2,701 articles
Congenital cornea plana
Congenital cornea plana (cornea plana congenita, CNA1/CNA2) is a rare bilateral flattening of the cornea causing high hyperopia; recessive CNA2 stems from KERA (keratocan) mutations, dominant CNA1 is milder and genetically unexplained.
Congenital Gerbode defect
The congenital Gerbode defect is a rare abnormal communication shunting blood from the left ventricle directly into the right atrium, accounting for less than 1% of congenital cardiac defects.
Congenital hearing loss
Congenital hearing loss is deafness present at birth, about half genetic and half environmental; congenital CMV is the leading nongenetic cause, detected through universal newborn hearing screening.
Congenital heart block
Congenital heart block: fetal/neonatal AV conduction disorder, usually autoimmune from maternal anti-SSA/Ro and anti-SSB/La antibodies (neonatal lupus), detected 16-24 weeks, ~20% mortality, most survivors need pacemakers.
Congenital heart defect
A congenital heart defect is a structural abnormality of the heart or great vessels present at birth, affecting nearly 1% of live births and leading causes of infant mortality.
Congenital primary aphakia
Congenital primary aphakia (CPAK, OMIM 610256) is a rare birth defect in which the eye's lens never forms, caused mainly by autosomal recessive FOXE3 variants, with anterior segment aplasia, microphthalmia, and glaucoma.
Congenital pulmonary vein atresia
Congenital pulmonary vein atresia: rare congenital obstruction of pulmonary veins at the left atrial junction, from failed common pulmonary vein incorporation; forms include common, unilateral, and individual atresia, presenting with tachypnea, pneumonia, or hemoptysis.
Conjunctiva
Conjunctiva (tunica conjunctiva): transparent mucous membrane lining the eyelids and covering the sclera except the cornea; secretes tear mucus, guards against infection; affected by conjunctivitis and subconjunctival hemorrhage.
Conjunctival scars
Conjunctival scars are permanent fibrous changes in the conjunctiva, the membrane covering the eye; with chronic inflammation the condition is cicatrizing conjunctivitis, with incidence about 1.3-1.5 per million.
Conjunctival vascular disorders
Conjunctival vascular disorders (ICD-11 9A61.4; conjunctival vascular disease) are disorders of conjunctival blood vessels, covering hyperemia, subconjunctival hemorrhage, and vascular tumors and malformations such as lymphangioma and hemangioma.
Conjunctivitis
Conjunctivitis (pink eye) is inflammation of the conjunctiva causing red, discharging eyes; mainly viral (~80% of infectious cases), bacterial, or allergic; contagious viral and bacterial forms usually self-resolve.
Conjunctivochalasis
Conjunctivochalasis (CCH), also called conjunctival chalasis, is a loose, redundant folding of the bulbar conjunctiva, typically bilateral and inferior, mainly from aging, causing tear film instability, irritation, and epiphora; treated with lubricants, anti-inflammatories, or conjunctival excision or cauterization.
Connectome
Connectome: the complete map of neural connections in a nervous system, coined by Sporns and Hagmann in 2005. Studied at micro, meso, and macroscales via tractography and fMRI; central to the Human Connectome Project.
Connectomics
Connectomics: neuroscience field mapping complete neural wiring diagrams (connectomes), coined 2005 by Sporns and Hagmann; spans dMRI tractography in humans, EM datasets like FlyWire (139,255 fly neurons) and MICrONS, and the Human Connectome Project.
Consciousness
Consciousness, also called subjective or phenomenal experience, is the presence of first-person experience; studied via global workspace, IIT, and higher-order theories, with neural correlates and clinical disorders of consciousness.
Constitutional tall stature
Constitutional tall stature (familial tall stature, 体質性高身長, ICD-11 5B12, ICD-10-CM E34.4): a benign normal-variant height more than 2 SD above age and sex mean, the most common cause of tall stature, diagnosed by excluding gigantism, Marfan, and endocrine causes.
Constrained spherical deconvolution
Constrained spherical deconvolution (CSD) is a diffusion MRI method introduced in 2007 that estimates fiber orientation distributions in the brain, using a non-negativity constraint and implemented in MRtrix3.
Consumer neurotechnology industry
The consumer neurotechnology industry sells non-implanted, non-clinical devices, mostly wireless EEG headsets and headphones, for sleep tracking, meditation, focus monitoring, and gaming, sold as consumer electronics rather than medical devices.
Contact lens
Contact lens: thin corrective, cosmetic, or smart lens worn on the eye; soft and RGP types; first corrective lenses 1888 (Fick, Kalt), hydrogel 1959, disposables 1982, silicone hydrogel 1999; over 140 million wearers.
Contact lens-associated corneal infiltrates
Contact lens-associated corneal infiltrates, also called corneal infiltrative events, are white inflammatory cell aggregates in the cornea of lens wearers; distinguishing sterile infiltrates from microbial keratitis drives urgent management.
Contracted socket
Contracted socket (eye), also called socket contracture after enucleation or evisceration: shrinkage of anophthalmic orbital tissue with shallow fornices that prevents retention of an ocular prosthesis; graded by severity and treated with grafts, implants, and flaps.
Contrast (vision)
Contrast in vision is the difference in lightness or darkness between an object and its background; contrast sensitivity testing can detect eye diseases that standard acuity measurement misses.
Conus medullaris
Conus medullaris: the cone-shaped tapered end of the spinal cord, terminating around L1 (range T12-L3) in adults. Key facts: embryonic ascent, tethered cord thresholds, lumbar puncture safety, conus medullaris syndrome.
Cooper's ligaments
Cooper's ligaments, the suspensory ligaments of the breast (ligamenta suspensoria), are collagenous strands described by Astley Cooper in 1840 that tether the breast skin to the pectoral fascia, providing support, shape, and skin tethering in cancer.
Cor triatriatum
Cor triatriatum: rare congenital heart defect, also called cor triatriatum sinister or dexter, in which a fibromuscular membrane divides an atrium into three chambers; about 0.1% of congenital heart disease, treated by surgical membrane resection.
Cor triatriatum dexter
Cor triatriatum dexter (cor triatriatum dextrum, CTD): rare congenital heart defect in which a persistent right sinus venosus valve membrane divides the right atrium into two chambers, causing cyanosis, dyspnoea, or right heart failure, often with atrial septal defect.
Coracoid process
Coracoid process: hook-shaped projection of the scapula, the shoulder's "lighthouse" landmark; anchors pectoralis minor, biceps short head, coracobrachialis and four ligaments; graft source in Latarjet instability surgery.
CORDIOPREV trial
CORDIOPREV (NCT00924937): Spanish single-centre randomized trial in 1,002 coronary heart disease patients comparing a Mediterranean diet with a low-fat diet over 7 years; Mediterranean diet reduced major cardiovascular events by 26% (33% in men).
Cornea
Cornea: transparent front tissue of the eye, major refractive element; five layers including non-regenerating endothelium; site of keratoplasty, first performed by Zirm in 1905, now supplemented by endothelial cell therapy.
Corneal abrasion
Corneal abrasion, a scratch of the corneal epithelium, is a common eye injury from trauma, foreign bodies, or contact lenses. Diagnosed with fluorescein and slit lamp; heals in 1-3 days; patching not recommended and antibiotic benefit unproven.