2,701 articles
Cybathlon
Cybathlon is an international competition organized by ETH Zurich where pilots with disabilities complete everyday tasks using prostheses, exoskeletons, and brain-computer interfaces; it was first held in 2016.
Cyborg
Cyborg: a cybernetic organism, a human integrally combined with technology. Coined by Clynes and Kline in 1960 for space-flight self-regulation; today covers brain-computer implants, prosthetics, and human augmentation.
Cyclopia
Cyclopia (synophthalmia) is the most severe facial form of holoprosencephaly: a single central eye with absent nose or proboscis, caused by failed forebrain division; prevalence 1 in 100,000 births, lethal within days, linked to SHH mutations, trisomy 13, and cyclopamine.
Cystic hygroma
Cystic hygroma, also called cystic lymphangioma or macrocystic lymphatic malformation, is a benign congenital lymphatic malformation forming large fluid-filled cysts, usually in the neck, treated by surgery or sclerotherapy.
Cystoid macular dystrophy
Cystoid macular dystrophy, also called dominant cystoid macular dystrophy (DCMD), is a rare autosomal dominant retinal disorder in which cystoid macular edema appears in childhood and progresses to macular atrophy with poor vision.
D1/D2-hybrid medium spiny neuron
D1/D2-hybrid medium spiny neuron, also called D1/D2-SPN or D1/D2-coexpressing MSN, a striatal projection neuron coexpressing dopamine D1 and D2 receptors with dynorphin and enkephalin; proposed third basal ganglia pathway bearing the D1–D2 receptor heteromer, rare but motor-functionally significant.
D341 Med
D341 Med (D-341 Med, CVCL_0018, ATCC HTB-187) is a human group 3 medulloblastoma cell line established in 1988 from a 3.5-year-old boy's cerebellar tumor, grown in suspension spheroids with 20-fold c-myc amplification.
Da Costa's syndrome
Da Costa's syndrome, or irritable heart, soldier's heart, effort syndrome, or neurocirculatory asthenia, is a functional cardiac disorder with effort intolerance, palpitations, and breathlessness described by Jacob Mendes Da Costa in 1871.
Danger triangle of the face
The danger triangle of the face, also called the nasolabial triangle, spans from the nose bridge to the mouth corners, where infections can spread to the brain.
Daniel Hale Williams
Daniel Hale Williams (1856–1931), American surgeon, founded Chicago's interracial Provident Hospital in 1891, sutured James Cornish's pericardium after a heart stab wound in 1893, co-founded the National Medical Association, and was the first Black Fellow of the American College of Surgeons.
DAPA-HF trial
DAPA-HF (Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure), NCT03036124: phase 3 trial of 4,744 patients showing dapagliflozin 10 mg daily reduced worsening heart failure or cardiovascular death (HR 0.74) in HFrEF with or without diabetes.
Dark Adaptation
Dark adaptation is the slow recovery of visual sensitivity in darkness after light bleaches rhodopsin, taking 30–40 minutes, driven by the retinoid cycle, and delayed in AMD, where rod intercept time is a clinical biomarker.
Dead on arrival
Dead on arrival (DOA), also cardiopulmonary arrest on arrival (CPAOA), is a person found dead or with ceased heart or lung function at EMS or hospital arrival; diagnosis, prehospital death determination, and classification effects on survival statistics.
Dead space (physiology)
Dead space (physiology): wasted ventilation, the lung volume not participating in CO2 exchange; anatomic plus alveolar dead space, measured by Bohr or Enghoff equations, elevated in ARDS and pulmonary embolism.
Death
Death: permanent cessation of organism function, determined medically by circulatory-respiratory or neurologic (brain death) criteria under the 1981 UDDA; covers Harvard criteria, 2023 BD/DNC guidelines, DCD donation, and global mortality statistics.
Death during consensual sex
Death during consensual sex, usually sudden cardiac death from myocardial infarction or arrhythmia triggered by the modest 3-5 MET exertion of intercourse; rare, about 0.2% of sudden cardiac deaths, mostly older men with coronary disease.
Deep brain stimulation
Deep brain stimulation (DBS) is neurosurgical implantation of electrodes and a pacemaker-like neurostimulator to treat Parkinson's disease, essential tremor, dystonia, OCD, and epilepsy; FDA-approved since 1997, with the first adaptive closed-loop system approved in February 2025.
Deep hypothermic circulatory arrest
Deep hypothermic circulatory arrest (DHCA) is a cardiac and aortic surgery technique cooling the body to 15–25 °C to stop circulation safely; pioneered by Bigelow, Drew, and Griepp, now often replaced by moderate hypothermia with antegrade cerebral perfusion.
Deep vein thrombosis
Deep vein thrombosis (DVT) is a blood clot in a deep vein of the leg, pelvis, or arm, part of venous thromboembolism; diagnosed by duplex ultrasound, treated with anticoagulants, and complicated by pulmonary embolism and post-thrombotic syndrome.
Deepak Pandya
Deepak N. Pandya (1932-2020), Indian-American neuroanatomist and physician at Bedford VA and Boston University, mapped primate cortical connections, defined core-belt auditory cortex, and was father of astronaut Sunita Williams.
Default mode network
Default mode network (DMN), also called default network, a brain network of medial prefrontal, posterior cingulate, precuneus, angular gyrus, and temporal regions active at rest and during internal thought, suppressed during attention-demanding tasks; named by Raichle et al. 2001.
Defecation
Defecation is the expulsion of feces through the anus, coordinated by the enteric, spinal, and central nervous systems, the pelvic floor, and the anal sphincters; most people defecate 1 to 3 times daily.
Degenerative disease
A degenerative disease, also called a degenerative disorder, is one marked by progressive deterioration in how affected tissues or organs work; examples include osteoarthritis, osteoporosis, and Alzheimer disease.
Delayed encephalopathy due to carbon monoxide poisoning
Delayed encephalopathy due to carbon monoxide poisoning, also called delayed neuropsychiatric sequelae, is a rare neurological disorder that emerges weeks after apparent recovery from carbon monoxide poisoning, causing cognitive impairment, personality changes, and parkinsonism.
Delta wave
Delta wave: high-amplitude 1–4 Hz (band 0.1–<4 Hz) EEG rhythm dominating N3 slow-wave sleep; also seen in anesthesia and coma, generated by thalamic h-current/T-current interactions and cortical layer 5 circuits; named by Walter in 1936.
Deltoid muscle
Deltoid muscle (musculus deltoideus), the triangular shoulder-cap muscle with clavicular, acromial, and spinal parts; axillary nerve (C5, C6); abducts, flexes, extends the arm; preferred adult vaccination site.
Demecarium
Demecarium (demecarium bromide, Humorsol, Tosmilen, BC-48) is a long-acting cholinesterase inhibitor miotic for glaucoma, FDA approved 1959 and now discontinued; it survives in veterinary use via compounding pharmacies.
Dementia due to Down syndrome
Dementia due to Down syndrome (ICD-11 6D85.9) is an Alzheimer-like neurodegenerative disorder caused by chromosome 21 triplication and APP overexpression; dementia prevalence rises from about 3.4% at ages 30-39 to roughly 70% after age 50.
Dendritic spine
Dendritic spines (espinas) are small actin-rich protrusions on neuronal dendrites forming the postsynaptic side of most excitatory synapses; discovered by Cajal in 1888, they number 1-10 per micrometer and remodel during learning, aging, and disease.
Dentate gyrus
Dentate gyrus, hippocampal subregion and input channel of the hippocampal formation; three-layered cortex with granule cells, mossy fibers to CA3, adult neurogenesis in the subgranular zone, and a debated role in pattern separation.