SOLUCIONES Y EFECTOS NO DESEADOS

tor photography _ot lateral view ot the sheep.

2. View taken � .!!!

The camera was fixed t tb.e same height as and tbe d�stanee from the camera t o a l ine on Which the fore feet ot the animals placed, s shown in Figure 8 , s

1 6

feet.

<1

I 0

1 6

Pig. 8 . --Line diagram showing camera set-up for photography of frontal view of the she e p .

3. Dorsal

.!!.!!

taken

S: ill

T he c amera was fixed on a large tripo� T he vertic al c amera t o ground distance wa s 73i inc hes. S ince t he di ff erenc e

between "t he shortest and t he hi ghest animal in hei g ht at withers was not more than t hre e inc hes , l i t tle error was intr oduc ed by the fac t t ha t one sUb j ec t would be a little closer t o the camera

than would anothe r. The greatest error in t his v iew c anes

from not being able to plac e all the animals in exac tly the same

·-:.. -

-43-

E. Pluorosc opy and Radiographf of the Live Animals.

An attempt was made to view the limb b ones of the thoracic reg i on

(

scapulae , humeri and radi i-ulnae

)

of t he live animal by means of the f luorosc opic attac hment to t he X-r y plant . The ttempt was unsuccessful f or two r easons. Firstly , i t was aot possible to g t the c omplete darknes s re quired f or best results ; and sec ondly , the region of the t horax i s too thic k t o get a good image on t he screen even when the x-ray plant was turned up to the max� safe MA

(

milliamperes

)

f or fluorosc opy wi th the plant used. The rib could be pic ked out , but the b on s of the limb s presented only dark, fuzzy-edged blobs. This region is the thickest on t he animal as tar as bone i s c oncerned, since there are two layers of bones or th thorac ic walls s we ll as t he two set s of limb bones.

In order to ke p t he animals c lose against the x-ray

plate whic h was kept at a constant di stance of 36 inc hes fr om the x-ray tube , a wedge-shape d bail was constructed. It was

dec ided that , although a clearer plate might be Ob tained by an obl ique s hot , the lat ral shot would be best in order t o minimize po sib le dis tortion of t he natural articulate angles or the b one of the thorac ic l imb . In t he resulting plate , it was easy to pick out the left limb b ones trom those of the r ight limb . In all c ses the left side was studied as this was the si de pressed

ga1nst t he pl te.

The princ iple us d in d i st inguishing b tween the two l imbs on the X-ray plate is i ll ustrated in Fi gur 9. As y

plate

X-ray tube -

- -

lja' A'

� - - -

- -_{- -}-

-

-

�ig. 9 . --Line diagram show�g principle used in i dentifyi�g l imb bonea of the right and left leg on the X-ray plate . In the diagram

•

A

•

and

•B•

are of the aaae length but their reapective iaagea o the X-ray plat

be readily seen tram Figure

9 ,

tne bone nearer the plate will be smaller and c lose� to the normal size.

The setting used on tne x-ray mac nine wa, : -

H9 2011A !seconds Distance-- 36 inc he s

The H value i s a c ontrol in the mac hine that , when altered

(assuming a c onstant MA (milliamperes) , will change the Kv. p

(Kilovolts-peak ) . The Kv. p (kilovolts-peak) in t he above settings is 70. 9.

With t he long exposure used it was inevitable that s ame

movement o f the animal would take place. It s o happened t hat six of the first twenty r di ographs had to be repeated bec aus of movement of the animal. The sl ightest mov other than t hat of the breatbing , will result in fuzziness and make

defini t i on difficult.

The setting to be used on t he mac hine was worked out by a meth od of tri 1 and error and , as was di scovered later in

further radiography , could be improved upon by decreasing tbe MA (mdlliamperes) and inc reasing the H value. However , the radio- graphs obtained were suff ic iently sati sfac t ory to define t he

points sought. Sinc e no literature on t he x-raying of s h p tran the lateral t horax view was available , the setting sugg steel by Kirk ( 1 937 ) in radi ograph.ing a Great Dane dog was used as

starting point.

To t t he plat s , use was made ot a dark room .safe-li gbt from which the amber glass sheet had been removed.

Under this amber glass was a plate of opal glass. On tbis the x-ray plates re placed and a sheet ot arc hit eta ' trac ing

papar was J.aid on top in r to trace outl ines of th 1 needed to measure tbe vari ous angles c onsi dered.

-45-

P. Formal Saline Fixati on.

1 .

Method ,2!: fixati on.

The ewe s were f i rst narc otized with an intravenous

in 3ection of Thicentone Sodi um. After l osing c onsc i ousness

they were placed on a squared b oard agai nst which t h ey had been previ ously photographed.

T hey were banked into posi ti on b y means of small parti ally filled sand b ags.

(

Shown in Fi gure 10. ) The

ob server di rec t ing the pos i t i oning was in a vert ic al pos i t i on over t he sbeep. T he live animal photographs we re 1n his

possess ion and t be placement of t he animals ' body and l imb s were orien te d f'ran the posi t i ons shown in the phot ographs. The ob server-sheep dis tanc e was s ixteen feet which was the c amera­ sub jec t di stanc e during the previ ous phot ographing of the �� When the sheep ' s pos i t i on , as shown by t he photograph , was

attaine d , an inc i s i on was made ab out halt way up the nec k on t he left s i de just below the vent ral edge o f the brachi ocephal icus. T he j ugular vein was then se7ered in order to insert a c annula

through lftli c h the t ixing s olution fl owed. The fixing s oluti on was f ormal saline which c ontained 100 cc . of forma1 1n and 8. 5

gms. s odium chloride per l i tre of soluti on. The container ot

s oluti on was about seven feet ab ove the a nimal. As the f s al ine flowed in to one end of the vein , t he c ontents of t be bl ood stream flowed out the othe r. When the liquid flowing

out became clear {being almos t pure f ormal saline s olut i on ) , the tree e nd ot the ve in was tied and ab ou t two additi onal li tres ot

the s olution all owed to tlow in. This �s all the c adaver

would take b tore pressure was bui l t up to atop the tl ow. Twelve to fourteen litres ot the s oluti on were used on each

animal . In a s imilar anatomical atucST St. Iwanoff

(

1939 ) used

7-8 li tree ot 8 per cent olut i on.

In order t o ensure that the c ontents of t be rumen r well saturated with the f ixing solution , an addi tional amount ot 50 cc . was 1n3ec te d through tile stomach walls. Thi s was to prevent poaatble fermentati on.and Ub sequent tor.mation at gas a whicll migbt bave the ef'fec t ot distorting t he ciuiaTer. The

animals subjec\ed to the f ixing treatment re weighed prior to and after fixing. On the day following fixing the b odies were

again photogr phed against the squared background from rt�c&l di stanc e of s�iteen feet.

\

On the day after the

�

ixing proce ss , t he six cad$vers

\

were measured in the same manner as when they were alive. T�e measurements taken were : - heart girth , he ight at wi thers ,

of thorax and wi dth between . the tuberosities of the humeri .

replic tions of eac h me surement were made on each cadaver. In addi tion shoulder mould s previ ously desc ribed was taken.

2.

.2! lli

fixed an imal s.

The formal sal ine f ixed cadavers were placed in a posi�n

closely approximating their stanc e Wben x-rayed alive . This

was done using the same equipment set at t he identical posit ions used in t he l ive an�l radi ography. These pos it i ons had been marked while t he x-raying of the live animals had been in pro- gress. In order to find more suitabl e setting for penetra�

the thorac ic region , several more test settings were attempted us ing the pr vious settin g as guide. In the same setting

tba t was used for the live animals , there appeared to be no ditferenc re ult ing from the 1 l ine impregnation or the b ody tissu s. In a s tting of 25 IIA ( milliamperes ) nd Kv. p

( kilovolts-peak) of 72, the radi ograph lacked c ontrast. Bow- ever , when the IIA ( milliamperes) were l owered t o 1 5 and the Kv. p ( kilovolts-p

ak)

increased to 83 , the d f inition was greatly improved. The new s tting used was : -

B1 1 1 511A. !sec onds Distance 36 inc bea

3. Dissection i!£, � fixed

The dissection was muscle by muscle of all mu cle ot the 1 ft shouider girdle , the muscles of the left shoulder and the � muscles of the left tore limb . The left forearm mus

re treat d a. group.

After the in of the s boulder and arm gi on bad b n re oved,the anterior portion of the panniculu carno us was

-47-

reflec te� Thi s muscle did not enter the stuQ1. However , the t t me dial to i t wh ic b was lateral to musc les t hat were removed was wei ghed. The f'at lateral to and between all

muscles dis sec ted was remov d and we igh�d. The f t b etween or l ateral to the thorac ic wall but medi al to the deepest musc le

di ssec ted out was not removed. Muscle , tendon and periosteum

removed whilst cleaning b ones and musc les was we i ghed wit h the f'at.

The same . order was mainta ined throughout the dissecti on on 1 1 an�l s , and prec auti ons were taken against any evapo-

rati on that might occ ur during the d i s sec ti on per iod. Tbe

weather at the t ime was c ool and damp and there was l i ttle air movement in the dissecting r ooms , b oth fac tors which helped keep p o sible evaporat i on losses to a minimUD4 T he di s s ec t i on work

was done by t he same person tb.roug h ou t and eac h animal required

b e tween 1 2 to 14 hours di s sec t i on time . The musc les were

l if ted out , c leaned of fat and tendon , we i ghed , me s ure d , c ross­ sec t ions taken and vol ume obtained by immersion.

A l i s t of' the musc le s di ssec ted f'oll ows : -

Trapez i us Supraspinatus

Rhomboideus Infraspinatu

Lati s simus dors i Tere s mdnor

Brac h i oc pbal ic us Sub sc pular i s

Omo-transversarous Teres maj or

Superfic ial pec toral C or c o-brac hial i s

Deep pec tor 1 Biceps brac hi i

Sterno-sc pularus Brac h1al 1 s

Serratus t horac is Tensor f' sc i antibrac �

De l to i d pars acr omi l i s Tric p s brae h i i De l t o i d rs scapulari s Anc oneus

'l'b.e muscl e s of t he f' o re rm were treate d as one group in t he we ighing.

The b one s tha t were di ss ec ted out and me sure d were : ­ the se ptlla , t he hwne rus , the radi us-ulna , the metac arp 1 and the

thor c ie rtebrae. .•

Pos it ions of the abo ve and b ones are llown in Fi gures 1 1 , 12, 1 3 , whioh illus trat diff r nt tages in t he dis sec tion proc dure .

Fig . 10 . --Showing the animal banked int o po sition w i th part i ally filled sand bags in pre parati on f or f ixing wi th f ormal saline s olution .

Fig . 11 . --Lateral mus cle s of the s houlder after

the panniculus c arno s us mus cle has b e e n refle c te d � a , Trape zius ; b , brachi o c e phalicus ; c , omo ­ transvers arius ; d , infras pinatus ; e , lat is s imus d ors i ; f , tric e ps brac hii ; g , t ens or fas ciae antibrachii ; h , delt oideus pars s capularis .

-4�-

Fig . 12 . --Anatomy of the s houlder re gion af t e r the removal of s ome of the lat e ral mus c l e s .

a , Latis s imus dors i ; b , de e p pe c t o ral ; c , b i c e ps brac hi i ; d , supras pinatus ; e , s e rratus t horacis ;

f , t e re s minor ; g , s c apula ; h , cartilage of t he s c apula .

F i g . 13 . --ve ntro-lat e ral view of mus c l e s of t he pe c t oral limb .

a , Brac hi o c e pha l i c us ; b , superf i c ial pe ct oral ; c , de e p pe c toral ; s t e rn o -s c apulatis .

this outline was measured tor area with t he planimeter.

The l i gamentum nuc hae was measured tor length b oth

�

..!..!E!

and when di s sected out of the animal. we igned and measured tor depth and width.

It was al s o

Ac tual ly , not the entire li gamentum nuc hea was treate d , but only the tunnic ular part of t � l i gament anteri or to the c ut made at the j unc t i on between t he thorac ic and lumbar vertebrae.

of the tunnicular portion.

4. Treatment

.2! 1!.!! .m.u.s.c.l.e.-s

This inc lude d most

After eac h musc le had been cleaned of fat and tendon it was weighed to the nearest 0. 1 gm. and t hen oriented on a sheet of paper in the approx imat e position i t had occupied in t he

animal. The greatest widt h, the greatest length and t he

greatest depth were determdned using a pair of dividers. After being spread to t he proper dimensi on t he dividers were placed on

a steel rule and t he r eading was made t o the nearest _o. 1 cm.

While the muscles were still on the s beet ot paper a penc il out­ line ot each · one was drawn tor future measurement or area.

After this trac ing the muscles were severe d and an outl ine dl'>awn

of t heir cross-sections.

Followin g the ab ove treatmen t , the volume of eac h muscle

was dete�ined by immersion. The water in the apparatus used drained from an overfiow and the surface tension was afterwards

decreased by adding three drops ot Teepol. Then the muscle was

immersed and t he overflow c ollected in a vessel of known wei ght. When the overtlow had stopped the surface tension was again

decreas d w1 th three mor drops ot Teepol. The total ov rtlow

caused by the musc le was weighed to the nearest 0. 1

�

Later a planimeter was used t o determine the area within

the traced outline of eac h muscle. This me�hod ot meas ur ing area i s qui-te acc urate according t o Burns and Clarkaon.

(

1 949 ) lltlo t ound that there was no error in tne aaurementa of' areas except

-51 -

in the c ases of areas of leas than 50 sq. ...._ in whic h case the

maximum error was three per cent and t he average error o. 5 per

cent.

In order to determi ne the a cc uraey of the planimeter used, tests were made on areas of known size. Two areas were

In document Tecnología & Sociedad, Nº 5, 2016 (número completo) (página 43-45)