Human health and medicine

Cordotomy

Cordotomy is a neurosurgical procedure cutting pain fibers in the spinal cord, used to relieve severe, medication-refractory cancer pain on one side of the body.

Core decompression is an orthopedic operation that drills channels into the femoral head to relieve pressure and preserve the joint in early-stage avascular necrosis, with a pooled success rate of 65%.

Core needle biopsy

Core needle biopsy is a percutaneous procedure in which a hollow cutting needle, typically 9 to 20 gauge, removes a small cylinder of tissue for histologic examination, preserving tissue architecture.

Corewell Health

Corewell Health is Michigan's not-for-profit health system formed February 1, 2022 from the Beaumont Health and Spectrum Health merger, renamed from BHSH in October 2022, with 21 hospitals, 60,000+ team members, and the Priority Health plan.

Corifollitropin alfa

Corifollitropin alfa (Elonva) is a long-acting recombinant FSH analogue with an hCG C-terminal peptide fusion, half-life about 70 hours; one injection replaces seven daily FSH injections in IVF ovarian stimulation; EU-approved 2010, not FDA-approved.

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.

Corneal abscess

Corneal abscess, a suppurative form of infectious keratitis appearing as a white corneal opacity, caused by bacteria, fungi, or parasites; diagnosed by corneal scraping or suture sampling, treated with fortified topical antibiotics and sometimes keratoplasty.

Corneal collagen cross-linking

Corneal collagen cross-linking (CXL) is an ophthalmic procedure that stiffens the cornea using riboflavin and UVA light, halting progression of keratoconus and post-LASIK ectasia; the original Dresden protocol remains the reference standard.

Corneal deformities

Corneal deformities (ICD-11 9A78.5) are abnormal corneal shapes, chiefly keratoconus (9A78.50) and corneal staphyloma (9A78.51), causing blurred vision and irregular astigmatism, treated with lenses or keratoplasty.

Corneal degeneration

Corneal degeneration (ICD-10 H18.4, ICD-11 9A78.4) covers acquired corneal changes from aging, metabolism, or inflammation, unlike hereditary dystrophies; examples include arcus senilis, band keratopathy, and Salzmann nodular degeneration.

Corneal densitometry

Corneal densitometry is an ophthalmic imaging measurement that quantifies backscattered light from the cornea using a rotating Scheimpflug camera, used to follow corneal opacity in keratoconus and after cross-linking.

Corneal dystrophy-perceptive deafness syndrome

Corneal dystrophy-perceptive deafness syndrome, or Harboyan syndrome (CDPD), is a rare autosomal recessive SLC4A11 disorder combining congenital corneal endothelial dystrophy with progressive postlingual sensorineural hearing loss, OMIM 217400.

Oct 20, 2026

Corneal endotheliitis

Corneal endotheliitis is inflammation centered on the corneal endothelium, the cell layer keeping the cornea clear, causing corneal edema; most cases are viral, chiefly herpesviruses like cytomegalovirus, and delayed treatment risks irreversible endothelial cell loss.

Corneal neovascularization

Corneal neovascularization: abnormal ingrowth of new blood vessels from the limbus into the normally avascular cornea, caused by hypoxia, inflammation, infection, or graft rejection; treated with steroids, anti-VEGF agents, and laser therapy.

Corneal oedema

Corneal oedema (corneal edema) is excess water in the cornea causing swelling and loss of transparency, mainly from endothelial dysfunction (Fuchs dystrophy, bullous keratopathy, cataract surgery). Treated with hypertonic saline or endothelial keratoplasty.

Corneal pachymetry

Corneal pachymetry is the measurement of corneal thickness, most often central thickness of about 540 µm, using ultrasound or optical instruments to assess glaucoma risk and screen for refractive surgery.

Corneal reflex

The corneal reflex, also called the blink reflex, closes both eyelids when the cornea is touched, protecting the eye and testing cranial nerves V and VII.

Corneal scars or opacities

Corneal scars or opacities (leukoma; ICD-10 H17, ICD-11 9A77) are loss of corneal transparency from scarring by infectious, inflammatory, congenital, dystrophic, or traumatic causes, treated mainly by keratoplasty.

Corneal staphyloma

Corneal staphyloma (anterior staphyloma) is a rare ectatic, uveal-lined bulging of an opaque cornea, congenital or acquired after corneal perforation, treated by sclerokeratoplasty or penetrating keratoplasty rather than evisceration.

Corneal tattooing

Corneal tattooing, or keratopigmentation, deposits pigment into the corneal stroma to disguise corneal scars, mask iris-defect symptoms, or change eye color; practiced since Galen, modernized by Von Wecker in 1869, with no FDA-approved pigments.

Corneal tomography

Corneal tomography is an ophthalmic imaging method that reconstructs a 3D model of the cornea and anterior segment, and the current standard for detecting keratoconus and screening refractive surgery candidates.

Corneal topography

Corneal topography is a non-invasive, computer-aided imaging method that maps the front surface of the cornea, used to diagnose keratoconus and screen candidates for laser refractive surgery.

Corneal transplantation

Corneal transplantation (keratoplasty) replaces diseased corneal tissue with donor cornea. First done by Eduard Zirm in 1905; types include PK, DALK, DSAEK, and DMEK; global supply is 1 cornea per 70 needed.

Corneal ulcer

Corneal ulcer (ulcerative keratitis): an open sore on the cornea, usually infectious (bacterial, viral, fungal, Acanthamoeba), an ocular emergency. Contact lens wear is the leading risk factor; treated with intensive topical antibiotics.

Oct 22, 2026

Cornell dots

Cornell dots, also called C dots or C' dots, are ultrasmall fluorescent silica nanoparticles developed at Cornell University in 2005 to light up cancerous tumors for surgeons.

Cornell Medical Index

The Cornell Medical Index (CMI) is a 195-question yes/no self-administered health questionnaire created in 1949 at Cornell University Medical College, widely used for medical history, screening, and epidemiology until its 1991 phase-out.

Corneometry

Corneometry is a dermatological technique that measures hydration of the stratum corneum, the skin's outermost layer, using a capacitive sensor pressed against the skin surface.

Corns or callosities

Corns or callosities (calluses, clavi, helomas) are focal thickenings of the skin's horny layer caused by repeated friction or pressure, usually over bony prominences; corns are painful, sharply demarcated, and treated by removing the causative force.