Human health and medicine

Pigeon toe

Pigeon toe (intoeing) is a common childhood gait pattern with feet turned inward, caused by metatarsus adductus, internal tibial torsion, or femoral anteversion; it usually self-corrects by age 8 without treatment.

Pigmentary open-angle glaucoma

Pigmentary open-angle glaucoma (pigmentary glaucoma, PG): secondary open-angle glaucoma from pigment dispersion syndrome, affecting young myopic men, with higher surgery rates and LTP/MIGS failure than POAG.

Pigmentation

Pigmentation: coloration or discoloration of tissue by a pigment, chiefly melanin in human skin, hair, and eyes. Covers melanin biology, hyper- and hypopigmentation disorders, measurement scales, and device accuracy effects.

Pigmented villonodular synovitis

Pigmented villonodular synovitis (PVNS), now called tenosynovial giant cell tumor, is a rare benign but locally aggressive proliferation of the joint lining, most often affecting the knee.

PIHRK'D trial

PIHRK'D (NCT06080425) is a completed ADA-funded feasibility trial by UTMB Galveston testing family-based medical nutrition therapy and Dining with Diabetes for 48 rural Kentuckians with type 2 diabetes and overweight or obesity.

PII A trial

The PII A trial, known as PARTNER 2A, was a randomized trial comparing transcatheter (TAVR) with surgical aortic valve replacement in 2,032 intermediate-risk patients with severe aortic stenosis.

Pikachurin

Pikachurin (EGFLAM) is an extracellular matrix protein of the photoreceptor ribbon synapse cleft, identified in 2008, that binds alpha-dystroglycan via LG2-LG3 domains and GPR179, aligning bipolar dendrites; its loss disrupts retinal signaling.

Pilates

Pilates, originally Contrology, is an exercise system created by Joseph Pilates (1883–1967) using mat and apparatus work built on six principles; evidence supports benefits for chronic low back pain, flexibility, and balance.

Pili bifurcati

Pili bifurcati (ORPHA:720, ICD-10 L67.8) is a rare hair shaft dysplasia with segmental shaft duplication: two cuticle-covered branches fuse back into one shaft, caused by transient papilla-tip duplication during anagen.

Pili gemini

Pili gemini (pili multigemini), ORPHA:79492, is a rare hair follicle abnormality where the follicular papilla splits in anagen so multiple hair shafts emerge from one follicular opening, mostly in men's beards; ICD-10 L67.8.

Pili torti

Pili torti (twisted hair) is a rare hair shaft disorder with flattened shafts twisted 180 degrees, causing brittle, spangled, easily broken hair; isolated, syndromic (Menkes, Bjornstad), or acquired.

Pilocarpine

Pilocarpine, a plant-derived muscarinic cholinergic agonist introduced to ophthalmology in 1876, lowers intraocular pressure in glaucoma and, in low concentrations (Vuity 1.25%, Qlosi 0.4%), treats presbyopia; limited today by miosis, blurred vision, and frequent dosing.

Pilocytic astrocytoma

Pilocytic astrocytoma, also known as juvenile pilocytic astrocytoma, is a slow-growing grade 1 glioma, the most common brain tumor in children, with 90% ten-year survival.

Pilomatrix carcinoma

Pilomatrix carcinoma, also called malignant pilomatricoma, is a rare malignant skin tumor of hair follicle cells, usually a firm nodule on the head or neck of older adults.

Pilomatrixoma

Pilomatrixoma (calcifying epithelioma of Malherbe, pilomatricoma) is a benign hair follicle matrix tumor, common in children on the head and neck, linked to CTNNB1/Wnt mutations, treated by excision with low recurrence.

Pilonidal disease

Pilonidal disease, also called pilonidal sinus or jeep disease, is an acquired infection of the natal cleft caused by penetrating loose hairs, affecting young adults; treated by drainage, off-midline flap surgery, and hair removal.

Pilosebaceous hamartoma

Pilosebaceous hamartoma (ICD-11 LC01) is a benign, tumor-like malformation of the hair follicle and sebaceous gland. Subtypes include basaloid follicular hamartoma and folliculosebaceous cystic hamartoma, first described by Kimura in 1991.

Pimavanserin

Pimavanserin (Nuplazid), a selective 5-HT2A inverse agonist by ACADIA Pharmaceuticals, is the first FDA-approved drug (April 2016) for hallucinations and delusions of Parkinson's disease psychosis, distinct from dopamine-blocking antipsychotics.

Pimecrolimus

Pimecrolimus, marketed as Elidel, is a 1% topical calcineurin inhibitor cream approved in the United States in 2001 for mild to moderate atopic dermatitis in patients aged 2 and older.

Pimicotinib

Pimicotinib (匹米替尼, ABSK021) is Abbisko Therapeutics' oral CSF-1R inhibitor for unresectable tenosynovial giant cell tumor; MANEUVER phase 3 showed 54% ORR versus 3.2% placebo, and China's NMPA approved it in December 2025.

Pimple

A pimple, also called a zit, is a small inflamed skin lesion that forms when a pore clogs with oil, bacteria, and dead skin cells; pimples are the lesions of acne.

Pinacidil anhydrous

Pinacidil anhydrous (UNII BB4UGO5K0D) is the active-moiety form of pinacidil, a racemic cyanoguanidine KATP channel opener (SUR2A/SUR2B) that vasodilates arterioles to treat hypertension; FDA-discontinued, dose-limited by edema and tachycardia.

Pinaverium

Pinaverium (pinaverium bromide, Dicetel, Pinverin) is a GI-selective quaternary ammonium calcium channel blocker antispasmodic, poorly absorbed orally, used mainly for irritable bowel syndrome symptoms.

Pinch Strength

Pinch strength: force exerted by the index finger and thumb, measured by pinch gauge as maximum voluntary contraction. Types are tip, three-jaw chuck, and lateral pinch; reliability ICC > 0.75-0.90, correlated with grip strength (r 0.72-0.92).

Pinda Taila

Pinda Taila (Pinda Thailam) is a classical Ayurvedic cooling medicated oil, AFI-listed, made with beeswax, Manjishtha, Sarjarasa, and Sariva in sesame oil, applied externally for Vatarakta (gout) pain and burning sensations.

Pineal gland

Pineal gland (epiphysis, conarium): a 100-150 mg midline neuroendocrine organ in the brain that secretes melatonin at night under sympathetic control from the SCN, timing circadian and seasonal physiology.

Pineal parenchymal tumor of intermediate differentiation

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare WHO grade 2 or 3 brain tumor arising from the pineal gland, intermediate between pineocytoma and pineoblastoma.

Sep 29, 2026

Pinealectomy

Pinealectomy is the surgical removal of the entire pineal gland, which secretes melatonin. It is an uncommon clinical operation for pineal tumors and a standard research technique for studying circadian rhythms.

Pineoblastoma

Pineoblastoma is a fast-growing, CNS WHO grade 4 malignant embryonal brain tumor of the pineal gland, mainly in young children. Four molecular subtypes (miRNA-altered, MYC/FOXR2, RB1) determine prognosis; treatment combines surgery, radiation, and chemotherapy.