2,701 articles
Cine Magnetic Resonance Imaging
Cine MRI (cine CMR, Magnetic Resonance Imaging, Cine) is a cardiac MRI technique using ECG-gated bSSFP sequences to display heart motion as a movie loop and quantify ventricular volumes and ejection fraction, the reference standard for LV systolic function.
Cingulate cortex
Cingulate cortex: paired medial-wall brain region of the limbic system, divided into ACC, midcingulate, posterior cingulate, and retrosplenial cortex; roles in emotion, decision-making, pain, memory, and cingulotomy surgery.
Circle of Willis
Circle of Willis (circulus arteriosus cerebri): anastomotic arterial ring at the brain base linking internal carotid and vertebrobasilar systems; primary cerebral collateral supply, complete in only about 12–36% of adults, linked to aneurysms and stroke outcomes.
Circulatory system
Circulatory system, also called cardiovascular system: the heart, blood vessels, and blood that move blood through the body. Covers open vs closed systems, pulmonary and systemic circuits, Harvey's 1628 discovery, and cardiovascular disease burden.
Circulatory transition at birth
Circulatory transition at birth is the switch from fetal to adult circulation: lung aeration and cord clamping reverse pressure gradients, closing the foramen ovale, ductus arteriosus, and ductus venosus.
Claudication
Claudication (intermittent claudication) is exertional leg pain relieved by rest, caused by atherosclerotic PAD, affecting about 4.5% of people over 40; treated with supervised exercise, cilostazol, and revascularization when needed.
Clavicle
Clavicle (collarbone): the doubly curved bone linking sternum and scapula, the only bony connection of arm to trunk. Ossifies first among long bones; fractures are ~5% of adult fractures.
Climatic droplet keratopathy
Climatic droplet keratopathy (CDK), also called Labrador keratopathy or spheroidal degeneration, is a rare acquired corneal degeneration from chronic UV and environmental exposure, causing golden subepithelial droplets, graded 1 to 3, treatable only by corneal transplantation.
Clinical cardiology
Clinical cardiology is the non-surgical medical specialty concerned with the diagnosis, assessment, management, and prevention of heart and circulation disorders, including coronary disease and heart failure.
Clinical course and progression of ALS
The clinical course and progression of ALS covers how the disease begins, spreads, and is staged, with median survival of 2 to 4 years after symptom onset.
Clinical death
Clinical death is the reversible stage of dying after heartbeat and breathing stop, before brain cells irreversibly die; distinct from brain death. CPR and defibrillation can reverse it, rarely beyond 30 minutes except in hypothermia.
Clinical presentation of brain tumors
The clinical presentation of brain tumors is the symptoms and signs an intracranial mass produces, including headache, seizures, raised intracranial pressure, and focal deficits that reflect the tumor's location.
Clitoral erection
Clitoral erection: engorgement of the clitoris during arousal via NO/cGMP/PKG activation of BK(Ca) channels in erectile tissue homologous to the penis, innervated by S2–S4 parasympathetic cavernous nerves.
Clitoral hood
Clitoral hood (prepuce of the clitoris): skin fold formed by the labia minora covering the glans clitoris; coverage varies widely; associated conditions include clitoral adhesions and phimosis.
CLN10 disease
CLN10 disease (neuronal ceroid lipofuscinosis type 10, cathepsin D deficiency) is a rare autosomal recessive lysosomal storage disorder caused by CTSD mutations; the congenital form is the most severe NCL, with microcephaly, seizures, and death within hours to weeks of birth.
CLN11 disease
CLN11 disease (neuronal ceroid lipofuscinosis 11, NCL11) is a rare autosomal recessive Batten disease spectrum disorder caused by biallelic GRN mutations, causing seizures, retinitis pigmentosa, ataxia, and cognitive decline from about age 13 to 25; single-copy GRN carriers risk frontotemporal dementia instead.
CLN13 disease
CLN13 disease (Kufs disease type B, NCL13) is a rare autosomal recessive adult-onset neuronal ceroid lipofuscinosis caused by CTSF mutations, producing cathepsin F deficiency, dementia, and movement disturbances without vision loss.
CLN3 disease
CLN3 disease (juvenile neuronal ceroid lipofuscinosis, juvenile Batten disease) is an autosomal recessive lysosomal storage disorder from CLN3 gene mutations, causing childhood vision loss, seizures, cognitive decline, and death typically at 20–30 years.
CLN5 disease
CLN5 disease is a rare inherited neurodegenerative disorder of the Batten disease group, caused by CLN5 gene mutations and marked by seizures, ataxia, and vision loss.
CLN8 disease
CLN8 disease (Northern epilepsy, EPMR; OMIM 600143) is an autosomal recessive neuronal ceroid lipofuscinosis caused by CLN8 gene mutations, with a milder Finnish epilepsy form and a severe late-infantile form with vision loss.
Clonus
Clonus: involuntary rhythmic muscle contractions from sudden passive tendon stretching, an upper motor neuron sign elicited by rapid ankle dorsiflexion; 5-8 Hz beats, sustained if over 10, treated with baclofen, cold, botulinum toxin, or phenol.
Closing Volume
Closing volume is the expired lung volume between the onset of small-airway closure in dependent lung zones and residual volume; closing capacity equals closing volume plus residual volume. It rises linearly with age, measured by single-breath nitrogen washout, and exceeds FRC in the elderly.
Clot Retraction
Clot retraction (clot contraction): platelet-driven shrinkage of a fibrin blood clot via integrin αIIbβ3 outside-in signaling and the actin-myosin cytoskeleton, expelling serum, stabilizing the clot, and retarding fibrinolysis.
CNTRACS trial
CNTRACS (Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia Consortium) is a five-site NIMH program, not a drug trial, validating cognitive neuroscience tasks (DPX, RISE, CCE, JOVI) as clinical trial measures in schizophrenia, now extended computationally (NCT07853807).
Coagulation
Coagulation: blood clotting via platelet-fibrin plug formation. Modeled historically by the 1960s cascade and currently by the Hoffman-Monroe cell-based model (initiation, amplification, propagation), with anticoagulant regulation and fibrinolysis.
COASY protein-associated neurodegeneration
COASY protein-associated neurodegeneration (CoPAN, NBIA6, OMIM 615643) is an ultra-rare autosomal recessive childhood-onset neurodegeneration with brain iron accumulation caused by COASY mutations impairing the final steps of coenzyme A biosynthesis.
Cocaine-associated acute coronary syndrome
Cocaine-associated acute coronary syndrome is unstable angina or heart attack triggered by cocaine use, typically affecting younger patients and managed differently, with beta-blockers generally avoided early.
Coccyx
Coccyx (tailbone): terminal segment of the human vertebral column, three to five fused rudimentary vertebrae (usually four) articulating with the sacrum; anchors pelvic floor muscles and ligaments, bears seated weight, and is the site of coccydynia.
Cochlea
Cochlea: fluid-filled, spiral-shaped inner-ear cavity (2.5 turns) housing the organ of Corti; transduces sound via hair cells along a tonotopic basilar membrane; site of sensorineural hearing loss, cochlear implants, and new gene therapies.
Cochlear amplifier
Cochlear amplifier: active process in the mammalian cochlea, also called cochlear amplification, where outer hair cells and prestin enhance basilar membrane vibration, giving hearing sensitivity, sharp tuning, and otoacoustic emissions.