Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author. THE MORPHOLOGY AND MORPHOMETRICS OF LYMPH NODES OF SHEEP AND LAr1BS: A STUDY OF NORMAL SHEEP AND THOSE WITH ARTHRITIS A THESIS PRESENTED IN PARTIAL ( 20%) FULFILMENT OF THE DEGREE OF MASTER OF PHILOSOPHY IN VETERINARY PATHOLOGY AND PUBLIC HEALTH AT MASSEY UNIVERSITY, NEW ZEALAND SHUTANG,YAO 1986 1 SUMMARY N i neteen g roups of l ymph nodes from s i x Romney ewe s and s i x fema l e l ambs aged seven yea r s and s i x months re spect i ve l y a s we l l a s 50 pop l i teal l ymph node s from furt her 2 5 l ambs we re exami ned . The s i ze , we i ght and s hape of e a c h node wa s measured a nd recorded . We ight wa s found to be the mo st objecti ve i nd i rect method of descr ibi ng the s i z e of a l ymph node . There wa s a wi de range of norma l we ights , both between l eft and ri ght l ymph node s from the same a n ima l and between the same node from d i fferent a n i ma l s . I n retrospect , more a n ima l s s houl d have been exami ned to determi ne t he extent of these ra nge s . The re l at i ve total we i ght of l ymph nodes i n re l at i on to c a rca se we i g ht wa s greater i n l ambs t han i n ewes , and t he jejuna l l ymph node s s howed the g reatest d i fference . The dry matter content of l ymph nodes from l ambs wa s greater than that from ewe s . Twen ty- s i x st i fl e and hoc k jo i n t s , wh i c h had been c l a s s i fi ed a s a rthri t i c by meat i n s pectors , together wi th t he a s soci ated i ps i l atera l and contra l atera l popl i te a l a n d med i a l i l i ac l ymph nodes were exami ned . On l y 6 2% of condemned jo i nts h ad s i gns of macroscop i c pathol og i ca l c hange . On l y s i x popl i teal nodes and one med i a l i l i ac node were e n l a rged . There wa s no corre l a t i on between en l a rgement of t hese nodes and s i gn s of d i sease i n t hese s t i fl e or hock joi nts . E v i dence i s pre sented to s how t hat pathol ogi ca l en l a rgement of l ymph nodes may often be i nd i st i ngu i s habl e , o n v i sua l exami n at i on , from norma l l ymph nodes a t the upper l i mi ts of t he normal ra nge . The se fi nd i ngs have re l evance to a c ri t i ca l eva l uat i on of trad i t i on a l meat i n specti on procedure s . ACKNOWLEDGEMENTS I wi s h to t han k t he Faculty of Veteri nary Sci ence at Ma s sey Un i vers i ty for prov i d i ng me wi t h the opportun i ty to s tudy for t he degree of Ma ster of P h ilosophy . I wi s h to expre s s my mo st s i ncere grati tude to my ch i ef s upervi s or , Professor D . K . Blac kmore who s o generously gave of hi s valuable t i me a n d a s s i sted a n d s upported me t hroughout t he con structi on of t h i s t he s i s . I am mo st grateful to Or A . S . Da v i e s , my supervi sor , for h i s much apprec i ated adv i ce and a s s i stance rega rd i ng a n atomi cal matters , and h i s most valuable superv i s i on dur i ng the work of th i s t he s i s . I would also l i ke to express my s i ncere g rat i tude to Mr . P . Mad i e who made hi mself a v a ilable at all t i mes to prov i de a s s i s tance wi th h i s broad knowledge and exper i ence . My t h a n k s a re also extended to : Or M . R . Alley for provi d i ng me wi th experi mental a n i mals a nd h i s enthu s i a sm towa rd s my study; O r G . V . Petersen for 2 h i s con s truct i ve s ugge s t i ons; Dr . D . J . Hamp son for help i ng me to wo rk out some stati st i cal f i g ure s; Mrs A. Scott , t he sec retary of the Department for her k i ndne s s of teac h i ng me to operate t he computer; t he staff at Longburn Freez i ng Works for a s s i st i n g me wi t h the collecti ng of samples , a n d all of my fri ends who gave me a s s i stance i n one way or another duri ng t he prepara t i on of t h i s thes i s . I Fi n ally , I heartly thank my wi fe , X i u Q i n , for her encouragement and mental A s upport , a n d my paren t s , parents- i n -law , and all my relat i ve s for t he i r look i ng a fter my two lovely d a ug hters and encouragements duri ng my e ndeavours i n New Zealand . SUMMARY ACKNOWLEDGEMENTS GENERAL I NTRODUCT I ON MATERIALS AND METHODS CONTENTS SECTI ON-ONE t10RPHOLOGY AND MORPHOMETRieS OF LYMPH NODES NORMAL LAMBS AND EWES RESULTS D I SCUSSI ON FROM SECTI ON-TWO THE EFFECTS OF ARTHR I T I S ON THE S I ZE OF POP L I TEAL AND MED I AL I L IAC LYMPH NODES RESULTS D I SCUSS I ON GENERAL D I SCUSSI ON RE FERENCES APPEND I X Page 1 2 7 1 3 17 17 83 89 89 92 94 96 100 3 Tabl e 1 2 3 4 5 6 7 8 LIST OF TABLES Age a n d l i ve a n d carcase we i g hts of l ambs exami ned Age a nd l i ve a n d carcase we i g hts of ewe s exami ned We i g ht of l ymph nodes of l ambs We i g ht of 50 popl i teal node s of 25 Romney l ambs We i g ht of l ymph nodes of ewe s Average mea s urement of l ymph node s of l ambs Ave rage mea s urement of l ymph nodes of ewe s Tota l we i g ht of l ymph node s of l ambs and percentage of body and c a rc a se we i g ht 9 Tota l we i g ht of l ymph nodes of ewe s and percentage of body and ca rcase we i g ht 10 Wet a n d dry we i g hts of l ymph nodes of l ambs 1 1 Wet a n d dry we i g hts of l ymph nodes of ewes 1 2 The max i ma l d i fferences o f we i ghts ( g ) of l ymph nodes from s i x l ambs and s i x ewes : A compa ri son of i ntra and i n te r a n imal d i fference s . Page 1 7 18 70 7 1 7 2 7 5 7 6 7 8 7 9 8 0 8 1 8 2 4 LIST OF FIGURES Figure Page 1 Shape of man dibul ar nodes of l ambs and ewe s 20 2 Shape of pa rotid node s of l ambs and ewe s 22 3 Shape of l atera l retropha ryngea l nodes of l ambs and ewe s 24 4 Shape of medial retropha ryngea l nodes of l ambs and ewe s 26 5 Shape of superficia l cervica l nodes of l ambs and ewe s 28 6 S hape of proper axil l a ry nod e s of l amb s and ewe s 7 S hape of pop l itea l nodes of l ambs and ewe s 30 32 8 S hape of ischiatic nodes of l ambs and ewe s 34 9 Shape of s ubi l iac nodes of l ambs and ewe s 36 10 Shape of media l il iac nodes o f l ambs a nd ewe s 39 11 Shape of rena l nodes of l ambs and ewe s 41 12 Shape of superficia l inguinal nodes of l ambs and ewe s 43 13 Shape of l eft t ra cheobronchia l nodes of l ambs and ewe s 45 14 Shape of cra nia l tracheobronchia l nodes of l ambs and ewes 47 15 Shape of cauda l media stina l n odes of l ambs 49 16 Shape of cauda l media stinal nodes of ewe s 17 Shape o f hepatic nodes of l ambs and ewe s 18 Shape of co l ic n odes of l ambs a nd ewe s 19 Shape o f i l eoco l ic nodes of l ambs and ewes 20 Shape of jejuna l nodes of l amb 1 21 Shape of j e juna l node s of l amb 2 22 Shape of je juna l nodes of l amb 3 23 Shape of jej u n a l nodes of l amb 4 50 52 54 56 58 59 60 61 5 6 24 S h a pe of jejuna l nodes of 1 amb 5 62 25 S h a pe of jej una l nodes of l amb 6 63 26 S h a pe of jej una l nodes of ewe 1 64 27 Shape of jej una l nodes of ewe 2 65 28 Shape of jej un a l nodes of ewe 3 66 29 Shape of jej una l nodes of ewe 4 67 30 Shape of jej un a l nodes of ewe 5 68 31 Shape of jejuna l nodes of ewe 6 69 32 Di s t ribution of weight of popl itea 1 l ymph nodes 73 33 Hypothetica l distribution of weight of norma 1 and a bnorma 1 pop l itea l l ymph nodes 74 GENERAL INTRODUCTION Durinq t he history of man , the mo st serious meat borne diseases were proba b l y t ri chinel l o sis and tuberc u l osis . Owen wa s the first person to recognize Trichinel l a spira l l i s (Hoeden , 1964) and Koch the first to isol ate Mycobacterium tubercu l osis (Ma rtin , 1978) in 1835 and 1882 respectivel y . These disea ses had been a major cause of h uman morbidity and morta l ity for many centuries before the infectiou s aqents were described . I t i s interesting to 7 note that l e sions of tubercu l o sis were found in mummies of t he Rameses dynasties which a re some 30 centuries ol d a nd human trichinel l osis o c c urred in ea rl y it epochs of Eu ropean civil ization wit hout being rea lised . A With the devel opment of modern concept s of disea se , g reater attention wa s paid to the source and hand ling of meat for human con sumption (Brand l y , Miga ki and Tayl o r , 1966). Since meat is a n es sentia l source of h uman food , a knowl edge and understanding of potential meat borne disea ses is nece s sary . I t has become ac cepted t h a t meat in s pection is a n indispen sab l e branch of meat hygiene in rel a tion to t he control of mea t borne disea ses . Meat in s pection inc l udes two main a spect s ; ante mortem inspection and post mortem inspection . Post mortem in spection has u sua l l y been rega rded a s the mo st important sin g l e step in the who l e of meat inspection proced ures (Petersen , 1979). The major aim of post mortem inspection is to det ain any carcase , or part of it , which i s not fit for h uman consumption . Therefore , post mortem inspection remains an es sentia l a nd major part of meat in s pection procedures . Pre sent meat i ns pect i on proced u res date bac k approxi mate l y one hund red s years a n d a re based o n the d i agnos i s of the mos t preva l ent zoonot i c d i seaes of A centra l E u rope i n the l ate n i neteenth centuri e s wh i c h were t uberc u l o s i s and tr i c h i n e l l o s i s ( Bl a c kmore , 1983 ) . The a ppea rance of l ymph nodes h a s been con s i dered to be usefu l g u i de s to the pre s ence of d i sea se and a l so to i nd i cate the extent of d i sease ( Dyett , Huches a n d Jones , 1 98 1 ) . The exami n at i on of l ymph nodes v i s ua l l y , by pa l pat i on a n d by i nc i s i on , h a s been a fundamenta l component of meat i n s pect i on s i nce the i ntroduc t i on of rout i ne i n spect ion p rocedure s i n the mi d 19th century 8 ( Skovga ard , 1 98 1 ) . I n some condi t i on s , changes i n the s tructure of l ymph nodes , a pa rt from be i ng a u sefu l i nd i cat i on of the a rea affected , may i nd i cate the type of d i sea se p roces s . For i n stance , i n many c a se s of chron i c bov i ne tubercu l o s i s the l ymph nodes dra i n i n g a n i n fected area a re both en l a rged and s how typ i ca l granu l omatous changes i nc l ud i ng c a seat ion and c a l c i fi cat i on ( Mon l u x and Mon l ux , 197 2 ) . I n c a se s of a c ute enteri t i s t he me senter i c l ymph nodes can be swol l en and oedematous and s how obvi ous i nfl ammatory c hanges . I n the more c h ron i c d i seases wh i c h re s u l t i n second ary c hange i n the l ymph nodes , e n l a rgement may be the on l y o bv io u s g ro s s s i gn of a bnorma l i ty . For i n s tance , l on g stand i ng c a ses of act i nobac i l l os i s often re s u l t i n g ro s s en l argement o f t h e ret ropharyngea l a n d mand i bu l a r l ymph node s ( Thornton and Gracey , 1 9 7 4 ) . By i nc i s i ng a ffected l ymph node s , a meat i n spector dete rmi ne s whether or not the c a rc a se or part of i t can be passed a s norma l and f i t for human consumpt i on or shoul d be deta i ned due to patho l og i c a l changes ref l ected i n i ts l ymph node s . Thus a knowl edge of the norma l appearance , l oc a t i on , a rea of d ra i nage a n d funct i on of l ymph node s i s of fundamenta l i mpo rtance i n the meat i n s pect i on (Wi l son , 1980). 9 The l ymphat i c sys tem has genera l l y been regarded a s con s i st i n g of two ma i n e l ements; (1), a n exten s i ve netwo r k of ve s se l s conta i n i n g l ymph , i n wh i c h a re found the many prote i n s of p l a sma a s we l l a s l a rge n umber of cel l s , the majori ty of wh i ch a re l ymphocytes , and (2), s cattered ma s se s of l ymphoi d t i s s ue , often i n the form o f d i screte l ymph node s , w i th wh i c h these ve s se l s c ommun i cate (Yoffey and Cou rt i ce , 1970). The l ymphat i c ve s se l s const i tute one way c hanne l s wh i c h run a l mo s t i n para l l e l to the veno u s system and eventua l l y empty i nto the c ran i a l ven a cava o r i ts branches ( Frandson , 1972). The l ymphat i c ves se l s begi n a s a network of very fi ne l ymph c a p i l l a ri e s wi th b l i nd e xtremi t i e s. These cap i l l a r i e s g radua l l y en l a rge i nto th i n wa l l ed l ymphat i c ve s sel s whi ch d i sc ha rge the l ymph i nto the l ymph n odes. The l ymphat i c vesse l s ea rr i ng l ymph i nto l ymph nodes a re known a s afferent l ympha t i c s . The l ymphat i c ve s sel s conveyi ng l ymph away from l ymph node s a re termed efferent l ympha t i c s . Lymph n odes a re d i s crete nodu l e s of l ymphoi d t i s s ue , whose l ocat i on i s u s ua l l y a n atomi ca l l y constant , found a l ong the course of l ymphat i c vesse l s (Mi a l e a n d Rywl i n , 1977). A l ymph n ode i s d i v i ded i nto two parts , t he outer part or c orte x , and a n i nner part or medu l l a . The cortex conta i ns l ymphat i c nodu l e s i n wh i ch there a re germi n a l centers ( somet i me s referred to a s secondary nodu l es ) . A network o f ret i cu l a r f i bers from the pyrami d a l a reas cont i nue i nto the medu l l a where the narrow ends of the pyrami d a l a reas merge i nto structure s 10 c a l l ed med u l l a ry cords ( Ham and Cormack, 1979). An a re a d ra i ned by a l ymph node by afferent ve s sel s i s termed a d ra i nage a rea . When l ymph pa s se s through the nodes, fore i gn substances such a s bacteri a and other p art i c u l ate matter wi l l often be deta i ned by pha gocyt i c act i v i ty . Effe rent l ymphat i c s may dra i n to o n e o r more other l ymph nodes before they reach the bl ood s tream . � Hema l l ymph node s a re a l so pre sent i n catt l e and shee p . They a re sma l l A dark red o r bl a c k st ructures, the co l our depen d i ng on the amount of bl ood or b l ood p i gment present . They resembl e l ymph nodes but a re i n terposed on the cou rse of sma l l b l ood ve s sel s ( Fra n dson, 1972). � Hema l l ymph node s vary between A 1 to 20 mm i n s i ze a n d i n sma l l rum i nants they rare l y exceed 5 mm . I n cattl e they a re s e l dom more than 10 mm . The exact n umbe r present i s un known but i t has been e s t i ma ted that i n s heep there a re between 30 and 300 ( Vol l me rha us, 1981). Each node con s i sts of a n outer caps u l e, trabec u l ae and cave rnous b l ood spaces and l ympho i d t i s s ue, s i mi l ar to the structure of the spl een and hav i n g no l ymph ducts or l ymphat i c s pace s . These n odes a re found ma i n ly i n the ba c k fat and a l ong the a orta, but many occur e l s ewhere in the body . � Hema l l ymph node s a re ent i re l y a bsent i n humans, horse s and p i g s, but a few � are found i n dogs ( Macgregor, 1980). They have a we l l deve l oped peri phera l s i n u s wh i c h conta i n s b l ood, from wh i c h seconda ry s i n u ses e xtend i n to the i nteri o r, a n d form an i n tercommun i cat i ng system of b l ood s p a ce s . There i s no c l ear d i v i s i on i nto cort i ca l and medu l l a ry substance, and the t ra bec u l ae conta i n smooth mus c l e ce l l s . A l t hough they resembl e the spl een i n s ome res pects, the i r s i gn i fi ca n ce i s not yet c l ear ( Si s son and Gros sman, 1959). They a re not 11 con s i dered i mportant i n terms of meat i n s pec t i on . The fun c t i on of l ymph nodes i n c l udes the format i on of l ymphocytes and the produc t i on o f ant i bod i es , a s we l l as the fi tra t i on of l ymph (Wi a l e and Rywl i n , 1977). I f t he nodes recei ve afferent ves se l s from a n area of the body wh i c h i s i n fected , secondary i n fecti on and i n fl ammatory c hange of t he nodes may occur . Thus an i n fl ammatory reacti on i n a l ymph node may i ndi cate a con current i n fl ammatory react ion i n i ts area of dra i nage . These react i ve proce s se s i n l ymph nodes a re genera l l y grouped together under the term a c ute o r c hron i c l ymphade n i t i s (N i e berl e and Cohrs , 1967). I n a c ute l ymphaden i t i s , the node i s soft , mo i s t and hype raem i c . The node bu lge s a bove the cut s u rface and may conta i n a rea s of necro s i s . I n c hron i c l ymphaden i t i s , hype raemi a i s l e s s a l though t h e nodes may rema i n oedematous . The affected nodes a re i n i t i a l l y en l arged a nd fi rm but may l ater become sma l l e r and i ndurated (J ubb and Kennedy , 1963). Changes i n the s i z e , col our and con s i stency of the l ymph nodes are con s i dered to be i nd i c a t i ve of acute septi caemi c or pyaemi c cond i t i ons (Thornton , 1970). The re s ponse of a l ymph node to an i rri tant i s norma l l y rap i d, wi th en l a rgement a nd conge st i on of i ts s u bstance and pos s i b l y degenera t i ve changes a l so . Thus t he s i ze , co l our and cons i s tency of l ymph node s a re con s i dered va l uabl e i n the e s t i ma t i on of d i sea se proces se s in the a n i ma l body duri ng i n spec t i on p rocedure s (Thornton a n d Gracey, 1974). I n many cases of rout i ne meat i n s pec t i on , l ymph nodes a re o n l y i nc i sed when they a re en l a rged a s j udged by pa l pa t i o n or a ppea rance . Thu s a knowl edge of the s i z e of norma l l ymph nodes i s essent i a l before an en l arged n ode can be recogn i zed . 12 Standard texts o n veteri n a ry a n atomy descr i be the l oc a t i on a n d a rea of dra i nage of the l ymph nodes of the body. Howeve r , there i s a l ac k of i n format i on on the s i ze , and to a l e sser extent , the shape of the l ymph nodes i n d i fferent spec i es. There i s a l so l i tt l e i n format i on i n these standa rd texts regard i ng c hanges i n s i ze of l ymph nodes wi th a ge. Yet i t has been shown that the l ymphat i c t i s sue of huma n s decreases i n amount (i nvo l ut i on ) wi th age (We i s s and Greep , 1977). I n New Zea l and more than 30 mi l l i on s heep a re s l aughtered each yea r , and s ubjected to rout i ne post mortem i n s pecti on. These procedures i n vol ve the pa l pa t i on of l ymph nodes and i n c erta i n c a ses i nc i s i on a l so. I n s p i te of t h i s , i n format i on on the q uant i tat i ve morphol ogy of l ymph nodes from s heep i s l ac k i ng. I t therefo re become apparent that before i t cou l d be determi ned whether or not l ymph node en l argement was a useful i n d i c a t i on of d i sea ses of re l e vence to i n spec t i on procedure s , norma l an i ma l s wou l d have to be stud i ed. F i rst , i nforma t i on on the morphol ogy and morphometry of l ymph nodes from appare nt l y norma l s heep and l ambs was col l ected (Secti on 1 ) . Secon d l y , based on the re s u l t s of th i s i n i t i a l work , a study wa s conducted to determi ne any poss i b l e corre l a t i on between arthr i t i s i n s heep and the s i ze of the l ymph nodes dra i n i n g an affected area (Sect i on 2). 13 MATERIALS AND METHODS Examination of lymph nodes from nonnal animals S i x c l i n i ca l l y norma l , seven-year-o l d Romney ewes and s i x c l i n i ca l l y norma l , s i x-month-ol d Romney l ambs were s l aug htered and ev i s cerated . The l i ve and c arca se we i g ht of the a n ima l s we re recorded and the 19 major groups of l ymph nodes of c a rc a se and v i s cera were removed wi th i n three hours of s l a ug hter (see Append i x ) . F i fty popl i tea l l ymph nodes from a further 25 Romney l ambs , a pproximate l y 8 months of age , were removed from c a rcases of known we i ght , soon a fter they had been pa s sed a s fi t for human c on s umpt i on by i n s pectors a t a l oc a l works . Nodes were removed by careful d i s sect i on , v i s i b l e fat removed and the nodes CA.. we re p l aced i n a tray covered by d amp c l oth unt i l exami ned furthe r . " Description of location and area of drainage The l oc at i o n and area of dra i n age of l ymph nodes have been summari sed by Vol l me rhaus (1981) and Saar and Get ty (1975). These descri p t i ons a re provi ded i n the re s u l t s . Newer f i nd i ngs of the cauda l medi asti n a l n ode by A l berti ne , et a l , (1982) and Landol t , e t a l (1981) a re a l so i nc l uded . No contra ry evi dence wa s found d u ri n g the course of t h i s wor k . No i nvest i ga ti ons o n the course of afferent a n d efferen t l ymphat i c s were underta ken . 14 Measurement of size and shape The siz e , s hape and weight of each node wa s recorded . Size and s hape we re mea sured by p l acing the nodes on a piece of paper wi th a g ri d of hori zonta l and vertic a l l ine s 1 mm apart , and tra cing round the outl i ne . First , a n outl ine of the node wa s made wi th i ts two l onger a xes of l ength and wi d t h p a ra l l e l to t he paper . Then the node wa s turned t h rough 90°C s o that the l a rgest a x i s of l ength and the sma l l e st of t h i c kness we re pa ra l l e l to the pape r , and a second tra c i ng made . Thus the th i rd d imens i on of t h i c kness cou l d be mea su red . Nodes cou l d be divi ded accord i n g to s hape i nto two type s : t hose wh i c h were con stant l y k i dney or ova l i n s hape , were c l a s sed a s regu l a r . I n these nodes , the l e ngth , w i dth and t h i c kness were measured at their gre a test va l ues . I n the other i rregu l a r s haped nodes , mea surements of wi dth were e xp ressed a s means of the greate st and sma l l e st val ues obta i ned from t he fi rst trace . Measurement of weight A l l ind i v i dua l nodes were we i g hed a s soon a s the shape and s i ze had been recorded . I n certa i n c a ses such a s the jejuna l nodes , which occur e i ther a s a continuous node or a s eries of node s , the combi ned weight of a l l parts wa s recorded a s one . For s i x d i fferent g roups of nodes from 3 l ambs and 3 ewes (Tabl es 10 and 1 1 ) , t he d ry weight wa s recorded . These nodes were tra n s fe red to prewe i g hed g l a s s dishes and l eft in an oven at 1 10° C initia l l y for 29 hours . Dry weights were recorded after 1 7 and 29 hours re specti ve l y . A s t he re wa s no furt her 15 reduction in weight after 17 hours heating, only this period of drying was used in the majority of cases. Arthritis and associated diseases of the joint Nineteen stifle and seven hock joints from Romney lambs which had been judged as arthritic by meat inspectors were collected at a freezing works. Both the ipsilateral and where possible the contralateral popliteal and medial iliac lymph nodes from the legs were also examined. Both the joints and lymph nodes were transported in plastic bags to the laboratory. All the joints and lymph nodes were examined no more than three hours after they were taken from the works. Since the lymph nodes were put into the plastic bags still surrounded by fat, it was assumed that no significant loss of weight would have occurred before examination. The lymph nodes were examined first. After fat was trimmed off, the nodes were weighed and their size measured by the method described above. The joints and surrounding tissue, including tendon sheaths, were examined carefully to determine whether or not there was evidence of pathological change of the joint or surrounding tissues. The joints were divided into four categories; (a) normal; in which no gross pathological changes were observed. (b) Arthritis; as evidenced by intra-articular inflammatory changes of the capsule, abnormal changes on the surface of joint cartilage or an increase in the amount of synovial fluid. (c) Periarthritis; in which there were inflammatory changes of the periarticular tissue and evidence of periarticular fibrosis. 1 6 ( d ) Tendovag i n i tis ; i n whi ch there wa s ev i dence of i n fl ammatory change of the tendon sheaths wi th a n a s soc i ated exces s i ve amount of fl u i d wi thi n the sheaths . SECTION ONE MORPHOlOGY AND MORPHOMETRieS OF lYMPH NODES FROM NORMAl lAMBS AND EWES RESUlTS The l ambs a n d ewes exami ned were of norma l we i ght and confirmat i on for their age a n d sex. Tab l e s 1 and 2 g i ve deta i l s of the i r body and c a rcase we i g hts. Reference n umbe r of l amb L 1 L 2 L 3 L 4 L 5 L 6 Tabl e 1. Age , and l i ve and c a rc a se we i g hts of l ambs exami ned Age (month s ) 6 6 6 6 6 6 Li ve we i g ht (kg ) 31 28 30 27 27 27 Carcase we i g ht (kg ) 13. 8 13. 5 14. 0 12. 0 12. 4 11. 2 Percentage of c a rcase to l i ve we i g ht 45% 48% 47% 44% 46% 41% 17 Reference n umber of ewe E 1 E 2 E 3 E 4 E 5 E 6 Tabl e 2. Age , and l i ve and carca se we i ghts of ewes exami ned Age (yea rs ) 7 7 7 7 7 7 Li ve we i g h t ( kg ) 31. 9 33.9 34.5 34.0 42.0 31.7 Ca rca se we i gh t ( kg ) 11.2 13. 9 12.6 12.6 16. 4 15.6 Percentage of c a rc a se to l i ve we i g ht 35% 41% 37% 37% 39% 49% 18 A genera l descr i pti on of each of the node s exami ned together wi th d i a grams of the i r out l i ne s ( F i g ure s 1-31) i s pre sented i n the fo l l owi ng pages of th i s sect i on. Tab l e s 3, 4 and 5 at the end of th i s account g i ve detai l s of the we i g ht of each node exami ned , and Tabl e s 6 and 7 s how the average mea s urement of each of the l ymph nodes of l ambs and ewes. Tabl e s 8 and 9 g i ve the tota l we i g ht of l ymph nodes of each of the l ambs and ewe s a nd a s percentages of t he i r body and carcase we i g hts. The fol l owi ng descri pt i o n of each node i s d i v i ded i nto fi ve parts; l ocati o n , a rea of d ra i nage , efferent route s , n umbe r , and s hape and s i ze. A s ment i oned prev i ous l y , t h e i n formati on on n umbe r , and s h ape and s i ze wa s obta i ned by the a u thor. MANDIBULAR Locat i on The mand i bul a r node s l i e at the l evel of, or immedi a te l y cauda l to, the vascu l a r notch of the mandi bl e, cove red by cutaneous mus c l e. Area of dra i nage 19 Ventra l port i ons of the head i nc l ud i n g the s k i n of the l ower jaw, nose and l i p s, the o ra l cav i ty i nc l udi ng the tong ue, t he gum of the l ower j aw, part of the mu s c l e of ma st i c a t i on and the tong ue, and the mand i bu l a r s a l i vary g l and. Efferent routes The nodes dra i n to e i ther the l a tera l or the med i a l retropharyngea l nodes. Number I n a l l of the l ambs and four of the ewe s one node wa s found on each s i de. I n two o f the ewe s there were two nodes on the ri ght s i de and one on the l eft. Sh ape and S i ze ( see F i g ure 1 ) The nodes were i rregu l ar ki dney to oval i n shape, somewhat fl a ttened and of var i ab l e s i z e. I n l ambs, they ranged from 13-22 mm i n l en gth, 6-12 mm i n wi dth and 4-7 mm i n th i c kne s s and from 0. 23-1. 19 g i n we i g ht wi th a mean of 0.65 g. I n ewe s, they ranged from 10-29 mm i n l en gt h, 6-11 mm i n wi dth and 4-7 mm i n th i c kn e s s and from 0.23-1.12 g i n we i ght wi t h a mean of 0. 69 g. 1. 2. 3. 4. 5. 6. Left F i g ure 1 SHAPE OF MAND I BULAR NODES LAMBS EWES R i ght Left 20 R i ght 0 0 OD 0 0 00 0 0 0 oo 0 c:::> c ) 0 0 0 50 mm These and subsequent out l i ne s ( F i gures 1 - 3 1 ) are drawn at actua l s i ze . PAROTID Locat i on The pa rot i d nodes a re s i tuated ventra l to the temporo-mand i bu l a r jo i n t at the cauda l border of the ma s seter musc l e , compl ete l y covered by the pa rot i d s a l i va ry g l and. Area of dra i nage 2 1 T h e s k i n o f the upper ha l f of the head , i nc l ud i ng nostr i l s , mouth a n d n a s a l cavi ty , tongue , gums , musc l e s of ma sti c at ion , l i ps , eye l i ds , the pa rot i d s a l i va ry g l and , the ro stra l ha l f o f the l ower jaw and the extern a l e ar. Efferent routes The l atera l ret ropharyngeal n odes. Number One node wa s found on each s i de i n a l l the a n ima l s exami ned . Shape and S i ze (see F i gure 2 ) The nodes were o f dumbbe l l o r ki dney i n s hape , and somet imes e l ongated and of vari ab l e s i ze. I n l ambs , th�y ranged from 14-35 mm i n l ength , 7 - 1 5 mm i n wi dth and 4-7 mm i n t h i c kn e s s and from 0 . 6 3- 1 . 96 g i n we i g ht wi th a mean of 1 . 30 g . I n ewes , the nodes vari ed from 1 9 -36 mm in l ength , 7 - 14 mm in wi dth and 4-8 mm i n th i c knes s and from 0 . 60- 1 . 29 g i n we i g ht wi t h a mean of 1 . 02 g . 22 Figure 2 : SHAPE OF PAROT I D NODES LAMBS Left Right 1 . 00 2. 3. 0 4. 5 . CJO 6. DW EWES Left Right oo LATERAL RETROPHARYNGEAL Locati o n 23 The l atera l ret ropharyngeal nodes l i e ventral to the wi ng of the a t l a s on the l eft border of the parot i d s a l i vary g l and , covered by the a poneuros i s of the c l e i do-occ i p i ta l i s mu s c l e . Area of dra i nage The s k i n of the paroti d reg i on and deeper parts of the n ucha l reg i on , c a uda l and deeper structures of the head , and pa rot i d and med i a l retropharyngea l nodes . Effere nt routes They form the l a tera l root of the j ugu l a r trun k , or un i te to form the trache a l t run k . Number I n n i ne of the twe l ve a n i ma l s e xami ned , one node wa s found on each s i de . One ewe had two nodes on the r i ght s i de and one on the l eft . Another had two nodes o n both s i des , and i n one ewe , no node s on e i ther s i de cou l d be demonst rated . Shape and S i z e (see F i g ure 3 ) They were of fl attened k i dney t o ova l i n shape a n d o f vari a bl e s i z e . I n l ambs , they ranged from 10- 20 mm i n l ength , 5- 10 mm i n wi dth and 4- 6 mm i n thi c kn e s s and from 0 . 2 5-0 . 86 g i n we i gh t wi th a mean of 0 . 43 g . I n ewe s , they range d from 7 - 23 mm i n l ength , 5- 14 mm i n wi dth and 2- 7 mm i n th i c kness and from 0 . 22- 1 . 17 g i n we i ght wi t h a mean of 0 . 46 g . 24 Figure 3 : SHAPE OF LATERAL R ETROPHARYNGEAL NODES LAMBS EWES Left Right Left Right 1 • 0 0 0 2 . [ ) 0 oo 3 . 0 Absent 4 . 0 5 . 0 �CJ 6 . Oo Oo MEDIAL RETROPHARYNGEAL Loca t ion The med i a l retropharyngea l nod e s are s i tuated just dors a l to the l aryngo pharyn x . The ri ght and l eft nodes a re a bout 5 mm apart. Area of dra i n age 2 5 Mouth and n a s a l c a v i ty i nc l ud i n g gums , ma st i catory mus c l e s , musc l e s o f the tongue , pha ryn x , l a rynx and soft p a l ate , the s ub l i ngua l and mand i bu l ar s a l i v ary g l ands and the mand i bu l a r l ymph node s. Efferent routes To the l atera l retropharyngea l n odes , and they may a l so be i n vol ved i n the format i on of the j ugu l ar l ymphat i c trun k. N umber One node wa s found on each s i de i n a l l of the an ima l s exami ned. Shape a nd S i ze (See F i g ure 4 ) They we re of somewhat fl attened , tri angu l ar to ova l i n shape and of vari a b l e s i ze. I n l ambs , they ranged from 25-33 mm i n l ength , 1 2-22 mm i n wi dth and 6- 1 4 mm i n thi c knes s a n d from 2 . 1 2- 4 . 18 g i n we i ght wi th a mean of 2 . 98 g . I n ewe s , they v a r i e d from 1 5- 29 mm i n l ength , 8- 1 6 mm i n wi dth and 4-7 mm i n th i c knes s and from 0 . 39�1 . 63 g i n we i ght wi th a mean of 1 . 09 g. 1 . 2 . 3. 4. 5 . 6 . Fig ure 4 SHAPE OF MED I AL RETROPHARYNGEAL NODES LAMBS Left Right Left 26 EWES Right QC) o_ D 0 00 SUPERFICIAL CERVICAL locat i on The s uperfi c i a l cervi ca l nodes are a t the cran i a l border of the supra sp i n a t u s mu s c l e , covered by the cerv i c a l part of the t rapez i u s , the omotransve rs ari us and the c l e i do-occ i p i ta l i s mu sc l e . Area of dra i nage The s k i n and mu s c u l ature of the nec k , c auda l part of the head , externa l e ars , and l a tera l wa l l of the thorax up to the tenth i ntercosta l space , the t hora c i c l i mb i nc l ud i ng a l l deep s tructure d i s ta l to the c a rpa l jo i nt and a c ce s sory s u perfi c i a l l ymph nodes Efferent routes 27 The l eft node dra i n s i nto the j ugul a r trun k . The ri g h t node dra i n s e i ther , to t h e venou s ang l e o r , may jo i n t h e ri ght tra c heal trun k and form t h e ri ght l ymphat i c duct . N umbe r One node wa s found on each s i de i n 1 1 an i ma l s . One l amb had two nodes on the r i g h t s i de and one on the l eft . Shape and S i ze (see F i g ure 5 ) They we re of i rregu l a r , oval t o k i dney i n s hape and o f vari ab l e s i ze . I n l ambs , they ra nged from 1 2- 3 5 mm i n l ength , 9- 20 mm i n wi dth and 5- 1 0 mm i n t h i c kne s s and from 1 . 67- 3 . 03 g i n we i g ht wi th a mean of 2 . 64 g . I n ewes , the n ode s vari ed from 30- 44 mm i n l ength , 1 2- 2 1 mm i n wi dth and 5-7 mm in t h i c kness and from 1 . 47 - 3 . 02 g i n we i g ht wi t h a mean of 2 . 20 g . 1 . 2 . 3 . 4 . 5. 6. Figure 5 SHAPE O F SUPERF I CIAL C ERVICAL NODES LAMBS Left Right Left 0 0 28 EWES R i ght PROPER AXILlARY Loca t i on The prope r a xi l l a ry nodes are on the med i a l s urface of the teres major musc l e , i n t he ang l e formed by the s ubscapu l a r artery and ve i n and by the thoracodorsa l artery a nd ve i n . Area o f dra i n age D i s ta l a n d proxi ma l l i mb i n c l ud i ng the c a rpus , the med i a l s u rface of the scapu l a , s k i n of the c a uda l part of the shou l de r , the ventra l and l a tera l part of the thorac i c area a n d most of the musc l e s of the shou l der , brach i um and a ntebrac h i um , the deep and superfi c i a l pectora l mu s c l e s and the cutaneous musc l e s of the s hou l der regi on , and from the c u b i tal and a c ce s sory a x i l l a ry l ymph node s . Efferent routes A xi l l a ry nodes of the fi rst ri b . N umber I n fou r l ambs and fi ve ewe s one node on each s i de wa s recorded. I n two 29 l ambs and one ewe one n ode wa s found on the ri g h t s i de and n o nodes on the l eft . Sha�e and S i z e (see Fi g u re 6 ) They were ova l i n s hape and of vari ab l e s i z e . I n 1 ambs , they ranged from 9- 17 mm in l ength , 6- 10 mm i n wi dth a n d 2-8 mm i n th i c knes s a n d from 0 . 1 3- 0 . 46 g i n we i ght wi th a mean of 0 . 24 g wh i l e i n ewe s t hey var ied from 4- 1 1 mm i n l ength , 3- 7 mm i n wi dth and 2- 4 mm i n th i c knes s and from 0 . 03- 0 . 20 g in we i ght wi th a mea n of 0 . 09 g . 1 . 2 . 3 . 4 . 5 . 6 . Figure 6 SHAP E O F PROPER AXILLARY NODES Left Absent 0 Absent 0 0 LAMBS E W ES R i ght Left 0 Absent 0 0 0 0 0 0 0 0 0 a 30 R i ght 0 0 0 0 () POPLITEAL Locat i on The popl i tea l nodes l i e in the pop l itea l fossa , 25 mm deep i n the space between the g l uteobi ceps and semitendinosus musc l es . Area of dra i nage Foot , crus , sk in and subcut is d ista l to the l ocati on of t he l ymph nodes . A l though afferent vesse l s from musc l es , tendons and joints d ista l to the popl iteal l ymph nodes have not been descri bed , i t i s assumed t hat t hey are present . Efferent routes Isch i at i c nodes , the pe l v i c c av ity and the sacral and med i a l i l i ac nodes . Number One node was found on each si de in fi ve l ambs and fi ve ewes . In one l amb two nodes were recorded on the r i g ht si de and one on the l eft , and in one ewe two nodes were found on t he l eft si de and one on the right . Sh ape and S i ze ( see F igure 7 ) They were i rreg u l ar , ova l in shape and of vari abl e si z e . 3 1 In the in i t i a l si x l ambs examined , the nodes ranged from 1 0 - 24 mm in l ength , 6- 1 5 mm i n wi dth and 3-6 mm i n t h i c kness and from 0 . 7 4- 2 . 04 g in we ight wi t h a mean of 1 . 06 g . I n t he further 2 5 l ambs examined the nodes ranged from 1 . 7 0- 5 . 45 g i n we ight w ith a mean of 3 . 0 3 g ( See Tab l e 4 ) . In ewes , t hey ranged from 8- 27 mm in l ength , 5- 1 5 mm in wi dth and 4- 10 mm in th i c kness and from 0 . 5 1- 1 . 56 g in we ig ht with a mean of 0 . 90 g . 32 Figure 7 : SHAPE OF POPLITEAL NODES LAMBS Left Right 1 • 0 0 2 . 0 o8 3 . 0 0 4 . c:) 0 s. 0 0 6 . C)O EWES Left Right 0 0 0 0 0 0 00 (JG 0 ISCHIATIC Loc at i on The i sc h i a t i c node s l i e aga inst the l atera l s u rface of the broad s ac rotubera l l i gament nea r i ts cauda l bo rder . Area of dra inage Ta i l , i s c h i a t i c and t h i g h reg i ons . In some cases , secondary afferent ve s se l s ar i se from the pop l i teal and t he inconstant tubera l node s . Efferent route s Sacra l or med i a l i l i a c nodes . Number 33 In a l l of the l ambs and fi ve ewe s one node wa s found on e a c h s i de . I n one ewe three node s were recorded on the l e ft s i de and one on the r i ght . Shape and Si ze ( see F i gure 8 ) They were i rregu l a r, ova l i n shape and of va ri a b l e s i ze . In l ambs, t hey ranged from 7-16 mm in l ength, 5-12 mm in wi dth and 3-6 mm i n th i c knes s and from 0.14-0.74 g in we i g ht wi th a mean of 0.42 g . In ewe s, the nodes ranged from 3-14 mm in l ength, 3-10 mm in wi dth and 2-5 mm in th i c knes s and from 0.13-0.42 g in we i g ht wi th a mean o f 0.24 g . Left 1 • 2 . 3 . 4 . 5. 0 6. Figure 8 : SHAPE OF ISCHIATIC NODES LAMBS Right 0 0 0 0 Left D 0 0 oo 0 D 0 34 EWES Right 0 0 0 0 D SUB ILIAC Locat i on The s ub i l i a c nodes l i e mi dway betwee n the tuber coxae and the pate l l a . Area of dra i n age The l atera l a nd c ran i a l part of the thigh , l ateral and ve ntra l a bdomi n a l wa l l , the s k i n a n d s u bc ut i s of the pel v i c reg i on . Efferent routes Latera l a n d med i a l i l i ac node s . Number 35 Three l ambs and four ewe s had one node on each s i de . One l amb had two nodes on both s i des and two l ambs had two node s on the r ight s i de and one on the l e ft . One ewe h a d two nodes on the l eft s i de and one on the ri ght and another had three node s o n the l e ft s i de and o ne on the r ight . Shape and S i ze ( see F igure 9) The nodes we re i rregu l a r , banana to ova l i n shape and of var i a b l e s i ze . I n l ambs , they ra nged from 11-35 mm i n l ength , 5-12 mm i n wi dth and 3-5 mm i n thi c kness a n d from 0.36-1.16 g i n we ight wi th a mean of 0.89 g . I n ewe s , they var ied from 8-36 mm i n l ength , 5-11 mm i n wi dth and 3-6 mm i n th i c kn e s s and from 0.69-1.23 g in we ight w ith a mean o f 0.90 g . 1 . 2. 3 . 4 . 5. 6. Figure 9 : SHAPE OF SUBILIAC NODES Left c:? c� CJ LAMBS Right Left 0 �0 0 36 EWES Right 37 MEDIAL ILIAC Locat i on The med i a l i l i ac nodes a re l ocated on the external i l i a c a rte ry . The mo st crani omedi a l of t he se l i es in the ang l e between the aorta and externa l i l i a c artery and the or i g i n of t he deep c i rcumf l ex i l i ac a rtery . Area o f dra inage The s k i n of t he foot , hoc k and crus , the hoc k and st i fl e j o ints , and testes and ep i d i dymi s or ovary . Afferent ve s se l s a l so come from t he s a c ra l , i s c h i a t i c , superf i c i a l i ng u i na l and s ubi l i ac l ymph node s and partly from t he popl i te a l , deep i ngu ina l , t u bera l , g l utea l , coxa l and l atera l i l i ac l ymph node s . Efferent routes The efferent vesse l s g i ve ri se to the l umbar trunk and some go to t he l umbar aort i c l ymph node s . N umber One l amb had two nodes on bot h s i de s and another had t hree on eac h s i de . In two l ambs , two nodes were recorded on the l eft s i de and t hree on the ri g h t . One l amb and one ewe had fi ve node s on t he l eft s i de and three on the ri g h t . One l amb had s i x node s on the l eft s i de and fi ve on the ri g ht . I n two ewe s , two nodes were pre sent on t he l eft s i de and one on the ri ght , and anot her had four node s on both s i de s . One ewe had t hree nodes on t he l eft s i de and one on the ri ght , and anot her had one node on the l eft s i de and four on t he ri ght . Shape and Size ( s e e Figure 10) The nodes we re irregu l a r , oval to kidney in s hape , e l ongated and of variab l e size . 38 I n l ambs , t hey ranged from 3-40 mm in l engt h , 3-13 mm in width and 2-10 mm in thic knes s and from 0.51-1.70 g in weight with a mean of 1. 17 g . In ewe s , the nodes ranged from 4-80 mm in l ength , 2-13 mm in width and 2-5 mm in thic knes s and from 0.36-1. 81 g in weight with a mean of 1. 24 g . 1 . 2 . 3 . 4 . 5 . 6 . 39 Figure 10 : SHAPE O F MED I AL I L I AC NODES LAMBS Left Right �6 0 o\Jo C>o c:::) C) a o c :) 0 � 0 a 0 [J EWES Left Right c ) � ' ()CJO RENAL Locat i on 40 The rena l node s are l oc a ted i mmedi a te l y cauda l to the rena l b l ood ve s se l s . Area of dra inage The afferent and efferent l ymphat i c s have not been descr i bed . Number Fou r l ambs and fou r ewes had one node on each s i de . I n one l amb , two nodes were recorded on the right s i de and one on the l e ft , and another had two node s on the l eft s i de and one on the righ t . In one ewe , three nodes were demonstrated on both s i des , and another had si x node s on the r ight s i de and no nodes we re recorded on the l e ft . Shape and Si ze ( see F igure 11) They were ova l in s hape and of vari a b l e s i z e . In l ambs , the node s ranged from 4-20 mm in l ength , 4-10 mm in wi dth and 3-7 mm in t h i c knes s and from 0.14-1.00 g i n we ight wi th a mean of 0.32 g . I n ewe s , they ranged from 3-12 mm in l ength , 2-6 mm in wi dth and 1-5 mm i n t h i c knes s and from 0.10-0.63 g in we ight wi th a mean of 0.20 g . 41 Figure 1 1 : SHA P E OF R ENAL NODES LAMBS EWES Left Right Left Right 00 Absent 000 1 . 00() 2 . DD 0 0 3 . 0 0 4. 0 0 D 5 . 0 0 D D 6. 0 0 SUPERFICIAl INGUINAl Location The s u perficia l inguinal node s l ie c l ose to the externa l pudenda l a rtery and vein a t the ba se of the udde r . Area o f drainage An u s , udder , v u l va , umbi lica l area and media l s urface of the thigh . Efferent routes Media l il iac node s . N umber Two 42 In two l ambs and two ewes , two nodes we re recorded o n both sides . l ambs and one ewe had one node on the l eft side and two on the right . One l amb had one node on both sides , and another had one node on the right side and no node wa s found on the l eft . In one ewe , three nodes were demon strated on the l eft side and two on t he right , and another had four nodes on the l e ft side and three on the right . One ewe h ad two nodes on the l eft side and one on the right . Shape and Size ( see Figure 12) The nodes we re irregu l a r , ova l to kidney and dumbbe l l in s hape and of variabl e size . In l ambs , the nodes ranged from 5-37 mm in l ength , 5-10 mm in width and 3-5 mm in thic knes s and from 0.35-1.14 g in weight with a mean of 0.68 g . In ewe s , they varied from 4-30 mm in l engt h , 4-13 mm in width and 2-5 mm in thic knes s and from 0. 49-0.95 g in weight with a mean of 0. 75 g . 43 Figure 12 : SHAPE OF SUPERF I C I AL I NGU I NAL NODES LAMBS EWES Left Right Left Right C) � c::J 1 • Absent 0 (;::0 0 Oo o� 2. c 0 [§ C) 3 . c::::::::::> 0 . 0 C)r::::; 0 ()�or% 4. 0 0 0 Oo 0 5. 0 0 6. C) ()\:; t:fJ LEFT TRACHEOBRONCHIAL Loc at i on The l eft trac heobronch i a l nodes l i e crani a l to the ori g i n of the l e ft pri nc i pa l bronch u s . The l eft a zygos ve i n passes over these node s . Area of dra inage 44 Crani a l l obe of the l eft l ung (Al bert ine et a l , 1982) , trac hea , oesophagu s , med i a s t i num and heart . Secondary l ymphat i c ves se l s come from the i nconstant mi d d l e tracheobronch i a l l ymph node . Efferent route s Crani a l med i a s t ina l node s . Number In two l ambs , one node wa s recorded and another had two . Two ewe s had two node s . In one l amb and three ewes , three nodes were demonstrated and two l ambs and one ewe had four nodes . Sh ape and S i ze ( see Fi gure 13) The nodes were irregu l ar , tri angu l ar to ova l and ki dney i n s hape and of vari ab l e s i ze . I n l ambs , the nodes range d from 4-28 mm in l ength , 3-14 mm in wi dth and 2-8 mm i n t h i c knes s and from 1.35-2.41 g i n we i g ht wi th a mean of 1.78 g . In ewe s , they ranged from 4-30 mm i n l ength , 3-10 mm in wi dth and 2-7 mm in th i c knes s and from 0.73-2.12 g in we i ght wi th a mean of 1.28 g . 45 F i gure 1 3 : SHAPE OF LEFT TRACHEOBRONCHIAL NODES LAMBS EWES 1 . �a �0 2. Do c c:J6 d�o 3 . 00 4 . OD c=:Jo 0 5. C;:; g� 6. oo OC) CRANIAL TRACHEOBRONCHIAL Locat i on The c ran i a l t ra c heobronch i a l nodes l i e ventra l to the trachea l bronc h u s . Area of dra inage Cran i a l l obe of the ri g h t l ung , trac hea , oe sophagus and peri cardium . Efferent routes Cranial med i a st inal node s . Number In three l ambs and one ewe , one node wa s recorded . Two l ambs and three ewe s had two node s . In two ewe s , fo ur nodes were fo und , and in one l amb , s i x node s were demonstrated . Shape and Size ( see Fi gure 14) The nodes were irreg u l a r , ova l to k i dney in s hape and of vari ab l e size . In l ambs , the nodes ranged from 7-30 mm in l ength , 5-12 mm in width and 3-6 mm in t h i c knes s and from 0.45-2.84 g in we i ght wi th a mean of 1.28 g . In ewes , they va ried from 6-25 mm in l ength , 5-12 mm in wi dth and 2-8 mm in thic knes s and from 0.50-1.41 g in we i ght wi t h a mean of 0.91 g . 47 Figure 1 4 : SHAPE OF CRANIAL TRACHEOBRONCH IAL NODES LAMBS EWES 1 • C00\J 0 2 . 3 . oo 4 . 5. 6. 48 CAUDAL MEDIASTINAL Loc at i on The cauda l med i a s t i n a l n odes l ie i n the po stcardiac med i a s t i num between the thora c i c aorta a n d the oesophagus . Area of dra i nage 9 D i aphram , oesophag us , med i a st i num , peri card i um and part of the cauda l 1 obes 1 of both l ungs , dorsol atera l t horac i c wa l l between about the 6th and 13th r i b s . A l bert i ne et a l ( 1982 ) s how t hat t he node dra i n s a l s o the cauda l l obe of bot h l un g s . Efferent routes The efferent ves sel s j o i n the thorac i c duct ( La ndo l t et a l , 198 1 ) . Number In th ree l ambs and th ree ewes on l y one l a rge node wa s recorded . Another th ree l ambs and t hree ewes h ad one l a rge node and one sma l l node . Shape and S i ze ( see Fi gures 1 5 and 16 ) The l arge nodes were i rregul a r , e l ongated i n s h ape and the sma l l nodes were k i dney or banana i n s hape a n d of vari a b l e s i ze . In l ambs , t he l a rge nodes ranged from 68- 1 1 5 mm i n l ength , 9- 1 3 mm i n wi dth and 5-9 mm in th i c knes s and the sma l l nodes ranged from 1 2- 42 mm i n l ength , 6- 1 1 mm i n wi dth and a bout 5 mm i n th i c knes s and from 5 . 52-7 . 5 1 g i n wei g ht wi th a mean of 6 . 34 g . In ewes , the l a rge nodes ranged from 98- 1 32 mm i n l ength , 7 - 1 3 mm i n wi dth and 5-7 mm i n t h i c knes s a n d the sma l l n odes ranged from 5- 36 mm i n l ength , 5-9 mm i n wi dth and 3- 5 mm i n th i c knes s and from 3 . 85- 6 . 77 g i n wei ght wi t h a mean of 5 . 1 6 g . 1. Figure 15 S HAPE OF CAUDAL MEDIASTINAL NODES LAMBS 2 . 3. 4 . 5 . D 0 49 6 . 1 . 0 Figure 16 SHAPE OF CAUDAL MEDIAST I NAL NODES EWES 2 . 3 . 4 . 5 . 0 50 6 . HEPATIC Locat i o n The h epat i c n ode s a re s i tuated a round t he porta of t he l i ve r , i n a s soc i at i on w ith the porta l ve i n . Efferent routes 51 The e fferent ve s sel s form the hepat i c trunk wh i c h te rmi nates i n the end of the i nte s t i na l t run k . Number In four l ambs and two ewe s , two node s were recorded . Two l ambs and one ewe had three nodes , a n d i n three ewe s o n ly one node wa s found . Shape and S i ze ( see Fi gure 17 ) The n odes were ova l to k i dney i n s ha pe and of vari ab l e s i ze . In l ambs , the nodes ranged from 5-23 mm i n l e ngth , 4 - 1 5 mm i n w idth and 3- 10 mm i n t h i c kne s s and from 0.7 5-3.23 g i n we i g ht wi th a mean of 1.46 g . In ewes , they ranged from 4-28 mm i n l ength , 4- 16 mm i n wi d t h and 3- 10 mm i n t h i c kn e s s and from 0.89-2 . 17 g i n we i g ht wi th a mean of 1.32 g . 1 . 2 . 3 . 4 . 5 . 6 . Figure 1 7 : SHAPE OF HEPAT I C NODES LAMBS Oo <) oo oa 52 EWES 0 COLIC Locat i on 53 The co l i c nodes l ie both s uperfi c i a l l y on the ri ght s i de of the col on i c s p i ra l and a l so between t he i nd i vidua l coi l s . I nd i v i du a l nodes , a re present i n the proxi ma l part of the mesentery . Area of dra i n age The afferent ves sel s a re recei ved from the a s cend i ng co l on , caecum a nd i l eum . Efferent routes The efferent ves sel s go to the i n tes t i n a l trun k or , to the jejuna l trun k o r , to the other col i c l ymph nodes . N umber I n one l amb and two ewes , one node wa s recorded . One l amb and one ewe had t hree nodes . I n one l amb and two ewes , fo ur nodes were found . One l amb had f i ve nodes a nd another had n i ne . I n one l amb a n d o ne ewe , seven nodes were demonstrated . Shape and S i ze ( see F i gure 1 8 ) The nodes were i rreg u l a r , ova l i n s hape a n d of va ri a b l e s i ze . I n l ambs , the nodes ra n ged from 4- 42 mm i n l ength , 4- 22 mm i n wi dth and 3- 9 mm i n th i c knes s and from 2 . 60- 6 . 17 g i n wei g ht wi th a mean of 4 . 04 g . In ewes , t hey varied from 6- 39 mm i n l ength , 4- 1 9 mm i n wi dth and 2- 1 2 mm i n th i c knes s and from 1 . 1 4- 5 . 42 g i n wei g ht wi th a mean of 3 . 34 g . Figure 1 8 : SHAPE OF COLIC NODES LAMBS EWES 1 . ooo ODOc:> 2 . 3 . QDO 4. oo�oo 0 5 . 54 0 IlEOCOliC Locat i on 55 The i l eocol i c nodes a re s i tuated on t he i l eocol i c a rtery i n t he i l eoceaca l fol d . Area of dra i nage Caecum and i l eum . Efferent routes The col i c nodes o r , d i rect l y to the i ntes t i nal trun k . Number One l amb had one node and a nother had fou r . One l amb and o ne ewe h a d two nodes . One l amb a n d one ewe had three node s . I n one l amb a nd two ewes , f i ve nodes were recorded . I n one l amb and one ewe , seven nodes were demonstrated . I n one ewe , s i x nodes were found . Shape and S i ze ( see F i gure 1 9 ) The nodes were i rregul a r , ova l i n s h ape and o f vari a b l e s i ze . I n l ambs , the nodes ranged from 5- 3 3 mm i n l ength , 5- 16 mm i n w i dth and 3- 12 mm i n th i c knes s and from 2 . 5 1- 6 . 3 1 g i n wei ght wi th a mean of 4 . 86 g . I n ewes , they ra nged from 5- 46 mm i n length , 5-23 mm i n wi dth and 3- 1 1 mm i n t h i c knes s and from 1 . 6 1-7 . 1 3 g i n wei g ht wi t h a mean of 4 . 43 g . Figure 19 : SHAPE OF I L EOCOL I C NODES LAMBS ,_ OCJ 2 . � 0 C> 3· 0 00 4 . 0 o�o 5 . E WES f) 0 0 oo 0 56 JEJUNAL Location The jej una l nodes l ie in t he mesentery between the first centrifuga l and the l a st centrifuga l coi l s of the s piral l oop of the ascending co l on . A rea of drainage The jejunum and i l eum , l a st centrifuga l coil of ascending co l on . Efferent routes The efferent ves sel s form the jej una l trun k . Number 57 In one ewe , one node wa s recorded and a nother had five . In one l amb , two nodes were demonstrated a n d another two had five . In two ewes , six and seven nodes were recorded res pective ly a nd a nother two had eight . In two l ambs , el even nodes were demonstrated and a nother had thirteen . Shape and Size ( see Figu re s 20-3 1 ) The nodes were el ongated and ova l to kidney in shape and o f varia b l e size . In l ambs , the nodes ranged from 5- 540 mm in l ength , 5-38 mm in width and 2- 1 9 mm in t hic knes s and from 63 . 64- 90 . 4 1 g in weight with a mean of 7 4 . 68 g . In ewes , they ranged from 9-380 mm in l en gth , 5-28 mm in width and 3- 1 1 mm in t hickness and from 1 9 . 7 9-3 0 . 43 g in weight with a mean of 2 5 . 52 g . The weights of a l l t he nodes comprising s pecific groups from the six l ambs a n d six ewes examined initia l l y as wel l as t he weight of 50 individua l popl itea l nodes from a further 2 5 l ambs are p resented in Tab les 3 , 4 and 5 . 0 JEJUNI\L NODES . SHAPE OF F i gure 20 LAMB 1 D 58 \ F i gure 22 SHAPE OF JEJUNAL NODES LAMB 3 0 0 F i gure 23 SHAPE OF JEJUNAL NODES LAMB 4 0 0 0 6 1 Figure 24 SHAPE OF JEJUNAL NODES LAMB 5 62 F i gure 25 SHAPE OF JE JUNAL NODES LP..MB 6 63 Figure 2 6 SHAP E O F J EJUNAL NODES EWE 1 0 0 64 F igure 27 SHAPE OF JEJU�AL �DOES EWE 2 w c D 65 f i gure 28 S HAPE OF JEJUNA L NODE EWE 3 66 0 F i gu re 29 SHAPE OF JEJUNAL NODES EWE 4 67 Figure 30 SHAPE OF JEJUNAL NODES EWE 5 0 0 0 Q 68 F i gure 31 SHAPE OF J EJUNAL NODES EWE 6 69 ,. 7 0 Tabl e 3 . We i gh t { g ) ( i nc l ud i n g l eft and ri g h t ) of 19 g roups of l ymph nodes from s i x l ambs Lymph nodes 1 2 3 4 5 6 Mean Range Ma nd i bu l a r 0 . 70 0 . 72 1 . 7 1 2 . 2 1 1 . 4 1 1 . 01 1 . 29 0 . 7 0-2 . 2 1 Pa rot i d 3 . 09 2 . 50 3 . 30 3 . 37 1 . 7 4 1 . 98 2 . 66 1 . 7 4- 3 . 37 Latera l retropharyngea l 1 . 08 0 . 7 4 1 . 1 1 1 . 1 1 0 . 42 0 . 82 0 . 88 0 . 42- 1 . 1 1 Med i a l retropharyngea l 4 . 78 4 . 98 5 . 62 5 . 6 1 7 . 9 3 6 . 79 5 . 95 4 . 78- 7 . 9 3 s uperf i c i a l cervi c a l 5 . 89 5 . 1 5 6 . 02 5 . 32 5 . 69 3 . 58 5 . 28 3 . 58- 6 . 02 Proper a xi l l ary 0 . 18* 0 . 62 0 . 1 5* 0 . 64 0 . 4 1 0 . 40 0 . 46 0 . 30- 0 . 64 Popl i tea 1 2 . 1 1 1 . 67 3 . 28 2 . 0 1 2 . 07 1 . 58 2 . 12 1 . 58- 3 . 28 Is ch i a t i c 1 . 16 0 . 8 5 0 . 97 0 . 6 1 0 . 9 5 0 . 44 0 . 8 3 0 . 44- 1 . 1 6 Sub i l i ac 2 . 05 1 . 86 2 . 30 1 . 1 6 1 . 92 1 . 41 1 . 7 8 1 . 16-2 . 30 Superf i c i a l i ngu i n a l 0 . 59* 1 . 20 2 . 28 1 . 18 1 . 1 3 1 . 1 1 1 . 3 5 1 . 1 1-2 . 28 Rena l 0 . 5 1 0 . 3 3 0 . 50 0 . 68 1 . 23 0 . 62 0 . 6 5 0 . 33- 1 . 2 3 Med i a l i l i ac 3 . 07 1 . 28 3 . 38 2 . 88 2 . 28 1 . 12 2 . 34 1 . 12- 3 . 38 Cra n i a l tracheobronc h i a l 1 . 1 6 0 . 4 5 0 . 98 2 . 84 1 . 25 1 . 02 1 . 28 0 . 4 5-2 . 84 Left tracheobronch i a l 2 . 20 2 . 4 1 1 . 52 1 . 3 5 1 . 63 1 . 59 1 . 7 8 1 . 3 5-2 . 4 1 Cauda l med i a s t i na l 5 . 72 7 . 5 1 6 . 02 6 . 7 7 6 . 49 5 . 52 6 . 34 5 . 52- 7 . 5 1 Hepat i c 0 . 7 5 0 . 88 1 . 06 3 . 23 2 . 00 0 . 85 1 . 46 0 . 7 5- 3 . 23 Col i c 2 . 60 6 . 1 7 4 . 90 3 . 18 4 . 1 6 3 .2 1 4 . 04 2 . 60- 6 . 17 Il eoco 1 i c 3 . 48 5 . 80 2 . 5 1 4 . 96 6 . 3 1 6 . 07 4 . 86 2 . 5 1- 6 . 3 1 Jej u n a l 6 3 . 64 8 5 . 2 1 90 . 4 1 69 . 30 69 . 0 3 7 0 . 5 1 7 4 . 68 6 3 . 64- 90 . 4 1 * = Lymph nodes on l y present on the ri g h t s i de . 7 1 Tabl e 4 . We i ght { g ) of 50 popl i teal l ymph node s from 25 Romney l ambs Lamb Carca se We i gh t of We i ght of D i fference of we i g hts Comb i ned no . we i g h t { k g } l eft s i de ri g h t s i de between l eft a n d ri ght we i g ht 1 1 5 . 5 1 . 60 2 . 47 0 . 87 4 . 07 2 18 . 5 1 . 58 1 . 6 5 0 . 07 3 . 23 3 14 . 0 1 . 5 1 1 . 80 0 . 29 3 . 3 1 4 13 . 5 1 . 63 1 . 23 0 . 40 2 . 86 5 14 . 5 1 . 58 1 . 47 0 . 1 1 3 . 05 6 1 5 . 0 1 . 4 1 1 . 20 0 . 21 2 . 6 1 7 16 . 5 0 . 94 0 . 88 0 . 06 1 . 82 8 12 . 5 0 . 98 0 . 9 5 0 . 03 1 . 93 9 16 . 5 1 . 12 1 . 32 0 . 20 2 . 44 10 1 5 . 5 2 . 18 1 . 40 0 . 78 3 . 58 1 1 17 . 5 1 . 4 5 1 . 5 1 0 . 06 2 . 96 12 14 . 5 1 . 08 0 . 62 0 . 46 1 . 7 0 13 16 . 5 0 . 88 1 . 2 1 0 . 33 2 . 09 14 1 5 . 0 1 . 18 1 . 18 0 . 00 2 . 36 1 5 1 5 . 5 1 . 38 2 . 42 1 . 04 3 . 80 16 1 5 . 5 1 . 7 1 3 . 27 1 . 56 4 . 98 17 12 . 5 1 . 00 0 . 89 0 . 1 1 1 . 89 18 1 5 . 5 1 . 67 1 . 45 0 . 22 3 . 12 19 14 . 5 1 . 38 1 . 69 0 . 31 3 . 07 20 12 . 0 1 . 3 6 0 . 83 0 . 53 2 . 1 9 2 1 12 . 5 2 . 1 0 1 . 9 1 0 . 19 4 . 0 1 22 18 . 0 1 . 7 4 1 . 67 0 . 07 3 . 4 1 23 1 6 . 5 1 . 9 0 2 . 13 0 . 23 4 . 03 24 13 . 5 0 . 9 1 0 . 82 0 . 09 1 . 7 3 25 12 . 5 2 . 44 3 . 0 1 0 . 57 5 . 4 5 Mean 1 5 . 0 1 . 47 1 . 56 3 . 03 ( S . D 0 . 4 1 ) ( S . D 0 . 68 ) Ra nge o f d i fference o f we i ght between l eft and ri ght- - -0 . 00- 1 . 56 Ra nge of we i g ht s of i nd i v i dua l s - - - - - - - - - - - - - - - - - - - - - - - - 0 . 62-3 . 27 72 Tabl e 5 . We i ght ( g ) ( i nc l ud i ng l eft and ri g ht ) of 1 9 g roups of l ymph nodes from s i x ewe s Lymph node s 1 2 3 4 5 6 Mean Ra nge Mand i bul a r 1 . 6 8 1 . 80 0 . 58 1 . 12 1 . 89 1 . 2 1 1 . 38 0 . 58- 1 . 89 P aroti d 2 . 5 5 1 . 8 5 1 . 7 4 2 . 05 1 . 87 2 . 20 2 . 04 1 . 7 4-2 . 55 Lateral retropharyngeal 0 . 7 0 0 . 54 N* 0 . 9 5 1 . 90 0 . 49 0 . 92 0 . 49- 1 . 90 Med i a l retropharyngeal 2 . 93 2 . 12 1 . 2 4 1 . 33 2 . 73 2 . 7 7 2 . 19 1 . 24-2 . 93 S uperfi c i a l cervi ca l 3 . 7 5 3 . 02 5 . 19 4 . 55 5 . 35 4 . 49 4 . 39 3 . 02-5 . 35 P roper a x i l l a ry 0 . 07* 0 . 10 0 . 1 5 0 . 13 0 . 35 0 . 24 0 . 19 0 . 10-0 . 3 5 Popl i t ea 1 1 . 08 1 . 6 5 1 . 93 1 . 43 3 . 1 1 1 . 6 1 1 . 80 1 . 08-3 . 1 1 I sch i at i c 0 . 30 0 . 42 0 . 5 5 0 . 39 0 . 56 0 . 69 0 . 49 0 . 30-0 . 69 S ubi l i ac 1 . 72 1 . 78 2 . 13 1 . 45 1 . 65 2 . 08 1 . 80 1 . 45-2 . 13 S uperfi c i a l i ngu i na l 0 . 99 1 . 64 1 . 38 1 . 68 1 . 49 1 . 7 9 1 . 50 0 . 99- 1 . 7 9 Rena l 0 . 63* 0 . 23 0 . 33 0 . 39 0 . 33 0 . 30 0 . 47 0 . 23- 1 . 26 Med i a l i l i ac 2 . 02 2 . 20 3 . 17 2 . 48 3 . 39 1 . 66 2 . 49 1 . 66-3 . 39 C ran i a 1 t racheobronc h i a l 0 . 8 1 0 . 82 0 . 50 0 . 63 1 . 29 1 . 4 1 0 . 9 1 0 . 50- 1 . 4 1 Left t racheobronc h i a l 1 . 2 0 0 . 7 9 2 . 12 0 . 73 1 . 85 1 . 01 1 . 28 0 . 7 3-2 . 12 Caudal medi a sti n a l 4 . 72 3 . 8 5 5 . 92 4 . 14 6 . 77 5 . 5 5 5 . 1 6 3 . 85-6 . 7 7 Hepat i c 2 . 17 0 . 97 1 . 12 . 0 . 94 0 . 89 1 . 85 1 . 32 0 . 89-2 . 17 Col i c 4 . 48 2 . 42 5 . 42 1 . 1 4 4 . 45 2 . 1 1 3 . 34 1 . 1 4-5 . 42 I l eocol i c 5 . 92 3 . 18 7 . 13 5 . 50 3 . 22 1 . 6 1 4 . 43 1 . 6 1-7 . 13 Jejunal 29 . 89 19 . 7 9 22 . 56 30 . 43 24 . 39 26 . 04 2 5 . 52 1 9 . 7 9-30 . 43 * - l ymph nodes o n l y p resent on the ri ght s i de . N* = Lymph nodes not p re sent on e i t her s i de . As c a n be seen from the tab l e s a bove , the we i ght of jejuna l nodes of l ambs wa s approx imate ly t h reefol d that of ewe s . The combi ned we i ght of pop l i tea l nodes from a l l 3 1 l ambs had a range of 1 . 58 g to 5 . 45 g and the ran ge of i nd i v i d ua l nodes wa s from 0 . 62-3 . 27 g . These l atter re s u l ts a re s hown i n t he form of a h i stogram i n F i gure 32 s u perimposed on wh i ch i s an e s t i mate of t he i r pos s i bl e d i s tri but i on . Fi gure 33 i s the hypotheti ca l d i s tri buti on of wei ght of norma l and a bnorma l popl i te a l l ymph node . N umber F i gure 32 : D I STR I BUT ION OF WE I GHT OF POPL ITEAL LYMPH NODES OF LAMBS ,. ---- .... , ,. , ; , ; I \ , I I \ \ \ I , ' \ \ \ \ \ \ ' \ ' ' , ', ' , 0 0 . 2 5 0 . 5 0 . 65 0 . 8 0 . 95 1 . 1 1 . 2 5 1 . 4 1 . 5 5 1 . 7 1 . 85 2 . 0 2 . 1 5 2 . 3 2 . 45 2 . 6 2 . 7 5 3 . 0 3 . 1 5 3 . 3 3 . 45 We i gh t ( g ) D a ta from 2 5 l ambs Data from 6 i n i t i a l l ambs Hypothet i c a l d i s tr i but i on -....J w Figure 33 : HYPOTHET I CAL D I STR I BUT I ON OF WE I GHT OF NORMAL AND ABNORMAL POPL ITEAL L YMPH NODE Approximate Rel at i ve Frequency 0 0 . 6 1 . 2 1 . 8 2. 4 We i ght ( g ) 3 . 0 3 . 6 4 .2 4 . 8 D i s tr i b u t i on of normal D i s tr i but i on of abnorm a l ........ � 7 5 Tab l e 6 . Average mea s u rements of l ymph nodes of l ambs ( mm ) Left Ri ght Length Wi dth Th i c knes s Length Wi dth Th i c kn e s s Mand i bu l ar 18 9 5 19 10 5 Pa rot i d 22 12 6 27 10 6 Latera 1 retropharyngeal 1 5 7 5 14 7 5 Med i a l retropharyngea l 29 17 10 30 16 10 Supe rfi c i a l cerv i ca l 27 1 7 8 29 16 8 Prope r a xi 1 1 a ry 1 2 7 4 1 2 8 4 Popl i t ea 1 19 9 5 16 10 5 I sch i at i c 1 2 7 5 1 1 7 4 Subi l i ac 20 7 4 16 6 4 Supe rfi c i a l i ng u i n a l 2 3 8 4 12 8 4 Rena 1 1 2 7 5 9 6 5 Med i a 1 i l i ac 17 7 4 13 7 4 Length Wi dth Th i c kness Hepa t i c 1 3 9 6 Cran i a l tracheobronc h i a l 18 7 5 Left trac heobronc h i a l 1 4 7 5 Cauda l med i a s t i na l 63 9 7 Col i c 1 5 9 5 I l eocol i c 17 1 0 8 Jej u n a l 1 1 4 1 6 6 Ma nd i bu l a r Pa rot i d La tera 1 retropharyngea l Med i a 1 re tropha ryngea 1 Su perfi c i a l ce rvi cal Proper axi l l a ry Popl i teal I s c h i a t i c Su bi l i ac Su perfi c i a l i n g u i na l Re na 1 Me d i a 1 i l i a c He pat i c Cra n i a l trac heobronc h i a l Le ft tracheobronch i a l Ca uda 1 med i a sti na l Co l i c I l eocol i c Je juna 1 Tabl e 7 . Length 27 28 16 22 34 8 17 1 1 25 16 7 23 7 5 Average mea s urements o f l ymph node s o f ewe s ( mm ) Left Ri ght Wi dth Th i c kne s s Length Wi dth Th i c kn e s s -ro 5 18 -9- 6 10 5 26 1 1 6 9 6 1 4 8 4 16 6 22 12 6 1 6 7 35 17 6 6 3 7 5 2 1 1 7 17 1 1 6 7 4 10 6 4 9 4 30 8 6 7 4 1 4 9 4 5 3 8 5 4 7 3 39 8 4 Length W i dth Th i c kn e s s 1 9 9 7 1 3 7 5 1 4 7 4 1 14 10 6 2 1 1 3 6 1 5 10 6 1 1 1 1 2 7 7 7 From t he data s o far presented i t can be seen that t here a re cons i derabl e d i fferences i n the we i ght and s h a pe of d i fferent nodes , a n d i n the same nodes from d i fferent a n i ma l s . The we i g h t of j e j u n a l node of l ambs a ccounted for 63 percent of the tota l we i g ht of l ymph nodes exami ned , wh i l e the we i ght of je juna l node of ewe s on l y 40 percent of tota l we i g h t of t he l ymph node s e xami ned . The we i ght of j ej una l node s i n l ambs wa s at l ea s t ten t i mes g reater than a ny other nodes and i n s heep more than twi ce of that of any other nodes . Furthermore the re l a t i ve s i ze of these nodes in l ambs wa s t hreefol d greater than in ewe s . The we i g hts of the med i a l retropharyn gea l , proper ax i l l ary and i sc h i a t i c nodes of l ambs we re twi ce that of those from ewes . However , the we i g ht of a l l other nodes we re s i mi l a r i n both l ambs and ewes . From e xami nat i on of F i gure s 1 - 3 1 and Tabl es 6 and 7 i t can be seen that nodes such a s the ma nd i bu l a r and p roper a x i l l ary were re l a t i ve l y constant i n s hape , a l t hough there were d i fferences i n s i ze . Converse l y , n odes s u c h a s the med i a l i l i ac , s uperfi c i a l i ngu i n a l and jejuna l showed con s i derab l e vari a t i on i n both s ha pe and s i ze . I t s ho u l d a l so be noted that a l though most nodes cons i s ted of b i l atera l l y symmetri c a l bod i es , wi th the obv i ou s e xcept i on of those s u c h a s the hepat i c and jejuna l , i n one ewe the l atera l retropharyngea l nodes we re a bsent on both s i de s , i n two l ambs and one ewe the l eft proper a x i l l ary nodes were not present . I t wou l d a l so a p pear that a g roup of nodes cou l d e i ther be comb i ned i n one s i ng l e node or s ubd i v i ded i nto s evera l sma l l e r ent i t ie s , the mos t o bvi ous examp l e be i ng the j ej un a l . I n o n e ewe t he l eft i sc h i ati c node appeared to be s ubd i v i de d i nto three . 7R The tota l we i g ht of the l ymph nodes of each l amb and e a c h ewe expre s sed a s a proporti on o f body and c a rcase we i gh t , a re s hown i n Ta b l e s 8 and 9 re s pect i ve l y . Tabl e 8 . Tota l we i ght ( g ) of l ymph node s of l ambs a n d percentage of body and c arcase we i ght ( kg ) Lambs no . 1 2 3 4 5 6 Average Ra nge tota l we i g ht of l ymph node s 1 0 5 1 30 1 38 1 18 1 10 1 1 0 1 20 1 0 5 - 1 38 L i ve we i g ht 3 1 . 0 28 . 0 30 . 0 27 . 0 27 . 0 27 . 0 28 . 3 27 . 0- 3 1 . 0 Carcase we i g ht 1 3 . 8 1 3 . 5 1 4 . 0 1 2 . 0 1 2 . 4 1 1 . 2 1 2 . 8 1 1 . 2- 1 4 . 0 % of l ymph nodes to l i ve we i g ht 0 . 34 0 . 46 0 . 46 0 . 44 0 . 44 0 . 4 1 0 . 4 3 0 . 34- 0 . 46 % of l ymph nodes to carcase we i g ht 0 . 7 6 0 . 96 0 . 99 0 . 98 0 . 9 5 0 . 98 0 . 9 4 0 . 7 6- 0 . 99 Tabl e 9 . Tota l we i ght ( g ) o f l ymph nodes of ewe s a n d percentage of body a n d carcase we i ght ( kg ) Ewe s no . 1 2 3 4 5 6 Ave rage Ra nge Tota l we i ght of l ymph node s 68 49 63 6 1 67 59 6 1 49 - 68 L i ve we i ght 3 1 . 9 33 . 9 34 . 5 3 4 . 0 42 . 0 3 1 . 7 34 . 7 3 1 . 7 - 4 2 . 0 Carcase we i g ht 1 1 . 2 1 3 . 9 1 2 . 6 1 2 . 6 16 . 4 1 5 . 6 1 3 . 7 1 1 . 2- 1 6 . 4 % of l ymph nodes to l i ve we i g ht 0 . 21 0 . 1 4 0 . 18 0 . 18 0 . 16 0 . 19 0 . 18 0 . 1 4-0 . 2 1 % of l ymph node s to c arcase we i g h t 0 . 6 1 0 . 35 0 . 50 0 . 48 0 . 4 1 0 . 38 0 . 46 0 . 35-0 . 6 1 The average tota l we i g ht of l ymph nodes of l ambs wa s twi c e t hat of ewe s . A l though the l i ve we i g ht o f ewes wa s heav i e r than that o f l ambs the c arcases we i g hts were a l mo s t the same . Thu s the p roport i on of we i g hts of l ymph nodes to l i ve and carca se we i g ht of l ambs were a l so twi ce that of ewe s . D i fferences between the wet a nd d ry we i ght of the s i x g roups of l ymph nodes e xam i ned from t hre e l ambs a nd ewe s a re s hown in Ta b l e s 10 and 1 1 respect i ve l y . 7 9 Tabl e 1 0 . Wet a n d d ry we i ght o f l ymph nodes of l ambs Lambs no . Cra n i a l trac heobronc h i a l Left trac heobronc h i a l C a uda l med i ast i n a l Superfi c i a l cerv i ca l Pop l i tea l I s c h i ati c p = 0 . 1048 Wet we i g ht ( g ) 1 2 3 1 . 16 0 . 4 5 0 . 98 2 . 20 2 . 4 1 1 . 52 5 . 7 2 7 . 5 1 6 . 02 5 . 89 5 . 1 5 6 . 02 2 . 1 1 1 . 6 7 3 . 28 1 . 16 0 . 8 5 0 . 97 Dry we i ght ( g ) 1 2 0 . 24 0 . 08 0 . 47 0 . 45 1 . 1 3 1 . 6 1 1 . 03 0 . 89 0 . 40 0 . 3 1 0 . 2 1 0 . 14 Mean o f Range of d ry matter d ry matte r 3 % % 0 . 16 19 1 6 . 3- 20 . 7 0 . 30 20 18 . 7 - 2 1 . 4 1 . 29 2 1 1 9 . 8- 2 1 . 4 1 . 1 9 18 1 7 . 3- 19 . 8 0 . 63 19 18 . 6- 1 9 . 2 0 . 18 18 1 6 . 5- 18 . 6 80 Tabl e 1 1 . Wet a n d d ry we i g ht of l ymph nodes o f ewes Ewes no . Cran i a l t rac heobronch i a l Left t rac heobronc h i a l Ca uda 1 med i ast i na l s t Superfi c i a l c e rvi c a l Popl i tea 1 I s c h i a t i c p = 0 . 4335 Wet we i g ht ( g ) 1 3 0 . 8 1 0 . 82 1 . 20 0 . 7 9 4 . 72 3 . 8 5 3 . 7 5 3 . 02 1 . 08 1 . 65 I 0 . 42 6 1 . 29 1 . 85 6 . 7 7 5 . 3 5 3 . 1 1 0 . 56 Dry we i g ht ( g ) 1 3 0 . 1 1 0 . 1 5 0 . 18 0 . 14 0 . 66 0 . 66 0 . 46 0 . 49 0 . 18 0 . 37 I 0 . 07 Mean of Ra nge of dry matter dry matter 6 % % 0 . 22 16 1 3 . 6- 16 . 2 0 . 3 5 1 7 1 5 . 0- 18 . 9 1 . 1 6 16 14 . 0- 17 . 1 0 . 8 5 1 5 12 . 3- 1 6 . 2 0 . 5 1 18 1 6 . 4-22 . 4 0 . 12 19 1 6 . 7-21 . 4 The maxi ma l d i ffe rences of we i g hts of l ymph nodes from s i x l ambs a n d s i x ewes are s hown i n Ta b l e 12 . 8 1 8 2 Tabl e 1 2 . The max ima l d i fferences of we i ghts ( g ) of l ymph nodes from s i x l ambs and s i x ewe s : A compari son of i ntra a nd i n ter a n i ma l d i fference s . Name of Max ima l d i fference r�a xi ma 1 d i fference l ymph node between l eft and r i ght between t he s ame node nodes from the s ame a n i ma l from d i fferent a n i ma l s Lambs Ewes Lambs Ewe s Ma nd i bu l a r 0 . 6 5 0 . 44 0 . 96 0 . 87 Pa rot i d 0 . 64 0 . 6 5 1 . 17 0 . 69 Left ret ropha ryngea 1 0 . 6 1 0 . 44 0 . 69 0 . 9 5 Med i a l retropha ryngea 1 0 . 5 5 0 . 49 2 . 06 1 . 2 5 Superfi c i a l cervi c a l 0 . 32 0 . 85 1 . 36 1 . 5 5 Proper a xxi 1 a ry 0 . 28 0 . 16 0 . 33 0 . 17 Pop l i tea 1 1 . 60* 0 . 4 1 2 . 6 5 1 . 0 5 I s c h i at i c 0 . 32 0 . 1 5 0 . 60 0 . 29 Sub i l i ac 0 . 44 0 . 33 0 . 80 0 . 54 Superfi c i a l i ng u i n a l 0 . 50 0 . 22 0 . 79 0 . 46 Rena 1 0 . 7 7 0 . 1 1 0 . 86 0 . 5 3 Med i a l i l i ac 0 . 28 0 . 94 1 . 19 1 . 5 1 * These fi gu re s der i ved from 3 1 l ambs . Sta t i s t i c a l a n a l ys i s of these res u l t s s how that there a re no s i gn i fi cant d i fferences between the wet a nd dry we i g h t of d i fferent nodes ( P>O . l ) a nd thus the we i g ht of a node i s a sat i s factory i n d i rect mea s urement of i ts s i ze . Al though the mean range of dry matter pe rcentage of l ymph nodes of l ambs wa s s i mi l a r to ewe s , t he dry matter content of t he l ymph node s from l ambs wa s s i gn i f i cant l y ( P