Human health and medicine

Plank (exercise)

Plank (exercise): isometric core hold keeping the body straight on forearms or hands; trains rectus abdominis, obliques, transversus abdominis; dosed in 20-second to 2-minute holds, two to four times weekly.

Planned Parenthood

Planned Parenthood (PPFA) is the largest U.S. nonprofit provider of sexual and reproductive health care and sex education, founded from Margaret Sanger's 1916 Brooklyn birth control clinic, with nearly 600 health centers, 2 million-plus patients, and major 2025 Medicaid funding battles.

Planning fallacy

Planning fallacy, named by Kahneman and Tversky in 1979, is the tendency to underestimate task time, cost, and risk while overestimating benefits; corrected by reference class forecasting using outcomes of similar past projects.

Plant-based diet

Plant-based diet: an eating pattern centered on plant foods with animal products reduced or excluded; term coined by T. Colin Campbell in the 1980s; linked to metabolic benefits but requires B12 supplementation.

Plantar fascia

Plantar fascia (plantar aponeurosis): dense fibrous tissue from heel to toes supporting the foot arch via the windlass mechanism; central, lateral, medial bands; source of plantar fasciitis, seen in about 10% of people.

Plantar fasciitis

Plantar fasciitis, also called plantar fasciopathy, is strain-related heel and arch pain worst with first steps after rest. Affects 1 in 10 people, peaks at 45-65, and about 90% of cases resolve within 12 months with conservative care.

Plantar reflex

Plantar reflex: sole-of-foot reflex; normal adults flex the big toe, while upgoing toe (Babinski sign, described 1896) indicates corticospinal tract dysfunction; insensitive but highly specific.

Plantar wart

Plantar wart (verruca plantaris): an HPV-caused wart (types 1, 2, 4) on the sole of the foot, with black vessel dots and mosaic clustering; treated with salicylic acid or cryotherapy, roughly equal in effectiveness.

Plaque brachytherapy

Plaque brachytherapy is a radiation therapy technique in which a radioactive plaque is sutured to the sclera to deliver a localized dose to an intraocular tumor, most often uveal melanoma.

Plaque psoriasis

Plaque psoriasis, also known as psoriasis vulgaris, is a chronic inflammatory skin disease causing red, scaly patches, accounting for 80% to 90% of psoriasis cases worldwide.

Plaque radiotherapy

Plaque radiotherapy is a brachytherapy technique in which a radioactive plaque is sutured to the sclera over an intraocular tumor, mainly to treat uveal melanoma.

Plasma cell leukemia

Plasma cell leukemia (PCL), primary or secondary, is a rare, aggressive plasma cell dyscrasia related to multiple myeloma, now defined by the IMWG as 5% or more circulating plasma cells in peripheral blood, with poor survival despite proteasome inhibitors and transplantation.

Plasma cell neoplasms

Plasma cell neoplasms are clonal plasma cell disorders ranging from MGUS through smoldering myeloma to multiple myeloma, in which abnormal plasma cells form tumors in bone or soft tissue.

Plasma exchange

Plasma exchange, also called therapeutic plasma exchange or plasmapheresis, is a procedure that removes a patient's plasma and replaces it with albumin or donor plasma.

Plasma osmolality

Plasma osmolality (serum osmolality) is the concentration of osmotically active particles in plasma, normally 275-295 mOsm/kg, measured by freezing point osmometry; the osmolal gap screens for toxic alcohols.

Plasma protein binding

Plasma protein binding (PPB): reversible binding of drugs to plasma proteins, mainly albumin and alpha-1-acid glycoprotein. Only the unbound fraction is pharmacologically active; measured by equilibrium dialysis or ultrafiltration; displacement interactions are rarely clinically significant.

Plasma Skin Regeneration

Plasma skin regeneration (PSR, Portrait, NeoGen): non-laser skin resurfacing using millisecond pulses of nitrogen plasma, 1-4 J, FDA cleared 2006 for wrinkles, actinic keratoses, and acne scars.

Plasma Volume

Plasma volume is the cell-free intravascular portion of blood, part of the extracellular fluid compartment. Measured by indicator dilution with Evans blue, indocyanine green, or radio-iodinated albumin; hematocrit-based estimates are unreliable.

Oct 20, 2026

Plasmablastic lymphoma

Plasmablastic lymphoma (PBL) is a rare, very aggressive CD20-negative large B-cell non-Hodgkin lymphoma, first described in 1997 in the oral cavity of HIV-infected patients, marked by a plasma cell immunophenotype, EBV association, and frequent MYC rearrangements.

Plasmacytoma

Plasmacytoma, also called solitary plasmacytoma (SBP or EMP), is a rare single-site clonal plasma cell tumor with under 10% marrow involvement, treated mainly with 40-50 Gy radiotherapy and carrying a 14-38% three-year risk of progression to multiple myeloma.

Plasmapheresis

Plasmapheresis (therapeutic plasma exchange, TPE): extracorporeal separation and removal of blood plasma, by centrifugation or membrane filtration, to treat antibody-mediated diseases; ASFA categories I–IV guide use, typically 1–1.5 plasma volumes over 5–6 sessions.

Plastic and reconstructive surgery

Plastic and Reconstructive Surgery (PRS) is the monthly peer-reviewed official journal of the American Society of Plastic Surgeons, published by Lippincott Williams & Wilkins since 1946, with open-access companion PRS Global Open (2013).

Plastic bronchitis

Plastic bronchitis (PB), also called cast bronchitis or Hoffman bronchitis, is a rare disorder in which branching bronchial casts obstruct airways. Subtypes are lymphatic (post-Fontan) and eosinophilic; treatment includes lymphatic embolization.

Plastic surgery

Plastic surgery: surgical specialty restoring or altering body form and function, spanning reconstructive and cosmetic work. Founded as a specialty by Harold Gillies in WWI at Sidcup; tubed pedicle flaps; now millions of procedures yearly.

Plastination

Plastination, invented by Gunther von Hagens in 1977 at Heidelberg, preserves anatomical specimens by replacing water and fat with curable polymers via vacuum impregnation, yielding dry, odorless, durable teaching and exhibition specimens (Body Worlds).

Plate fixation

Plate fixation is a surgical technique for treating fractures that uses a metal plate and screws to provide absolute or relative stability for bone healing.

Plateau iris syndrome

Plateau iris syndrome (PIS): angle closure persisting after patent laser iridotomy, caused by an anteriorly positioned ciliary body pushing the iris root into the trabecular meshwork; distinct from plateau iris configuration, treated with iridoplasty.