Medical Dictionary

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ectental (ek-ten′tal)
Relating to both ectoderm and endoderm; denoting the line where these two layers join. SYN: ectoental. [G. ektos, outside, + entos, within]

ectethmoid (ekt-eth′moyd)
SYN: ethmoidal labyrinth. [G. ektos, outside, + ethmoid]

ecthyma (ek-thi′ma)
A pyogenic infection of the skin initiated by β-hemolytic streptococci and characterized by adherent crusts beneath which ulceration occurs; the ulcers may be single or multiple, and heal with scar formation. [G. a pustule] contagious e. SYN: orf. e. gangrenosum SYN: dermatitis gangrenosa infantum.

ectiris (ek-ti′ris)
The outer layer of the iris. [G. ektos, outside, + iris]

ecto-, ect-
Outer, on the outside. SEE ALSO: exo-. [G. ektos, outside]

ectoantigen (ek-to-an′ti-jen)
Any toxin or other excitor of antibody formation, separate or separable from its source. SYN: exoantigen.

ectoblast (ek′to-blast)
1. SYN: ectoderm. 2. As used by some experimental embryologists, the original outer cell layer from which the primary germ layers are formed; in this sense, synonymous with epiblast. 3. A cell wall. [ecto- + G. blastos, germ]

ectocardia (ek-to-kar′de-a)
Congenital displacement of the heart. SYN: exocardia. [ecto- + G. kardia, heart]

ectocervical (ek′to-ser′vi-kal)
Pertaining to the vaginal part of the cervix of the uterus lined with stratified squamous epithelium.

ectochoroidea
SYN: suprachoroid lamina of sclera.

ectocornea (ek-to-kor′ne-a)
The outer layer of the cornea.

ectocrine (ek′to-krin)
1. Relating to substances, either synthesized or arising by decomposition of organisms, that affect plant life. 2. A compound with e. properties. 3. An ectohormone. Cf.:endocrine, exocrine. [ecto- + G. krino, to separate] ecological e. a chemical substance that undergoes biosynthesis in one species and that exerts an effect on the function of another species through mechanisms of the external environment; e.g., the biosynthesis of vitamins by ruminants and their subsequent ingestion by other animals. SEE ALSO: ectohormone.

ectocyst (ek′to-sist)
The outer layer of a hydatid cyst. [ecto- + G. kystis, bladder]

ectoderm (ek′to-derm)
The outer layer of cells in the embryo, after establishment of the three primary germ layers (e., mesoderm, endoderm), the germ layer in contact with the amnionic cavity. SYN: ectoblast (1) . [ecto- + G. derma, skin] amnionic e. inner layer of the amnion continuous with body e.. chorionic e. SYN: trophoblast. epithelial e. that part of the e. separating from the neuroectoderm at about the fourth week of embryonic life; the epidermis and its specialized derivatives develop from it. SYN: superficial e.. extraembryonic e. derivative of epiblast outside the embryo's body. superficial e. SYN: epithelial e..

ectodermal (ek-to-der′mal)
Relating to the ectoderm. SYN: ectodermic.

ectodermatosis (ek′to-der-ma-to′sis)
SYN: ectodermosis.

ectodermic (ek-to-der′mik)
SYN: ectodermal.

ectodermosis (ek′to-der-mo′sis)
A disorder of any organ or tissue developed from the ectoderm. SYN: ectodermatosis.

ectoentad (ek-to-en′tad)
From without inward.

ectoental (ek-to-en′tal)
SYN: ectental.

ectoenzyme (ek-to-en′zim)
1. An enzyme that is excreted externally and that acts outside the organism. 2. An enzyme that is attached to the external surface of the plasma membrane of a cell.

ectoethmoid (ek-to-eth′moyd)
SYN: ethmoidal labyrinth.

ectogenous (ek-toj′e-nus)
SYN: exogenous. [ecto- + G. -gen, producing]

ectohormone (ek′to-hor-mon)
A parahormonal chemical mediator of ecologic significance which is secreted, largely by an organism (usually an invertebrate) into its immediate environment (air or water); it can alter the behavior or functional activity of a second organism, often of the same species as that secreting the e.. SEE ALSO: ecological ectocrine.

ectomere (ek′to-mer)
One of the blastomeres involved in formation of ectoderm. [ecto- + G. meros, part]

ectomerogony (ek′to-me-rog′o-ne)
The production of merozoites in the asexual reproduction of sporozoan parasites at the surface of schizonts and of blastophores, or by infolding into the schizont, as contrasted with endomerogony; e. has been observed in various species of Eimeria. [ecto- + G. meros, part, + gone, generation]

ectomesenchyme (ek-to-mes′en-kim)
SYN: mesectoderm (2) . [ecto- + G. mesos, middle, + enkyma, infusion]

ectomorph (ek′to-morf)
A constitutional body type or build (biotype or somatotype) in which tissues originating from the ectoderm predominate; from a morphological standpoint, the limbs predominate over the trunk. SYN: longitype. [ecto- + G. morphe, form]

ectomorphic (ek-to-morf′ik)
Relating to, or having the characteristics of, an ectomorph.

-ectomy
Removal of an anatomical structure. SEE ALSO: -tomy. [G. ektome, a cutting out]

ectopagus (ek-top′a-gus)
Conjoined twins in which the bodies are joined laterally. See conjoined twins, under twin. [ecto- + G. pagos, something fixed]

ectoparasite (ek-to-par′a-sit)
A parasite that lives on the surface of the host body.

ectoparasiticide (ek′to-par-a-sit′i-sid)
An agent that is applied directly to the host to kill ectoparasites. [ectoparasite + L. caedo, to kill]

ectoparasitism (ek′to-par′a-si-tizm)
SYN: infestation.

ectoperitonitis (ek′to-par-i-to-ni′tis)
Inflammation beginning in the deeper layer of the peritoneum which is next to the viscera or the abdominal wall.

ectophyte (ek′to-fit)
A plant parasite of the skin. [ecto- + G. phyton, plant]

ectopia (ek-to′pe-a)
Congenital displacement or malposition of any organ or part of the body. SYN: ectopy, heterotopia (1) . [G. ektopos, out of place, fr. ektos, outside, + topos, place] e. cloacae SYN: cloacal exstrophy. e. cordis congenital condition in which the heart is exposed on the chest wall because of maldevelopment of the sternum and pericardium. crossed renal e. ectopic kidney located on opposite (contralateral) side of midline from its ureteral insertion into bladder. In most instances, the two renal moieties are fused (crossed fused e.). crossed testicular e. testis that has crossed the midline to join its contralateral mate in the contralateral inguinal canal or hemiscrotum. e. lentis displacement of the lens of the eye. SYN: dislocation of lens. e. lentis et pupillae disorder characterized by corectopia and a subluxed or dislocated lens. e. maculae a condition in which one macula is displaced so that the two foveas are not at corresponding retinal points. SYN: heterotopia maculae. e. pupillae congenita displacement of the pupil present at birth. e. renis displacement of the kidney. e. testis SYN: testis e.. testis e. testis that is malpositioned other than along the normal path of descent. SYN: e. testis, parorchidium. thoracoabdominal e. cordis SYN: pentalogy of Cantrell. ureteral e. abnormal termination of ureter within the bladder, the urethra, or outside the urinary tract. e. vesicae SYN: exstrophy of the bladder.

ectopic (ek-top′ik)
1. Out of place; said of an organ not in its proper position, or of a pregnancy occurring elsewhere than in the cavity of the uterus. SYN: aberrant (3) , heterotopic (1) . 2. In cardiography, denoting a heartbeat that has its origin in some abnormal focus; developing from a focus other than the sinoatrial node. [see ectopia]

ectoplacental (ek′to-pla-sen′tal)
1. Outside, beyond, or surrounding the placenta; in primates, referring especially to the parts of the trophoblast not directly involved in the formation of the placenta. 2. In rodents, referring to the actively growing part of the trophoblast involved in the formation of the placenta.

ectoplasm (ek′to-plazm)
The peripheral, more viscous cytoplasm of a cell; it contains microfilaments but is lacking in other organelles. SYN: exoplasm. [ecto- + G. plasma, something formed]

ectoplasmatic, ektoplasmic, ektoplastic (ek-to-plas-mat′ik, -plas′mik, -plas′tik)
Relating to the ectoplasm.

ectopy (ek′to-pe)
SYN: ectopia.

ectoretina (ek′to-ret′i-na)
SYN: pigmented layer of retina.

ectosarc (ek′to-sark)
The outer membrane, or ectoplasm, of a protozoon. [ecto- + G. sarx, flesh]

ectoscopy (ek-tos′ko-pe)
An obsolete method of diagnosis of disease of any of the internal organs by a study of movements of the abdominal wall or thorax caused by phonation. [ecto- + G. skopeo, to examine]

ectosteal (ek-tos′te-al)
Relating to the external surface of a bone. [ecto- + G. osteon, bone]

ectostosis (ek-tos-to′sis)
Ossification in cartilage beneath the perichondrium, or formation of bone beneath the periosteum. [ecto- + G. osteon, bone, + -osis, condition]

ectothrix (ek′to-thriks)
A sheath of spores (conidia) on the outside of a hair. [ecto- + G. thrix, hair]

ectotoxin (ek-to-tok′sin)
SYN: exotoxin.

ectozoon (ek-to-zo′on)
An animal parasite living on the surface of the body. [ecto- + G. zoon, animal]

ectro-
Congenital absence of a part. [G. ektrosis, miscarriage]

ectrocheiry, ectrochiry (ek-tro-ki′re)
Total or partial absence of a hand. [ectro- + G. cheir, hand]

ectrodactyly, ectrodactylia, ectrodactylism (ek-tro-dak′ti-le, -dak-til′i-a, -dak′ti-lizm)
Congenital absence of all or part of one or more fingers or toes. There are several varieties and the pattern of inheritance may be autosomal dominant with reduced penetrance [MIM*183600 and MIM*183802], autosomal recessive [MIM*225290 and MIM*225300], or X-linked [MIM*313350]. [ectro- + G. daktylos, finger]

ectrogenic (ek-tro-jen′ik)
Relating to ectrogeny.

ectrogeny (ek-troj′e-ne)
Congenital absence or defect of any bodily part. [ectro- + G. -gen, producing]

ectromelia (ek-tro-me′le-a)
1. Congenital hypoplasia or aplasia of one or more limbs. 2. A disease of mice caused by the e. virus, a member of the family Poxviridae; characterized by gangrenous loss of feet and necrotic areas in the internal organs; in laboratory mouse colonies, it usually results in high mortality rates. [ectro- + G. melos, limb]

ectromelic (ek-tro-mel′ik)
Pertaining to, or characterized by, ectromelia.

ectropion, ectropium (ek-tro′pe-on, -pe-um)
A rolling outward of the margin of a part, e.g., of an eyelid. [G. ek, out, + trope, a turning] atonic e. e. of the lower eyelid following paralysis of the orbicularis oculi muscle. SYN: flaccid e., paralytic e.. cicatricial e. e. of the eyelids after burns, lacerations, or skin infection. flaccid e. SYN: atonic e.. paralytic e. SYN: atonic e.. spastic e. e. of the lower eyelid as a result of ocular irritation and/or orbicularis oculi muscle contraction. e. uveae eversion of the pigmented posterior epithelium of the iris at the pupillary margin.

ectropody (ek-trop′o-de)
Total or partial absence of a foot. [ectro- + G. pous, foot]

ectrosyndactyly (ek′tro-sin-dak′ti-le)
Congenital abnormality marked by the absence of one or more digits and the fusion of others. [ectro- + G. syn, together, + daktylos, finger]

ectylurea (ek′til-u-re′a)
A mild obsolete sedative used in the treatment of nervous tension and anxiety.

ectype (ek′tip)
Extreme somatotype, such as ectomorph (longitype) or endomorph (brachytype). [G. ek, out, + typos, stamp, model]

ecuresis (ek-u-re′sis)
A condition in which urinary excretion and intake of water act to produce an absolute dehydration of the body. SEE ALSO: emuresis. [G. ek, out, + ouresis, urination]

eczema (ek′ze-ma, eg′ze-ma, eg-ze′ma)
Generic term for inflammatory conditions of the skin, particularly with vesiculation in the acute stage, typically erythematous, edematous, papular, and crusting; followed often by lichenification and scaling and occasionally by duskiness of the erythema and, infrequently, hyperpigmentation; often accompanied by sensations of itching and burning; the vesicles form by intraepidermal spongiosis; often hereditary and associated with allergic rhinitis and asthma. [G. fr. ekzeo, to boil over] allergic e. macular, papular, or vesicular eruption due to an allergic reaction, e.g., contact dermatitis. atopic e. SYN: atopic dermatitis. baker e. allergic e. due to contact with flour, yeast, or other ingredients handled by bakers. chronic e. SYN: lichenoid e.. dyshidrotic e. SYN: dyshidrosis. e. erythematosum a dry form of e. marked by extensive areas of redness with scaly desquamation. flexural e. e. of skin at the flexures of elbow, knees, wrists, etc., associated with atopy persisting through childhood. hand e. e. that predominantly and persistently affects the hands; of multiple causation, including allergic, industrial, irritant, dyshidrotic, bacterial, and atopic mechanisms; distinguished from chapped hands by the presenc of vesiculation or spongiosis. e. herpeticum a febrile condition caused by cutaneous dissemination of herpesvirus type 1, occurring most commonly in children, consisting of a widespread eruption of vesicles rapidly becoming umbilicated pustules; clinically indistinguishable from a generalized vaccinia. The two may be distinguished by electron microscopy or demonstration of inclusion bodies in smears, which are intranuclear in e. herpeticum and intracytoplasmic in e. vaccinatum. SYN: pustulosis vacciniformis acuta. infantile e. e. in infants; the clinical appearance varies according to the dominant causative mechanism, e.g., contact-type hypersensitivity, candidiasis, atopy, seborrhea, or a combination including intertrigo and diaper dermatitis. e. intertrigo intertrigo. lichenoid e. thickening of skin with accentuated skin lines in e.. SYN: chronic e.. nummular e. discrete, coin-shaped patches of e.. SYN: nummular dermatitis. e. papulosum a dermatitis marked by an eruption of discrete or aggregated reddish excoriated papules. e. parasiticum eczematous eruption precipitated by parasite infestation. e. pustulosum a later stage of vesicular e., in which the vesicles have become secondarily infected; the lesions become covered with purulent crusts. seborrheic e. SYN: seborrheic dermatitis. stasis e. eczematous eruption on legs due to or aggravated by vascular stasis. tropical e. e. occurring in plaques on extensors of the extremities; of common occurrence and unknown etiology. e. tyloticum hyperkeratotic dyshidrosis. varicose e. e. occurring over areas in which the skin has been compromised by varicosities. e. verrucosum e. with hyperkeratosis; chronic lichenified e.. e. vesiculosum dermatitis marked by an eruption of vesicles upon erythematous patches that rupture and exude serum. weeping e. a moist, eczematous dermatitis. winter e. e. resulting from accelerated evaporation of moisture (including insensitive sweat) from the cutaneous surface; occurs as dry crackled plaques, usually on the extremities, but not infrequently also on the trunk in any season under circumstances (occupational, environmental) of excessively rapid drying out of the skin.

eczematization (ek-zem′a-ti-za′shun)
1. Formation of an eruption resembling eczema. 2. Occurrence of eczema secondary to a preexisting dermatosis.

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