Habenula - diminutive of Latin habena = rein.

Haemorrhoid - Greek haima = blood, and rhoia = to flow, hence likely to bleed.

Hallucis - (L. hallux, great toe). The muscles and tendons associated with the first digit of the foot.

Hallux - Latin hallex = great toe (hallucis = of the great toe).

Hamate - adjective, Latin hamus = a hook, hence, hooked.

Hamstrings - the tendons of the muscles of the ham - i.e. of the back of the thigh - felt behind the knee when the leg is flexed against resistance (semimembranosus, semitendinosus and biceps femoris).

Hamulus - diminutive of Latin hamus = hook.

Haustra - Latin = saccules.
 
Heart rate (hr) - the number of heartbeats per minute.

Heent - A standard abbreviation for Head, Eyes, Ears, Nose, and Throat.

Helicine - Greek helix = a coil, spiral.

Helicotrema - Greek helix = a coil, and trema = hole, hence the aperture at the apex of the bony cochlea whereby scala vestibuli communicates with scala tympani.

Helix - Greek = coil.

Hematocrit - Hematocrit is the percentage of the volume of a blood sample occupied by cells, as determined by a centrifuge or device which separates the cells and other particulate elements of the blood from the plasma. The remaining fraction of the blood sample is called plasmocrit (blood plasma volume).

Hematogenous - Originating in the blood or spread through the bloodstream.

Hematologic - Of or relating to blood or to hematology.

Hemianopia - Greek hemi = half, an = negative, opsis = vision, hence loss of half of the field of vision.

Hemianopsia - Greek hemi = half, an = negative, opsis = vision, hence loss of half of the field of vision.

Hemigastrectomy - Excision of the distal one-half of the stomach.

Hemiparesis - Greek hemi = half, paresis = paralysis, used usually to denote weakness rather than paralysis.

Hemiplegia - Greek hemi = half, plegia = stroke, hence, paralysis of one half of the body.

Hemisphere - Greek hemi = half, sphaira = ball, hence, half of a sphere.

Hemopoiesis - the process that produces the formed elements of the blood and takes place in the red bone marrow of long bones.

Hemorrhage - A copious discharge of blood from the blood vessels.

Hemostasis - the stoppage of bleeding through vascular spasm, platelet plug, or coagulation.

Hemotopoiesis (adj. hematopoietic) - The formation of blood or of blood cells in the living body.

Henry's law - the greater the partial pressure of a gas, the greater the diffusion of the gas into the liquid.

Hepar - Greek = liver, adjective - hepatic.

Heparin - A drug given directly into a vein that thins the blood when there is a danger of clotting (an anticoagulant)

Hepatic - adjective, Greek hepar = the liver.

Hepatic flexure - The hepatic flexure is situated between the ascending and the transverse part of the colon, beneath the liver.

Hepatocyte - An epithelial cell of the liver responsible for the synthesis, degradation, and storage of a variety of materials.

Hernia - The bulging of an internal organ through a weak area or tear in the muscle or other tissue that holds it in place. Most hernias occur in the abdomen. Latin = a protrusion, adjective - hernial.
 
Hiatal Hernia - A type of hernia that occurs when a portion of the stomach protrudes through the diaphragm (where the oesophagus normally passes through).

Hiatus - Latin = a gap (like that between some people's ears).

Hilum - A notch in or opening from a bodily part suggesting the hilum of a bean.
 
Hindbrain - the part of the brain below tentorium cerebelli, comprising medulla oblongata, pons and cerebellum.

Hip - the lateral prominence of the hip bone and greater trochanter.

Hippocampus - Greek hippokampos = a sea-horse, hence, the curled shape of the hippocampus in coronal section; adjective - hippocampal.

Histamine - Histamine is a chemical present in cells throughout the body that is released during an allergic reaction. Histamine is one of the substances responsible for the symptoms on inflammation and is the major reason for running of the nose, sneezing, and itching in allergic rhinitis. It also stimulates production of acid by the stomach and narrows the bronchi or airways in the lungs.

Histology - the study of tissues at the microscopic level.

Hodgkin lymphoma - Lymphoma is a cancer of the lymphatic system - the network of lymph glands and channels which occurs throughout the body.

Hodgkin's disease - Hodgkin's disease, or Hodgkin's lymphoma, is a cancer of the lymphatic system. There are two main types of lymphoma: Hodgkin's and non-Hodgkin's. The presence of Reed-Sternberg cells is diagnostic of Hodgkin's lymphoma and distinctly separates the Hodgkin's lymphomas from the non-Hodgkin's lymphomas.

Hofmeister-finsterer operation - Partial gastrectomy with closure of a portion of the lesser curvature and retrocolic anastomosis of the remainder to the jejunum.

Homeostasis - the maintenance of stable, internal conditions within specific limits. A characteristic of all living systems.

Homologous - adjective, Greek homos = same, and logos = word, hence a part with similar morphology but different function.

Horizontal - adjective - parallel to the horizon.

Horizontal (transverse) plane - divides the body or organ horizontally into a top and bottom part.

Hormonal therapy - Treatment of cancer by alteration of the hormonal balance. Some cancer will only grow in the presence of certain hormones.

Hormone - chemical messenger produced by a cell that effects specific changes in the cellular activity of other cells.

Horn - a projection, often pointed.

Hsm - A standard medical abbreviation for Hepato Spleno Megaly (hepatosplenomegaly) -- HSM = enlarged liver (hepato) and enlarged spleen (spleno).

Humero - (G. homos, shoulder). Pertaining to the bone of the arm and a muscles associated with it.

Humerus - Latin = the arm-bone.

Humour - Latin humor = liquid, hence the aqueous and vitreous humour of the eyeball.

Hyaline - adjective, Greek hyalos = glassy. Transparent or nearly so and usually homogeneous.
 
Hydatidiform mole - In human pregnancy, abnormal growth of the chorion, the outermost vascular membrane that in a normal pregnancy would enclose the embryo and ultimately give rise to the placenta. In the situation in which the hydatidiform mole develops, the embryo is usually either absent or dead.

Hydrocephalus - Greek hydor = water, koilos = head. (cf. cephalic).

Hydrogen bond - a weak chemical bond that forms between the positively charged hydrogen atom and one covalently bonded molecule and the negatively charges area of another covalently bonded molecule.

Hymen - Greek = membrane; across the virginal vagina.

Hyo - (G. hyoeides, hyoid). Relating to the U-shaped hyoid bone and muscles associated with it.

Hyoid - adjective, Greek = U-shaped.

Hyoideus - See Hyo- above.

Hyperacusis - Greek hyper = over, and akousis = hearing, hence excessive sensitivity to sound.

Hypochromic anemia - Anemia characterized by a decrease in the concentration of corpuscular hemoglobin.

Hypodermis - The layers beneath the epidermis, comprising thick-walled sclerenchymatous cells. The layer between the dermis and the underlying tissues and organs.

Hypoglossal - adjective, Greek hypo = under, and glossa = tongue.

Hypophysis - Greek hypo = down, physis = growth, hence, a downgrowth (from the brain). However, this is not the whole truth. Part is an upgrowth from the pharynx, adjective - hypophysial.

Hypothalamus - Greek hypo = under, and thalamus (q.v.), refers to part of diencephalon.