsating, circumscribed collection of blood in communication with the channel of an injured artery.

Pseudocyst An abnormal cavity without a membranous lining, containing fluid.

Pseudomembranous (Entero-)Colitis Inflammation of the colon accompanied by membrane-like material in the stools, as a result of overgrowth by the bowel germ clostridium difficile following the administration of broad-spectrum antibiotics.

Pseudoptosis Having the appearance of being prolapsed or fallen, but not being so.

Psoas Sign With the patient lying on the left side, (backward) extension of the right hip gives pain when the psoas muscle is overlain by an inflamed appendix.

Psychosomatic The production of physical illness or symptoms by emotional or psychological disturbance, with absent or limited awareness.

Pterion A + or H shaped join of 4 skull bones towards the front of the temple, overlying the origin of the middle cerebral artery deep in the brain.

Ptosis Drooping, of an eyelid in this instance.

Pubic Bone Paired component of the bony pelvis located centrally at the lower boundary of the abdomen, and forming the front (anterior) part of the pelvic inlet.

Pubis A paired bone forming the front of the bony pelvis.

Puerperium Medically (but not psychologically) defined as the 42 day period from childbirth to the return of the uterus to normal size.

Pulmonary Tuberculosis Infection of the lung(s) with the pathogenic micro-organism known as Mycobacterium tuberculosis.

Pulmonary Hypertension Pathologically raised pressure in the pulmonary arteries supplying oxygen-depleted blood to the lungs.

Pulmonary Embolism (PE) The passage of blood clot, originating in large veins, into the pulmonary arteries, the major blood vessels supplying oxygen-depleted blood to the lungs.

Pulmonary or Pulmonic (Valve) Stenosis Pathological narrowing of the heart valve which normally prevents backflow of oxygen-poor blood from the main pulmonary artery into the right ventricle.

Pulmonary Function Tests A standard set of investigations measuring the mechanical properties of the lungs.

Pulmonary Pertaining to the lung.

Pulse Rate The per minute heart-rate as measured at a pulse location, typically at the wrist.

Purpura Localised hemorrhage into the skin.

Purulent Like pus.

Pus Fluid containg dead cells and tissue products, liquified by enzymes produced by white blood cells.

Pyelonephritis Bacterial infection of the kidneys.

Pyloroplasty Form of drainage procedure in which the outlet of the stomach is modified surgically to encourage prompt emptying into the duodenum.

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