2,701 articles
Ductus venosus
Ductus venosus: fetal vessel connecting the umbilical vein to the inferior vena cava, shunting oxygenated placental blood past the liver; closes after birth to form the ligamentum venosum; key Doppler marker in fetal growth restriction.
Duodenum
Duodenum: first, C-shaped segment of the small intestine, 25–30 cm, from pylorus to ligament of Treitz; receives bile and pancreatic secretions via ampulla of Vater; secretes secretin, CCK, GIP; site of celiac biopsy and peptic ulcers.
Dura mater
Dura mater (hard mother, pachymeninx): tough outermost meninx of brain and spinal cord, with cranial periosteal and meningeal layers forming venous sinuses and folds like the falx cerebri and tentorium.
Dural sinus malformation with arteriovenous shunt
Dural sinus malformation with arteriovenous shunt (DSM, ORPHA:97339), a rare congenital neurovascular malformation with massively dilated dural sinuses and AV shunts, presenting in neonates and infants with macrocrania, heart failure, or hemorrhage.
Dysautonomia
Dysautonomia, also called autonomic dysfunction or autonomic neuropathy, is an umbrella term for disorders of the autonomic nervous system, covering POTS, pure autonomic failure, familial dysautonomia, and secondary forms from diabetes or Parkinson disease.
Dysphagia lusoria
Dysphagia lusoria (Bayford syndrome) is difficulty swallowing from esophageal compression by an aberrant right subclavian artery, a congenital aortic arch anomaly in 0.5-2.5% of people, mostly asymptomatic.
Eales disease
Eales disease, first described by Henry Eales in 1880, is an idiopathic occlusive retinal perivasculitis of young men causing neovascularization and recurrent vitreous hemorrhage, linked to tuberculosis, treated with steroids, laser, and vitrectomy.
Ear canal
Ear canal (external auditory canal, external acoustic meatus): the tube from the outer ear opening to the eardrum. Resonates at 2–4 kHz, forms from a meatal plug canalizing at 28–32 weeks, prone to exostoses in cold-water surfers.
Eardrum
Eardrum (tympanic membrane): thin circular tissue about 1 cm wide separating outer and middle ear, vibrating to transmit sound to the ossicles. Three-layered, derived from all germ layers; about 80% of perforations heal spontaneously.
Earlobe
Earlobe (lobule): the soft, cartilage-free lower part of the external ear made of fibrofatty tissue; pierced commonly, elongates with age, polygenic attached-versus-free attachment, site of Frank's sign.
Early age-related macular degeneration
Early age-related macular degeneration (early AMD, ICD-11 9B75.00, AREDS category 2) is the AMD stage defined by medium drusen 63–125 µm without pigmentary abnormalities, asymptomatic, low progression risk, no treatment.
Early human development
Early human development: the field covering fetal, perinatal, and infant neurodevelopment, and the Elsevier journal Early Human Development (ISSN 0378-3782, founded 1977) publishing that research.
Early-onset Alzheimer's disease
Early-onset (younger-onset) Alzheimer's disease is Alzheimer's beginning before age 65, about 5% of US cases. Familial forms come from APP, PSEN1, and PSEN2 mutations; lecanemab and donanemab modestly slow early symptomatic disease.
Early-onset cerebellar ataxia with retained tendon reflexes
Early-onset cerebellar ataxia with retained tendon reflexes, also called EOCARR or Harding ataxia, is a rare inherited ataxia starting in childhood that resembles Friedreich ataxia but keeps brisk tendon reflexes.
Earwax
Earwax, or cerumen, is the waxy secretion of ear canal glands that protects and cleans the ear. Wet and dry types follow the ABCC11 gene; impaction affects up to 30% of people and is treated with softeners, irrigation, or manual removal.
Eating
Eating is the ingestion of food through the mouth for nourishment, covering mastication, swallowing, brain-regulated satiety, the evolution of human diets, and modern guidance on ultraprocessed foods and healthy eating patterns.
Ebstein's anomaly
Ebstein malformation of the tricuspid valve (Ebstein anomaly), a rare congenital heart defect with apically displaced tricuspid leaflets and atrialized right ventricle; described by Wilhelm Ebstein in 1866, treated by cone repair.
Echocardiography
Echocardiography, also known as cardiac ultrasound, is a non-invasive test using ultrasound waves to image the heart, developed by Inge Edler and Carl Hertz in Sweden in 1953.
Ectopia cordis
Ectopia cordis, or ectopic heart, is a rare congenital defect in which the heart lies partly or wholly outside the thorax through an anterior chest wall defect; prevalence 5.5–7.9 per million births, often with pentalogy of Cantrell, survival about 10%.
Ectopic thymus
Ectopic thymus, also called ectopic cervical or intrathyroidal thymus, is thymic tissue stranded along the embryological descent path from the third pharyngeal pouch; a benign pediatric neck or thyroid finding that can mimic cancer.
Ectropion of eyelid
Ectropion of the eyelid: outward turning of the eyelid margin, usually the lower lid, exposing the inner surface. Main types involutional, cicatricial, mechanical, paralytic; treated with lubricants and lateral tarsal strip surgery.
Edaravone (エダラボン)
Edaravone (エダラボン; Radicut/Radicava) is a free-radical scavenging drug approved in Japan (2001) for acute ischemic stroke and in the US (2017 IV, 2022 oral) to slow decline in ALS, one of three FDA-approved ALS drugs.
Edinger–Westphal nucleus
The Edinger–Westphal nucleus (E-W nucleus), described by Edinger in 1885 and Westphal in 1887, is a midbrain cell group whose preganglionic neurons control pupil constriction and lens accommodation.
Edward H. Frank
Edward H. Frank is an American electrical engineer and technology executive who co-founded Epigram, led Broadcom's early Wi-Fi business, and served as Apple's Vice President of Macintosh Hardware Systems Engineering.
EEGLAB
EEGLAB is an open-source MATLAB toolbox for single-trial EEG analysis with ICA, first released April 23, 2001 by Delorme and Makeig at UCSD's Swartz Center; about 120 plugins, Octave support, and Python bridges via EEGPrep.
Eigengrau
Eigengrau (Eigenlicht, dark light, brain gray) is the intrinsic dark gray seen in total darkness, a term credited to Gustav Fechner, caused by spontaneous retinal dark noise from visual pigment and phototransduction fluctuations.
Ejaculatory duct
Ejaculatory duct: paired ~2 cm tubes formed by union of the seminal vesicle duct and vas deferens ampulla, passing through the prostate to the verumontanum; obstruction causes 1–5% of male infertility.
Ejection fraction
Ejection fraction (EF), or LVEF, is the percentage of left ventricular blood volume ejected per heartbeat; normal 55–70%. It classifies heart failure as reduced, preserved, or improved EF, with 2026 guidelines simplifying categories.
Elaine Esposito
Elaine Esposito (1934-1978), the "sleeping beauty," fell into a coma aged six during a 1941 Chicago appendectomy and never woke, holding the Guinness longest-coma record at 37 years 111 days until her death in Florida.
Elbow
The elbow (articulatio cubiti) is the compound synovial hinge joint of humerus, radius, and ulna, with three articulations, collateral ligament stabilizers, 0–140° motion, and common injuries including dislocation and epicondylitis.