papilledema Swelling of the head of the optic nerve, a sign of increased pressure within the skull. The optic nerve head is the area where the optic nerve (the nerve that carries information from the retina to the brain) enters the eyeball. Papilledema is diagnosed through use of an ophthalmoscope. The optic nerve head is…
papilloma A small solid benign tumor with a clear-cut border that projects above the surrounding tissue. A raised wart is an example of a papilloma.
papilloma, intraductal See intraductal papilloma.
papillomatosis A disorder that is characterized by the growth of numerous papillomas (warts). For example, laryngeal papillomatosis is the presence of multiple papillomas on the vocal cords.
papular Referring to papules.
papule A solid, rounded growth that is elevated from the skin. A papule is usually less than 1 cm (0.5 in.) across. Papules may open when scratched and become crusty and infected.
para- A prefix with many meanings, including alongside, beside, near, resembling, beyond, apart from, and abnormal, as in parathyroid glands (glands that are adjacent to the thyroid) and paraumbilical (alongside the umbilicus).
paracentesis The removal of fluid from a body cavity via a needle, a trocar, a cannula, or another hollow instrument. A paracentesis may be used for diagnosis or treatment, as, for example, in ascites, where there is free fluid in the abdominal (peritoneal) cavity. If the cause of the ascites is uncertain, diagnostic paracentesis is…
paracentric chromosome inversion See chromosome inversion, pericentric.
paracetamol See acetaminophen.
paraffin dip A treatment for the symptoms of joint and muscle conditions, such as arthritis, that involves applying melted mineral wax derived from petroleum to a body area. Paraffin dips can be especially helpful in relieving the pain and stiffness of arthritis involving the small joints of the hands. The hands are repeatedly dipped into…
paragonimiasis Infection with the trematode (parasitic worm) Paragonimus, most commonly with Paragonimus westermani, the oriental lung fluke. Human infection with P. westermani occurs by eating inadequately cooked or pickled crab or crayfish that harbor the parasite. The parasites penetrate through the intestinal wall into the peritoneal cavity, then through the abdominal wall and diaphragm into…