IN r 



mnA-Tcs, and they are covered behind by the lon^ffimus 

 dorfi and facrolumbalis ; above and below they are fixed to 

 the traiifverfe procefles. They produce the lateral inflexions 

 of thedorfal vertebrs. 



Iniertranfverfi lumborum, tranfverfaires des lombes. Thefe 

 are fmall mufcuiar planes friling the intervals between the 

 ti-anfverfe procefles of the lumbar vertebra. Their number 

 is five, the firll beiiijr placed between the lad dorlal and the 

 firll lumbar vertebra, and the lad between the fourth and 

 nftli lumbar vertebrx. They are thin, flattened, and quadri- 

 lateral. They correfpond in front to the qiiadratus lumbo- 

 rumj and behind, to the facrolun-.balis ; their upper and 

 lower edges are fixed to the tranfverfe procefles. They are 

 almoft entirely flclhy. Their office is that of inclining the 

 vertebral column towards one fide, or of relloring it to the 

 ereft (late after it has been fo inclined. 



INTERTRIGO, in Medkme, ■^c,.'xr^.^f^x of the Greeks, 

 fignifies an erythematous aixeftion of the flcin, a fmooth, 

 fliining reJnefs and tendernefs of the part, chiefly from 

 frittion. 



The Intertrigo moft commonly arifes in thofe parts of the 

 furface, wliich lie in contact with each other, and are liable 

 therefore to confiderable attrition during motion ; or in thofe 

 which are fubjeCt to friftion and prefTure from other caufes ; 

 and more efpecially when, at the fame time, any acrid fluid 

 is prefent. Whence it is very frequent about the top of the 

 thighs and the perineum of infants, when the cloths in which 

 they are wrapped become wetted with the urine. Similar 

 affcdlions of the fltin are alfo liable to occur in perfons who 

 take exercife on horfeback, or in the feet of thofe who have 

 walked a confiderable diflance, efpecially in tight flioes, and 

 in the backs and (boulders of fick perfons, long confined to 

 bed. The firft of thefe varieties, which occur in the /i/ic* or 

 duplicatures of the fliin, or originate from the attrition of 

 the bandages impregnated with urine, &c. Sauvages has 

 called Erythema Intertrigo ; the latter from friction of the 

 clothes, or bed, he denominates Erythema paratrimma. 

 See his Nofol. Method. Clafs i. Genus 1 1, fpec. 5and6. 

 . Dr. Willan alfo treats of the former varieties of the 

 diforder under the fame head. When fpeaking of erythema, 

 he fays, we may rank under tiie prefent article that fpecies 

 of intertrigo which is produced in fome perfons by the attri- 

 tion of contiguous furfaces, as beneath the breafts, round 

 the axillje, in the groin, and at the upper part of the thighs, 

 and is attended with a glairy and fetid fecretion. The in- 

 tertrigo is moil troublefome when it affects the thighs ; it 

 commences where they are in contact wnth the fcrotiun, and 

 extends upwards to the groin and nates, round the fcrotum, 

 and down the iioUow of the thigh. In places where the 

 friftion is llrongeft, the rednefs is continuous, but it ter- 

 minates at the edges in a mixed colour, fuch as characterizes 

 cn5orefcences generally. This complaint is moll frequent 

 in very warm weather, and affects perfons of the fanguine 

 temperament, efpecially thofe who are corpulent. It fome- 

 times terminates in the prurigo, or pforiafis fcrotaHt. An ap- 

 pearance analogous to the intertrigo, is produced by acri- 

 monious dilcharges in perlons labouring under dyfentery, 

 gonorrhrea, &c. ; in females affcfted with fluor albus, or 

 uterine fiirrhus, and in infants, from the ilimulus <f the 

 ■ >«rine. See. with which their clothes are almoft conl'cautly 

 wetted. (See Willan on Cutaneous Difeafes, p. 48 1.) 

 He rcfufes to clafs thi.s morbid Hate otthe (kin with excoria- 

 tion, or fiiperficial ulceration, as fevt-ral writers both ancient 

 and modern have done; and therefore excludes from the in- 

 tertrigo th'.>fe excoriations included in the 6th fpecies, or 

 Erythema paratrimma, of Sauvage.s. 



Freq .tnt ablution with tepid water is necefl"ary to allay 



I N T 



the heat and uneafrnifs which attend this eomplalnt, to re- 

 move the vifcid fecretion from the furface, and to prevent 

 excoriation. \\'Tien the fkin is fretted by the difcharge of an 

 acrimonious fluid, fome relief is obtained by the application 

 of dry abforbent powders ; in cafe of Jibrafion and fifTures, 

 the elder-ointment may be applied witli much advantage. 



INTERTWISTED Suture. See Suture. 



INTERVAL, th.- diftance or fpace between two ex- 

 tremes, cither in time or place. 



The word comes from the Latin intervallum, which, ac- 

 cording to Isidore, fignifies the fpace inter fojfam et murum, 

 between the ditch and the wall : others note, that the flakes 

 or piles, driven into the ground in the ancient Roman bul- 

 warks, were called -va/Za, and the interftices or vacancy 

 between them iniervella. 



Interval, Angle of. See Angle. 



Intervals, Lucid. See Lucid. 



Interval, in Mufic, the difference between two founds, 

 in refpect of acute a-.id grave ; or that imaginary fpace ter- 

 minated with two founds differing in acutenefs or gravity. 

 When two or more founds are comjiared in this relation, 

 they are either equal or unequal in the degree of tunc : fuch 

 as are equal ai-e called uvjfons, with regard to each other, as 

 having one tune ; the other, beirtg at a diitancc from each 

 other, conilitute what we call an interval in mufic ; which is 

 properly the diftance in tune between two founds. 



Intervals are diilinguifhed into Jimple si^d compound. 



Interval, Simple, is that without parts, or divifion : 

 fuch are the oftave, and a 1 that are witliin it ; as the 

 fecond, third, fourth, fifth, fi.'cth, and fcventh, with their 

 varieties. 



IntesvaL, Compound, confifts of feveral lefler intervals : 

 fuch are all thofe greater than the o£tave; as the ninth, 

 tenth, eleventh, twelfth, &c with their varieties. But this 

 dillinftion, it is to be oljferved, regards practice only, be- 

 caufe there is really no fuch thing as a leaft interval. Be- 

 fides, by Ajimple interval is not meant here the leaft prac- 

 tiled, but fuch as though it were equal to tv.o or more leffer, 

 which are in life, yet when wc would make a found move fo 

 far up or down we always pafs immediately from one of its 

 terms to the other. What is meant tlien by a compound in- 

 terval will be very plain : it is fuch, whofe terms are in prac- 

 tice taken either in immediate fucccffion, or fuch where the 

 found is made to rife and fall from the one to the other, by 

 touching fome intermediate degree ; f»- that the whole be- 

 comes a compofiti:;n of ail the intervals from one extreme to 

 the other. 



What we here cill ajimp/e interval, the ancients called a 

 diajlan, and the compound they call a/y/2 m. 



Each of thefe hid its diflerenccs ; even of the fimple 

 there are fome greater, and others lefs : but they are always 

 difc!)rd ; but of the compound, or fyliems, fome are con- 

 cord, othi-rs difcord. Unifons, it is plain, cannot pofTibly 

 have any variety ; for where there is no nifference, ns in uni- 

 fonance, which ilow.s from a relation of equality, it is plain 

 there can be no diilinction : unilons 'herefore muft ail be 

 concords. But an interval depending on a difference of 

 tune, or a relation of inequality, admi s of variety ; and fo 

 the terms of every interval, according to their particular re- . 

 lation or difference, make either concord or difcord. Some 

 indeed have re 'Gained the word concord to ii:tervals, making 

 it include a difference in tune : but this is precarious ; for as 

 the word co. cord tigiiiiies an agreement of founds, it is cer- 

 tainly applicable to unilons in the firll degree. Intervals, it 

 is plain, may d tfcr in magnitude, and there may be an infi- 

 nite variety, accordiiig to the poffible degree of tune ; tor 

 there is no difference fo great or fo little, but a greater or a 



kf» 



