Human health and medicine

Hard palate

Hard palate: bony anterior two thirds of the mouth's roof, formed by maxillary palatine processes and palatine bone horizontal plates, separating oral and nasal cavities; develops from the secondary palate between weeks 6 and 12.

Harderoporphyria

Harderoporphyria (HARPO), a rare autosomal recessive erythropoietic variant of hereditary coproporphyria caused by biallelic CPOX mutations such as K404E, presents neonatally with hemolytic anemia, jaundice, and massive fecal harderoporphyrin excretion.

Hardikar syndrome

Hardikar syndrome (HDKR, cholestasis-pigmentary retinopathy-cleft palate syndrome) is an ultra-rare X-linked dominant MED12 loss-of-function disorder affecting females, with cleft lip/palate, cat's-paw retinopathy, hepatobiliary disease, and normal cognition.

Hardware Removal

Hardware removal (implant removal, metalwork removal) is the surgical extraction of orthopedic plates, screws, and nails after fracture fixation, done for pain, infection, or broken hardware; evidence does not support routine removal of asymptomatic implants such as syndesmotic screws.

Hardy W. Trolander

Hardy Wilcox Trolander (1921–2013) was an American engineer who co-founded the Yellow Springs Instrument Company in Ohio and led it for nearly 40 years, commercializing the world's first biosensor.

Haridra khanda

Haridra khanda (Haridrā Khaṇḍa), also Haridra Khandam, is a classical Ayurvedic granular formulation with turmeric (Curcuma longa), ghee, milk, sugar, spices, and Lauha bhasma, used for urticaria and allergic skin disorders, dose 6 g.

Haritala sodhana

Haritala sodhana (Haratala Shodhana) is the Ayurvedic purification of orpiment (arsenic trisulfide, As2S3), an Uparasa and Dhatuja Visha mineral, by Swedana or Bhavana in media such as Kushmanda Swarasa and Churnodaka, yielding Shodhita Haratala for Rasamanikya.

Harlequin syndrome

Harlequin syndrome, a rare dysautonomic disorder first described by Lance et al in 1988, causes unilateral facial flushing and sweating with midline demarcation from contralateral anhidrosis, usually idiopathic or from sympathetic fiber disruption.

Harlequin-type ichthyosis

Harlequin-type ichthyosis (harlequin ichthyosis, harlequin fetus, ARCI4B) is a severe autosomal recessive congenital skin disorder caused by ABCA12 mutations, producing armor-like scale plates, ectropion, eclabium, and roughly 50% neonatal survival with retinoid therapy.

Harmonic imaging

Harmonic imaging is an ultrasound method that forms diagnostic images from harmonic frequencies generated as the pulse travels through tissue, giving less noise and better contrast.

Harmonic motion imaging

Harmonic motion imaging (HMI) is an ultrasound-based elasticity imaging technique that assesses tissue stiffness by inducing oscillations with a focused ultrasound transducer and tracking the resulting displacement.

Harold J. Fallon

Harold J. Fallon (1931–2018) was an American hepatologist who chaired medicine at the Medical College of Virginia and led the landmark corticosteroid trial for alcoholic hepatitis.

HARP (algorithm)

HARP (harmonic phase) MRI algorithm, by Osman and Prince, Johns Hopkins, 1999: rapid analysis of SPAMM-tagged cardiac MR images using invariant harmonic phase to track myocardial motion and strain; basis of Diagnosoft HARP software.

Oct 15, 2026

Harpoon TSD-5

The Harpoon TSD-5 is a transapical, beating-heart mitral valve repair system by Harpoon Medical that anchors artificial chordae to a prolapsed leaflet under echo guidance.

Harringtonine

Harringtonine, chiefly homoharringtonine (高三尖杉酯碱, omacetaxine mepesuccinate), is a Cephalotaxus alkaloid inhibiting protein synthesis elongation, used in China since 1977 for AML and FDA-approved in 2012 for CML.

Harris hip score

The Harris hip score is a clinical rating scale scoring pain, function, range of motion, and deformity after hip surgery, introduced by William H. Harris in 1969.

Harris–Benedict equation

Harris–Benedict equation: regression formula by Harris and Benedict (1919, revised by Roza and Shizgal 1984) estimating adult basal metabolic rate from weight, height, age, and sex; distinct from Mifflin-St Jeor and WHO equations.

Harrison C. Spencer

Harrison C. Spencer, born Harrison Clark Spencer Jr., was an American malaria epidemiologist who led the London School of Hygiene & Tropical Medicine and ASPPH.

Harry P. Cain II

Harry P. Cain II (1937–2023) was an American health policy scholar and executive, a National Academy of Medicine member who led Blue Cross and Blue Shield operations.

Hartmann's procedure

Hartmann's procedure is an emergency colorectal operation that removes the diseased sigmoid colon and upper rectum, closes the rectal stump, and brings the proximal colon out as an end colostomy.

Hartnup disease

Hartnup disease (Hartnup disorder), an autosomal recessive SLC6A19/B0AT1 transport defect causing neutral aminoaciduria, pellagra-like photosensitive rash, ataxia, and psychiatric symptoms, treated with nicotinamide and a high-protein diet.

Hartsfield syndrome

Hartsfield syndrome (holoprosencephaly-ectrodactyly-cleft lip/palate syndrome, OMIM 615465) is a rare FGFR1-related disorder combining holoprosencephaly, split-hand/foot malformation, cleft lip/palate, and endocrine abnormalities, inherited dominantly or recessively.

Harvard step test

The Harvard step test is a submaximal field test of cardiovascular fitness in which heart rate recovery after stepping on and off a bench yields a fitness index.

HAS-BLED

The HAS-BLED score estimates the 1-year risk of major bleeding in patients with atrial fibrillation on oral anticoagulation, with a score of 3 or higher flagging high risk.

Hash oil

Hash oil, also called butane hash oil or cannabis extract, is a solvent-made cannabis concentrate with up to 90% THC versus about 12% in flower, consumed by dabbing or vaping, with fire, contamination, and dependence risks.

Hashimoto's thyroiditis

Hashimoto's thyroiditis (chronic lymphocytic thyroiditis, autoimmune thyroiditis) is an autoimmune destruction of the thyroid and the most common cause of hypothyroidism, first described by Hakaru Hashimoto in 1912, affecting about 7.5% of adults worldwide and four times more women than men, treated with levothyroxine.

Hashish

Hashish (حشيش) is compressed cannabis resin from female flowering tops, controlled as cannabis resin under the 1961 Single Convention; THC content rose 66% in Europe 2014–2024, distinct from marijuana and hash oil.

Hasnat Khan

Hasnat Ahmad Khan (born 1959, Jhelum, Pakistan) is a British-Pakistani cardiothoracic surgeon at Basildon University Hospital, Essex, known for his secret 1995-1997 relationship with Princess Diana, later covered in the book Diana: Her Last Love, the 2013 film Diana, and The Crown.

Havana syndrome

Havana syndrome, or anomalous health incidents (AHI): symptoms first reported by US Embassy Havana staff in 2016, later hundreds of cases worldwide; cause contested, with US intelligence judging foreign adversary involvement very unlikely and NIH finding no MRI-detectable brain injury.