Medical terms - Letter P (page 6) | MedicalVocabulary.org

Parvovirus infection

Infection with one of a family of small single-stranded DNA viruses. (Parvovirus means small virus, from the Latin parvus, small.) One type, parvovirus B19, infects only humans. There are also animal parvoviruses, but…
PAS

1. Physician-assisted suicide. 2. Personal alert system (an alarm system for an elderly or infirm person). 3. Periodic acid-Schiff (a stain used to detect carbohydrates in tissue).
Passage, nasal

The walls of the nasal passages are coated with respiratory mucous membranes which contain innumerable tiny hair-like cells that act to move waves of mucus toward the throat. Dust, bacteria, and other particles inhaled…
Passive exercise

Movement of the body, usually of the limbs, without effort by the patient. The patient is passive
Passive immunity

Immunity produced by the transfer to one person of antibodies that were produced by another person. Protection from passive immunity diminishes in a relatively short time, usually a few weeks or months. For example…
Passive smoking

The inhaling of environmental tobacco smoke (ETS) by someone who is not smoking. See: ETS
Passive-aggressive

Pertaining to behavior in which feelings of aggression are expressed in passive ways as, for example, by stubbornness, sullenness, procrastination, or intentional inefficiency. The term passive-aggressive behavior was…
Passive-aggressive personality disorder

A personality disorder characterized by passive-aggressive behavior. Passive-aggressive personality disorder is no longer recognized as a diagnosis by the American Psychiatric Association
Pasteur Institute

A non-profit private foundation which contributes to the prevention and treatment of disease, primarily infectious diseases, through research, education, and public health activities. The Pasteur Institute was…
Pasteur, Louis

French chemist and biologist (1822-1895) who invented pasteurization, developed the germ theory, founded the field of bacteriology and created the first vaccines against anthrax and rabies. Pasteur's impact upon…
Pasteurization

A method of treating food by heating it to a certain point to kill pathogenic (disease-causing) organisms but not harm the flavor or quality of the food. Milk is pasteurized by heating it to about 145°F (63°C) for 30…
PAT

Paroxysmal atrial tachycardia
Patau syndrome (trisomy 13 syndrome)

A syndrome characterized by multiple malformations, commonly including scalp defects, hemangiomas (blood vessel malformations) of the face and nape of the neck, cleft lip and palate, malformations of the heart and…
Patella

The kneecap by another name, the patella is the small bone that is in the front of the knee. The patella is a sesamoid bone, a little bone (sesamoid = like a sesame seed) that is embedded in a joint capsule or tendon…
Patellar

Pertaining to the patella, the kneecap by another name, the familiar small bone planted in the front of the knee. Patella is a Latin word that referred to a 'small pan, dish or plate.' As a saucer, the patella is quite…
Patellar ligament

See: Patellar tendon
Patellar reflex

See: Knee jerk
Patellar tendon

A tendon that extends down from the quadriceps muscle in the thigh to incorporate the patella (the kneecap) and attach it to the tibia (the shinbone), providing extension at the knee joint. The patellar tendon is also…
Patellar tendon reflex

See: Knee jerk
Patellar tendonitis

A common injury to the patellar tendon. Also called patellar tendonopathy or jumper's knee because it often occurs in basketball and volleyball and other high impact sports. There may be sudden aching and pain with…
Patellar tendonopathy

See: Patellar tendonitis
Patellectomy

An operation to remove the patella
Patellofemoral joint

One of the knee joints. The knee has three parts. The thigh bone (femur) meets the large shin bone (tibia) forming the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap…
Patellofemoral syndrome (PFS)

Patellofemoral syndrome (PFS): The commonest cause of chronic knee pain, PFS characteristically causes vague discomfort of the inner knee area, aggravated by activity (running, jumping, climbing or descending stairs) or…
Patent (adjective)

Open, unobstructed, affording free passage. Thus, for example, the bowel may be patent (as opposed to obstructed). Pronounced 'pa-tent' with the accent on the first syllable.
Patent (noun)

A device giving exclusive control and possession. Before the commercialization of biomedical inventions, the word 'patent' in this sense had no place in a medical dictionary. Now the patent is the foundation of the…
Patent ductus

Failure of the ductus arteriosus, which functions in fetal life as an arterial shunt, to close on schedule at or shortly after birth. When the shunt remains open, it is said to be patent. See: Patent ductus arteriosus
Patent ductus arteriosus

Failure for the ductus arteriosus, an arterial shunt in fetal life, to close on schedule. Before birth, blood pumped from the heart through the pulmonary artery toward the lungs is shunted into the aorta. This arterial…
Patent urachus

A birth defect involving the urachus, a canal connecting the bladder of the fetus with the allantois, a structure that contributes to the formation of the umbilical cord. The lumen (inside) of the urachus is normally…
Paterfamilias

The male head of the family; the father figure. Paterfamilias is the Latin for father of the household. It is compounded from pater (father) + familias, which comes from familia (household), from famulus (servant…
Paternal

1. Pertaining to the father as, for example, a paternal age effect.2. Related through the father as, for example, the paternal grandparents.3. Inherited from the father as, for example, the paternal X chromosome.
Paternal age

The age of the father at the time he conceives a child. The present mean (average) paternal age is 27 years in the US population. Advanced paternal age is clearly associated with an increased risk of new mutations, a…
Paterson-Kelly syndrome

See: Plummer-Vinson syndrome
Patho-

Pathology, with emphasis on the pathophysiological and pathogenetic mechanisms underlying human disease.
Pathobiology

Pathology, with emphasis on the pathophysiological and pathogenetic mechanisms underlying human disease
Pathogen

An agent of disease. A disease producer. The term pathogen most commonly is used to refer to infectious organisms. These include bacteria (such as staph), viruses (such as HIV), and fungi (such as yeast). Less commonly…
Pathogen inactivation

A process designed to eliminate most pathogens -- viruses, bacteria and fungi -- from water, air or donated blood. Sewage purification systems depend upon pathogen inactivation to purify water to the extent it may…
Pathogen, special

See: Special pathogen
Pathogenesis

The development of a disease. The origin of a disease and the chain of events leading to that disease
Pathogenetic

Pertaining to the pathogenesis of a disease, to exactly how it develops and the precise chain of events leading to it
Pathogenic

Causing disease or capable of doing it. Pathogenic bacteria are disease-causing bacteria. For example, pathogenic E. coli are E. coli that are not innocuous (like most E. coli) but can make a person ill and even kill…
Pathogenicity island

The genetic element, the 'island of evil', within the genome of an organism that is responsible for its capacity to cause disease (its pathogenicity). The virulence of the organism is modulated by genes harbored on this…
Pathognomonic

A sign or symptom that is so characteristic of a disease that it makes the diagnosis. For example, Koplik's spots (on the buccal mucosa opposite the lst and 2nd upper molars) are pathognomonic of measles. The word…
Pathologic

1. Indicative of or caused by disease, as in a pathologic fracture, pathologic tissue, or pathologic process. 2. Pertaining to pathology, the branch of medicine that studies disease and especially the essential nature…
Pathologic fracture

A bone broken, not by trauma alone, but so weakened by disease as to break with abnormal ease. Pathologic fractures are characteristic of metastatic lung and breast cancer and myeloma
Pathological hoarding

Excessive hoarding of material goods, a condition that affects up to 40% of people with obsessive compulsive disorder (OCD). Excessive hoarders, who fill their houses with accumulations of junk, usually newspapers, bags…
Pathologist

A doctor who identifies diseases by studying cells and tissues under a microscope
Pathologist, speech-language

See: Speech-language pathologist
Pathology

The study of disease. Pathology has been defined as 'that branch of medicine which treats of the essential nature of disease.' The word 'pathology' comes from the Greek words 'pathos' meaning 'disease' and 'logos'…
Pathophysiology

Deranged function in an individual or an organ that is due to a disease. A pathophysiologic alteration is a change in function as distinguished from a structural defect.