Medical terms - Letter P (page 23) | MedicalVocabulary.org

Pressure wound

See: Pressure sore
Pressure, intraocular

The pressure created by the continual renewal of fluids within the eye. The intraocular pressure is increased in glaucoma. In acute angle-closure glaucoma, the intraocular pressure rises because the canal into which the…
Pressure, low blood

Any blood pressure that is below the normal expected for an individual in a given environment. Low blood pressure is also referred to as hypotension. Low blood pressure is a relative term because the blood pressure…
Prevalence

The proportion of individuals in a population having a disease. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time
Preventive medicine

Medicine designed to avert and avoid disease. Screening for hypertension and treating it before it causes disease is good preventive medicine. Preventive medicine is a proactive approach
Priapism

Abnormally persistent erection of the penis in the absence of sexual desire. Priapism can occur in persons with sickle cell anemia. Named after Priapus, the Greek and Roman god of procreation, whose nude statues were…
Primary

First or foremost in time or development. The primary teeth (the baby teeth) are those that come first. Primary may also refer to symptoms or a disease to which others are secondary. A primary tumor is one that is at…
Primary amebic meningoencephalitis

A rare, but fatal infection of the central nervous system caused by Naegleria fowleri, an ameba that inhabits freshwater lakes, rivers and hot springs. The disease results when ameba-contaminated water incidentally…
Primary amenorrhea

Absence of menstruation. Amenorrhea is conventionally divided into primary and secondary amenorrhea. With primary amenorrhea, menstruation never takes place. It fails to occur at puberty. With secondary amenorrhea…
Primary amyloidosis

Amyloidosis: A disorder of plasma cells (special white blood cells that produce antibodies), this is one of a group of diseases (called amyloidosis) in which protein deposits (amyloid) accumulate in one or more organ…
Primary atelectasis

Failure of the lung to expand fully at birth. In contrast to secondary atelectasis in which there is partial or complete collapse of a lung that once had expanded, as may happen after chest surgery
Primary biliary cirrhosis (PBC)

A liver disease caused by an abnormality of the immune system. Small bile ducts within the liver become inflamed and obliterated. Backup of bile causes intense skin itching and yellowing of the skin (jaundice). Lack of…
Primary care

The 'medical home' for a patient, ideally providing continuity and integration of health care. All family physicians and most pediatricians and internists are in primary care. The aims of primary care are to provide the…
Primary care provider

In insurance parlance, a physician chosen by or assigned to a patient, who both provides primary care and acts as a gatekeeper to control access to other medical services
Primary cataract

See: Cataract, primary
Primary ciliary dyskinesia

The immotile cilia syndrome, a condition in which poorly functioning cilia (hairlike projections from cells) in the respiratory tract contribute to retention of secretions and recurrent infection. The condition is…
Primary dentition

The set of 20 first (deciduous) teeth. The primary dentition is as opposed to the secondary (permanent) dentition. At birth, both sets of dentition are evident by X-ray.
Primary HIV infection

The first few months after infection with HIV (the human immunodeficiency virus). During primary HIV infection, seroconversion occurs -- the appearance of detectable antibodies to HIV in the blood. It normally takes…
Primary immunodeficiency disease

A disorder caused by an inherited flaw in the immune system that increases the susceptibility to infections. Primary immunodeficiency diseases are unlike secondary or acquired immune deficiency diseases, which are…
Primary liver cancer, adult

A tumor in which the cancer starts during adulthood in cells in the liver. Also called hepatocellular carcinoma. Primary liver cancer is different from cancer that has metastasized (spread) from another place in the…
Primary progressive aphasia

An atypical dementia characterized by a relentless dissolution of language with memory relatively preserved. The diagnosis of primary progressive aphasia is based on the presence of a progressive disorder of language…
Primary sclerosing cholangitis

Primary sclerosing cholangitis: A chronic disorder of the liver in which the ducts carrying bile from the liver to the intestine, and often the ducts carrying bile within the liver, become inflamed, thickened, scarred…
Primary teeth

The first teeth which are shed and replaced by permanent teeth. The first primary tooth comes in at about 6 months of age and the 20th and last primary tooth erupts at around 2 1/2 years of age. The primary teeth are…
Primary tumor

A tumor that is at the original site where it first arose. For example, a primary brain tumor is one that arose in the brain as opposed to one that arose elsewhere and metastasized (spread) to the brain. The original…
Primitive neuroectodermal tumor

One of a remarkable group of tumors that originate in cells from the primitive neural crest and share the same reciprocal translocation between chromosomes 11 and 22 and the same patterns of biochemical and oncogene…
Primordia

See: Primordium
Primordium

In embryology, organ or tissue in its earliest recognizable stage of development. As, for example, the thyroid primordium. The plural is primordia. Borrowed directly from the Latin primordium (to begin), derived from…
Primum non nocere

The Latin words for medical slogan 'First do no harm,' a fundamental medical precept of Hippocrates (ca. 460-ca.377 B.C.)
Principal investigator

In biomedical research, the person who directs a research project or program. The principal investigator (the PI) usually writes and submits the grant application, oversees the scientific and technical aspects of the…
Principal joints of the body

>Acromioclavicular >Ankle (tibia-fibula and talus) >Atlas and axis >Atlas and occipital >Calcaneocuboid >Carpometacarpal >Elbow (humerus, radius, and ulna) >Femur and tibia >Hip bone and femur >Humerus and ulna…
Prinzmetal angina

See: Angina, Prinzmetal
Prion

A disease-causing agent that is neither bacterial nor fungal nor viral and contains no genetic material. A prion is a protein that occurs normally in a harmless form. By folding into an aberrant shape, the normal prion…
Prion dementia

See: Gerstmann-Straussler-Scheinker syndrome
Prion disease

A disease due to a prion, a proteinaceous infectious particle that lacks nucleic acids. Prions are composed largely, if not entirely, of an altered formal (an abnormal isoform) of a normal cellular protein. The known…
Prior approval

See: Prior authorization
Prior authorization

In pharmacy, a cost-containment procedure that requires a prescriber to obtain permission to prescibe a medication prior to prescribing it. Also called prior approval
Private mutation

A rare mutation found usually only in a single family or a small population. It is like a privately printed book
PRK (photorefractive keratectomy)

A kind of laser eye surgery designed to change the shape of the cornea to eliminate (or reduce) the need for glasses and contact lenses. The laser is used to remove the outer layer of the cornea and flatten the cornea…
PRKAR1A

Stands for Protein Kinase A Regulatory subunit 1-alpha. A multiple neoplasia syndrome called type I Carney complex is due to mutation of the PRKAR1A gene, which is on chromosome 17q23-q24. See also: Carney complex
Pro

Proline. See also: Amino acid symbols
Pro time

The pro time (or, more properly, the prothrombin time) is a test of the integrity of part of the clotting scheme. The prothrombin time is also commonly used as a method of monitoring the accuracy of blood thinning…
Pro-

The likelihood that something will happen. For example, a probability of less than .05 indicates that the probability of something occurring by chance alone is less than 5 in 100, or 5 percent. This level of probability…
Probability

The likelihood that something will happen. For example, a probability of less than .05 indicates that the probability of something occurring by chance alone is less than 5 in 100, or 5 percent. This level of probability…
Proband

The family member through whom a family's medical history comes to light. For example, a proband might be a baby with Down syndrome. The proband may also be called the index case, propositus (if male), or proposita (if…
Probe

(1) In surgery, a probe is a slender flexible rod with a blunt end used to explore, for example, an opening to see where it goes. (2) In molecular genetics, a probe is a labeled bit of DNA or RNA used to find its…
Probiotic

A microbe that protects its host and prevents disease. The best-known probiotic is Lactobacillus acidophilus, which is found in yogurt, acidophilus milk, and supplements. Probiotics counter the decimation of helpful…
PROC

Protein C
Procedure, Whipple

See: Whipple procedure
Process

In anatomy, a process is a projection from a structure. The process of the mandible is the part of the lower jaw that projects forward. In a more general sense, a process is a series of actions or events that are part…
Proclivity

An inclination or predisposition toward something, especially a strong inherent inclination toward something objectionable. For example, a patient might be said to have a proclivity toward alcohol