2,701 articles
Blue field entoptic phenomenon
Blue field entoptic phenomenon, or Scheerer's phenomenon: bright moving dots seen against blue sky, caused by white blood cells passing through macular retinal capillaries; used to measure macular blood flow.
Blunt splenic trauma
Blunt splenic trauma: spleen injury from non-penetrating force, also called blunt splenic injury. Non-operative management is standard in hemodynamically stable patients; failure under 10% overall, up to 75% in grade V; splenic artery embolization is the key adjunct.
Body cavity
Body cavity: the fluid-filled internal spaces of animals, including the coelom (mesoderm-lined cavity) and the human dorsal and ventral cavities (cranial, spinal, thoracic, abdominopelvic) with their serous membranes and embryonic origin.
Body Constitution
Body constitution is a medical concept covering a person's whole physical makeup: metabolic processes, reactions to stimuli, disease resistance, and predispositions studied in physical examination.
Body Fat Distribution
Body fat distribution, also called body fat patterning, is the regional pattern of adipose tissue deposits. Android (abdominal) fat carries higher cardiometabolic risk than gynoid (hip-thigh) fat; measured by WC, WHR, WHtR, and imaging.
Body fluid
Body fluid: all water-based liquids in the body, in intracellular (about two-thirds) and extracellular (interstitial, plasma, transcellular) compartments; humans are 50-60% water as adults, regulated by osmosis and sodium balance.
Body hair
Body hair: hair from follicles covering nearly all human skin except lips, palms, and soles. Types are lanugo, vellus, and androgen-driven terminal hair; about 5 million follicles; excess growth is hirsutism or hypertrichosis.
Body shape
Body shape: the form and fat/muscle distribution of the human body, also called somatotype (Sheldon's endomorph, mesomorph, ectomorph). Measured by BMI, waist circumference, WHR, WHtR, ABSI; fat distribution affects cardiometabolic risk and varies by ancestry.
Body surface area
Body surface area (BSA) is the total surface area of the human body, usually estimated from height and weight and used for drug dosing and burn assessment.
Body Temperature
Body temperature: the heat measure of the human body, with core temperature regulated by the hypothalamus at roughly 36.5–37.5 °C. Covers Wunderlich's 37 °C standard, site-specific normal values, and peripheral thermometer accuracy.
Body water
Body water, also known as total body water, is the water contained in a living organism, averaging about 60% of body weight in adult men and 50% in women.
Bombesin
Bombesin is a 14-amino-acid peptide isolated from the skin of the European fire-bellied toad Bombina bombina in 1971 by pharmacologist Vittorio Erspamer, now the standard scaffold for imaging GRP-receptor-expressing tumors.
Bone
Bone: hard mineralized skeletal tissue of collagen and calcium phosphate, with cortical and trabecular types, remodeled by osteoblasts, osteoclasts, and osteocytes; stores calcium and marrow.
Bone cell
Bone cells are the specialized cells of bone tissue: osteoblasts (bone-forming), osteoclasts (resorbing), osteocytes (embedded mechanosensors, ~95% of bone cells), and bone lining cells, coordinated through RANKL/OPG and sclerostin signaling.
Bone Development
Bone development is the growth of bones from fetus to adult, through intramembranous and endochondral ossification, with growth plates driving lengthening and remodeling continuing throughout life.
Bone marrow
Bone marrow is the soft tissue inside bones that makes red and white blood cells and platelets; red marrow performs hematopoiesis, yellow stores fat, and donated marrow or peripheral-blood stem cells treat leukemia and other blood cancers.
Bone Remodeling
Bone remodeling: continuous osteoclast resorption and osteoblast formation of bone in basic multicellular units, in four phases, regulated by RANKL/RANK/OPG; measured clinically via PINP and β-CTX-I turnover markers.
Bone resorption
Bone resorption: osteoclasts dissolve bone mineral and matrix via acid and cathepsin K, regulated by RANKL/RANK/OPG; tracked by CTX and NTX markers and suppressed by bisphosphonates and denosumab.
Bowman's capsule
Bowman's capsule, the glomerular capsule, is the double-walled epithelial sac at the nephron's start that surrounds the glomerulus; its podocyte and parietal layers enclose Bowman's space where blood filtrate collects.
BOX trial
The BOX trial was a Danish randomized trial testing blood pressure and oxygen targets, plus fever prevention, in comatose survivors of out-of-hospital cardiac arrest, finding no benefit from higher targets.
Brachial plexus
Brachial plexus: nerve network from C5–T1 anterior rami supplying the upper limb, organized as roots, trunks, divisions, cords, and five terminal branches; variants, injuries, imaging, and reconstruction are covered.
Brachial plexus injury
Brachial plexus injury: damage to the C5-T1 nerve network serving shoulder, arm, and hand, from trauma, birth traction, gunshot, or tumor. Surgery timing under 6 months and nerve transfers improve recovery.
Brachial plexus palsy in newborn
Neonatal brachial plexus palsy (Erb's palsy, obstetric brachial plexus injury) is flaccid arm paralysis in newborns from C5–T1 nerve injury during birth; incidence about 1.7 per 1000, mostly upper-trunk, often recovering spontaneously.
Brachialis muscle
Brachialis (Musculus brachialis): fusiform elbow-flexor muscle of the anterior arm compartment, deep to biceps brachii; originates on distal anterior humerus, inserts on ulna, innervated mainly by musculocutaneous nerve.
Brachiocephalic artery
Brachiocephalic artery (innominate artery, brachiocephalic trunk): first branch of the aortic arch, dividing near the right sternoclavicular joint into the right common carotid and right subclavian arteries, supplying the right head, neck, and arm.
Brachioradialis
Brachioradialis: superficial lateral forearm muscle, formerly supinator longus, flexing the elbow best in mid-pronation; radial nerve (C5-C6), radial recurrent artery, C6 reflex, Wartenberg's syndrome.
Brachycephaly
Brachycephaly: a short, broad skull shape with flattened occiput, from anthropology's cranial index. In infants it is positional (20-50% US prevalence) or synostotic (bicoronal craniosynostosis); also seen in brachycephalic domestic breeds.
Bradycardic cardiac arrest
Bradycardic cardiac arrest: arrest reached through severe bradycardia or bradyasystole, usually from hypoxia or asphyxia rather than primary dysrhythmia; covers thresholds, atropine and pacing management, and survival by rhythm.
Bradyphrenia
Bradyphrenia, also called mental slowness, is slowed thinking and cognitive processing, coined by Naville in 1922 for post-encephalitic parkinsonism and now coded ICD-11 MB23.3, most often linked to Parkinson's disease.
Brain
The brain: three-pound central nervous system organ governing intelligence, senses, movement, and behavior; protected by skull, meninges, and blood-brain barrier; NINDS studies over 600 neurological diseases affecting some 100 million Americans.