Online Medical Dictionary

Letter O

OB: Abbreviation for obstetrician.
OB/GYN: Abbreviation an obstetrician gynecologist.
Obesity-related Disease: Any disease to which obesity increases the risk of developing. Obesity-related diseases may include type-2 diabetes, high blood pressure, stroke, heart attack, congestive heart failure, prostate cancer, colon cancer, gallstones, gout, osteoarthritis and sleep apnea.
Obstetrician: A physician specialized in obstetrics,or the care of woman and child throughout pregnancy, childbirth, and during the post-natal period.
Obstetrics: The medical specialty focused on the care of a woman and child during the prenatal period, the delivery period and the post-natal (after childbirth) period. Obstetrics includes imaging, monitoring, induction procedures, supervising labor and monitoring for complications after the child is delivered.
Obstruction: Blockage of a passage, impeding natural flow from occurring.
Occlusion: A closure or obstruction in a vessel or passageway, impeding natural flow.
Occupational Disease: An illness or condition that occurs as a result of factors present in an individual's occupational environment.
OCD: Abbreviation for obsessive-compulsive disorder.
Ocular: Regarding the eye(s).
Ocular Prosthesis: An artificial replacement for the natural eye, normally following an evisceration or enucleation, wherein the eye is removed but eye muscles are left intact, usually conducted due to extricate ocular tumour.
Oculoplastics: A term used to describe the many oculoplastic surgeries or reconstructive eye surgeries that may be conducted to correct structures of the eye, including the tear ducts, the eyelids and the eye socket (the orbit).
Olfactory: Pertaining to the sense of smell.
Olfactory Disorder: The impeded inability to perceive scent (hyposmia); or, the ability to perceive an overabundance of scent (hyperosmia). Anosmia refers to the complete loss of olfactory capability, which can be a temporary disorder or a disorder affecting only the ability to perceive a particular scent, in which case the disorder would be termed a specific ansomia.
Oligo-: Prefix defining few.
Oncologist: A physician specialized in the diagnosis and treatment of cancer or tumour, as well as palliative care and therapy when cases warrant.
Oncology: The field of medicine devoted to the diagnostic, treatment and therapies for cancer and tumour.
Onycho-: Prefix defining a relationship to the nails.
Onychodystrophy: Deformation and/or discolouration of the nail, usually occurring as a result of chemotherapy cancer treatment.
Oogenesis: The process by which egg cells (ova) are created in the female.
Open Heart Surgery: Any surgery performed on the heart or its structures involving the opening of the chest.
Ophthalmia: Inflammation of the eye, which may occur as a result of trauma or injury; in response to prolonged exposure to UV rays; or as a symptom of a bacterial conjunctivitis. Also termed ophthalmitis.
Ophthalmic: Regarding the eye.
Ophthalmic Migraine: A migraine which induces only the visual aspects, often called migraine auras, associated with experiencing a migraine, but not the headache pain itself.
Ophthalmologist: A physician specialized in the diagnostics, treatment and surgery for conditions and disorders of the eye.
Ophthalmology: The field of medicine focuses in the structure, workings and diseases of the eye.
Ophthalmopathy: Protrusion of the eyes due to inflammation of the eye muscles, a condition occurring in many cases with Grave's disease.
Optics: The study of light, and often its association with vision.
Optic Glioma: A tumour of the optic nerve.
Optic Nerve: The nerve responsible for the transmission of visual information between the retina of the eye and the brain.
Optometrist: A health care professional qualified to provide examination, diagnosis and treatment for conditions and diseases of the eye, including glaucoma.
Oral: Regarding the mouth.
Oral Cancer: Cancer of the oral cavity; the mouth. Oral cancer may develop from tissues of the oral cavity itself or as a result of cancer metastasizing to the mouth from an adjacent or distant bodily site.
Oral Contraceptive: Birth control taken by mouth; the birth control pill.
Orchiectomy: The surgical process, usually performed by a urologist, by which one or both of the testes are removed, most often in response to suspected testicular cancer. If the individual should elect to do so, a prosthetic testicle can be inserted into the vacant scrotum.
Orchiopexy: A surgical procedure conducted, usually by a urologist, to bring an undescended testicle down into the scrotum and fix it in place.
Orchitis: Painful inflammation of the testes, usually occurring as a result of infection, such as chlamydia, or mumps.
Organ Failure: The failure of an organ to function as it is expected to. Multiple organ failure involves two or more organs, and can occur due to sepsis (blood poisoning, or systemic inflammatory response syndrome) as a result of infection.
Orifice: A natural opening or plate of the body, such as the mouth.
Ornithophobia: An abnormal fear of birds.
Ortho- dt>: Prefix defining straight.
Orthopedics: The study, diagnosis and treatment of conditions pertaining to the body's musculoskeletal system.
Orthopedist: A physician specialized in the diagnostics and treatment of conditions and disease of the musculoskeletal system, which includes the bones, tendons, ligaments, muscles, nerves and joints. Other orthopedic fields include physiotherapy, podiatry and occupational therapy.
Orthopnea: A breathing difficulty causing troubled breath patterns when lying flat, or sleeping. Individuals with orthopnea often must seek sleep in chairs or in an elevated position.
Orthotics: The medical field focused on the creation and application of orthopedic devices, or orthoses. Orthotics can include devices such as braces or splints that function to correct or secure a limb or torso unable to do so itself.
Ossicle: The tiny bones of the middle ear; the body's three smallest.
Ossification: The processes of creating bone tissue.
Osteitis: Bone inflamation.
Osteitis Fibrosa Cystica: A condition caused by an over-production of parathyroid hormone, which induces the activity of osteoclasts, which in turn breakdown bone tissue. Hyperparathyroidism may be induced by hereditary conditions, renal osteodystrophy or parathyroid carcinoma. Also called Von Recklinghausen's disease or osteodystrophia fibrosa.
Osteo-: Prefix defining a relationship with bone.
Osteoarthritis: The loss of cartilage and breakdown of joints, incited by a variety of hereditary, metabolic or other factors. May lead to muscle atrophy, fluid in the joints or exposed bone damage. Treatment includes pain relief, diet and exercise regimen. Also termed degenerative arthritis or degenerative joint disease.
Osteomalacia: The softening of bone, induced by bone mineralization, or the process where organic material becomes inorganic. Usually caused by a vitamin d definciency. In children, this condition is commonly called rickets. Osteomalacia may coincide with osteoporosis.
Osteomyelitis: Bone inflammation or bone marrow incited by infection.
Osteoporosis: A bone disease causing a decrease in bone mineralization, due to protein depletion in the bone. Osteoporosis has several causes, including estrogen deficiency and side effects from certain medications. Treatment includes calcium, bisphosphonate and vitamin D supplementation, as well as prevention of incidents that could result in bone fractures.
Osteosarcoma: One of the most common forms of cancer in children, osteosarcoma develops from primitive altered cells to form an aggressive, malignant neoplasm, usually in long bones such as the femur. Surgery and radiation therapy are the most common forms of treatment used to treat individuals with this type of bone cancer.
Otitis: Inflammation of the ear. Externa otitis is used to describe inflammation of the outer ear, otitis media inflammation of the middle ear, and otitis interna inflammation of the inner ear.
Oto-: Prefix defining a relationship to the ear.
Otolaryngologist: An ear, nose and throat specialist. Also referred to as an ENT physicians or head and neck surgeons.
Otology: A focus in bio-medicine on the physiology, functions, diagnostics and disease of the ear.
Otoplasty: A cosmetic surgical procedure conducted to reshape or correct the shape of the outer ear. This may include ear pinning, reshaping cartilage, or developing an ear where the ear was absent.
Ova: Eggs.
Ovarian: Regarding the ovary.
Ovarian Cancer: Cancer that develops in the tissues of the female ovaries. Risk tends to rise with age, decreases with pregnancies and also seems largely affected by possession of a mutated BRCA1 or BRCA2 gene. Prognosis improves with earlier detection.
Ovarian Pregnancy: An ectopic pregnancy (one that occurs outside of the cavity of the uterus) that takes place in the ovary itself. If the fertilized egg continues to develop and not be treated, fatal bleeding my occur.
Ovarian Teratoma: A tumour usually consisting of all three germ layers; hair, teeth and/or bone, as well as, in some rare cases, an organ such as a limb or eye.
Ovariectomy: The surgical removal of one or both ovaries, usually in response to a diagnosis of ovarian cancer. Also termed an oophorectomy.
Ovum: An egg in of the femal ovary.
Oxytocin: A hormone that acts as a neurotransmitter, especially prominent in inciting the female reproductive system to make various responses upon trigger, such as cervix distension amid labor.