Volume 26 | Issue 2 Article 9

1963 The yL mph Nodes and the Lymph Vessels of the Abdominal Wall, Pelvic Wall and the Pelvic Limb of Swine L. I. Saar Iowa State University

R. Getty Iowa State University

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Recommended Citation Saar, L. I. and Getty, R. (1963) "The yL mph Nodes and the Lymph Vessels of the Abdominal Wall, Pelvic Wall and the Pelvic Limb of Swine," Iowa State University Veterinarian: Vol. 26 : Iss. 2 , Article 9. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol26/iss2/9

This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. The Lymph Nodes and the Lymph Vessels of the Abdominal Wall, Pelvic Wall and the Pelvic Limb of Swine

L. I. Saar, Dr. med. vet., and R. Getty, D.V.M., M.S., Ph.D.*

I. INTRODUCTION Grau (2,4,5,6,8) discussed and modi­ This article is the continuation of pre­ fied Baum's terminology and grouped the viously published papers (11, 12, 13, lymph nodes into lymphocenters (6). 14) regarding the lymph nodes of swine Further re-examination and improve­ and their drainage areas. The details of ments on the nomenclature were made the "material and methods" have been by Grau and Boessneck (7) and Spira described and discussed previously (13, (16) by extending the terms used for the 14). domestic animals as well as to the pri­ mates (incl. man), the insectivora, the II. THE TERMINOLOGY OF THE chiroptera, the lagomorpha, and also to LYMPH NODES the rodentia. The term lymphocenter (lympho­ A review of the anatomy and the meat­ centrum), which has been discussed pre­ inspection textbooks and other publi­ viously by Saar-Getty (12), seems to be cations showed that in the past a variety the "key" to solve the difficult problems of terms were used to group the lymph involved in the nomenclature of nodes of the abdominal and the pelvic compara~ tive anatomy. wall and the pelvic limb regions. Due to changes made in terminology, In reference to the correspondence and by reorganizing the lymph node groups personal communications with Prof. Dr. into lymphocenters, the authors prefer H. Grau (1962-63), chairman of the re­ for the sake of brevity to discuss only the visory committee of the proposed new in­ terms used at present in Sisson-Grossman ternational anatomical nomenclature of (1953, 4th edition) and compare them the lymph apparatus, the general guide­ with the new nomenclature to be used. lines for the future terminology are In agreement with Grau and Boessneck basically those which were introduced by (7) and Spira (16), the lymph nodes of B!lum (1912 thm 1932), for the domes­ tic animals. the abdominal wall are grouped into four lymphocenters (Lcc), of which two of the lymphocenters, the lumbar and the iliac • From Iowa State University. Ames Iowa where Dr. Saar 1. Research Associate and Dr: Getty' is Pro· lymphocenter are found in association fessor and Head of the Department of Veterinary Anatomy. College of Veterinary Medicine. with the trunks and the main branches S~pported In part by Project No. 62. Veterinary of the abdominal aorta and the posterior Medical ~esearc.h Institute, Iowa State University. Apprec!ation IS extended to Miss Judith Mathew· vena cava. These lymphocenters are situ­ son, Medical Illustrator and Mr. Daniel J. Hillmann for artwork and photography. ated subperitoneal on the dorso-medial

Issue, No.2, 1963-64 97 side of the abdominal wall, being located inguinal lymph nodes situated along the ventral to the lumbar vertebrae. The other course of the external iliac vessels. The two lymphocenters, the subiliac and the posterior portion of the internal iliacs (Sis­ superficial inguinal lymphocenter are situ­ son-Grossman), located in the angle of ated subcutaneously (embedded in fat) divergence of the internal iliac arteries, on the lateral and on the ventral side of are called according to the new termi­ the abdominal wall. nology-the anterior sacral Inn. (Lnn. In swine the lumbar lymphocenter (Lc. sacrales (hypogastrici) ). lumbale) includes the lumbar aortic, the According to the new terminology the renal, the phrenico-abdominal, the uterine deep inguinal lymph nodes, which form and the testis lymph nodes, which in Sis­ the deep inguinal lymphocenter of the son-Grossman (15) are designated as the pelvic limb, are in . swine found to be lumbar nodes. absent. In man, the latter lymphocenter is The iliac lymphocenter(Lc. ilium located in the fossa iliopectinea, and in (commune» comprises the lateral and the horse, the cow, the dog, the cat, and the medial iliac lymph nodes of which the the guineapig, it is associated in close lateral iliacs are synonymous with the ex­ proximity to the femoral vessels, distal to ternal iliacs (Sisson-Grossman), while the the origin of the deep femoral artery. medial iliacs include according to Sisson­ The subiliac lymphocenter includes in, Grossman's terminology the anterior por­ swine, the subiliac lymph nodes only. In' tion of the internal iliacs and the deep Sisson-Grossman (15) they are called the:

LYMPH VESSELS: • Injeclion Silt -lJr!oralSub__ -CullneolRiloc:a,. ..,"'''' Nod,,: -Ned'" s...cutanl_ C Lftrol &optofieiol a Medii. Supll'fic:illl Dr InIwrmuKular

Figure I-Subcutaneous lymph vessels. The arrows indicate the direction of the lymph flow. Tramverse planes are drawn through the middle of the 11th and the 14th spine of the thoracic vertebrae. Muscles: A·masseter; B.brachiocephalicus; C·trapezius; D·omotransversarius; E.deep pectoral (prescapu· lar portion); H·sternohyoideus. Veins: a·external maxillary; b·internal maxillary; c·external jugular; d·internal jugular; e-cephalic· humeral; f·axillary; g·ascending cervical. Lymph Nodes: I-mandibular; 2·parotid; 3·accessory mandibular; 4·lateral retrophryngical; 5,5'·ventral superficial cervical; 7-dorsal superficial cervical; 8.8-medial superficial cervical; lo-axillares primae costae (costoaxillary); 12-subiliac ("prefemoral"); 13,superficial inguinal; 14-superficial popliteal; 14'-deep pop­ liteal. Other Stmctures: G·mandibular gland; the numbers from 5r through lfir refer to the position of the ribs.

98 Iowa State University Veterinarian LATERAL VI EW

Subart

Figure 2: Subcutaneous lymph vessels on the medial and lateral side of the pelvic limb. The arrows indi­ cate the direction of the lymph flow_ Lymph Nodes-12-subiliac; 13-superficial inguinal; 14-superficial popliteal; 14'-deep popliteal.

Issue, No. 2, 1963~4 99 prefemoral lymph nodes. The term "pre­ nodes, however, are not described by the femoral" is considered by the authors as latter author (15). somewhat unfortunate since the lymph nodes drain largely the subcutaneous III. THE LOCATION OF THE LYMPH dorso-lateral lumbar area of the trunk. In NODES fact, the subiliac lymph nodes appear to A. The Lymphoeenters of the Abdomi­ be rather closely associated with the com­ nal Wall mon iliac lymphocenter. The medial iliac 1. The lumbar lymphoeenter (Le. lymph nodes are found near the origin of lumbale) the deep circumflex iliac vessels. The a. The lumbar aortic Inn. (Lnn. lateral iliacs are situated on the anterior lumbales aortici) (Fig. 7 and 9) comprise branches of the deep circumflex iliac ves­ a dozen or more small lymph nodes scat­ sels and the subiliac lymph nodes are tered along the ventral and lateral (often located on the ventral branches. dorsal) side of the abdominal aorta and The superficial inguinal and the acces­ the posterior vena cava. They extend pos­ sory superficial inguinal lymph nodes of teriorly from near the renal vessels to the the male are preferably called in the caudal mesenteric artery. Anteriorly, female, the supramammary lymph nodes. these lymph nodes are often not clearly They represent the superficial inguinal distingUished from the renal lymph nodes lymphocenter (Lc. inguinale superficiale) and posteriorly it may be difficult to dif­ situated on the ventral part of the ab­ ferentiate them from the medial iliac dominal wall. lymph nodes. The size of the lymph nodes The lymphocenters of the pelvic wall varied from a few millimeters up to 2.0 (Lc. sacrale) are associated in general cm. in length. with the internal iliac vessels and their b. The renal Inn. (Lnn. renales) branches. They will be. described as the (Fig. 7) are found in association with the anterior, the internal and the external renal vessels. Usually there are 1-4 lymph sacral lymph nodes. nodes of approximately 0.25-1.5 em. in The anterior sacral lymph nodes (Lnn. size. sacrales (hypogastrici)) correspond in c. The phrenico-abdominal In. part with Sisson-Grossman's internal iliac (Ln. phrenico-abdominalis) (Fig. 7) is lymph nodes. namely with those lymph located posterior to the caudal branch of nodes which are situated in the angle of the phrenico-abdominal vessels on the divergence of the internal iliac arteries. lateral side of the iliopsoas muscle embed­ The internal sacral lymph nodes (Lnn. ded in fat. OccaSionally, in three out of sacrales interni) are not present in swine, 16 cases, this lymph node was present on although in the cow, the sheep and the the right side only and in one female it dog they may be found on the medial side was considered to be absent. The size of of the sacro-sciatic ligament. the lymph node varied from a few milli­ The external sacral lymph nodes (Lnn. meters up to approximately 1.0 cm. in sacrales externi) are situated lateral to length. the sacro-sciatic ligament and they in­ d. The uterine Inn. (Lnn. uter­ clude the anal and the ischiadic lymph ini) are found in the anterior part of the nodes of swine as described by Sisson­ broad ligament of the uterus, associated Grossman (15). The deep inguinal and with the utero-ovarian vessels. Usually the popliteal lymphocenters, of which in there are one or two lymph nodes of ap­ swine only the latter one is present are proximately 0.25 to 2.0 cm. in size. Oc­ associated with the pelvic limb. The pop­ caSionally the lymph nodes were found liteal lymphocenter includes the deep and to be present on one side only. or they the superficial popliteal lymph nodes. In were completely absent, or occasionally Sisson-Grossman (15) the popliteal and difficult to distinguish from the lumbar the tarsal lymph nodes are actually syn­ aortic lymph nodes. onymous with the superficial popliteal e. The testis In. (Ln. testis pro­ lymph nodes. The deep popliteal lymph prius) is found in the male along the

100 Iowa State University Veterinarian spermatic cord, in association with the in­ versus abdominis muscle, embedded in ternal spermatic vessels. The number, fat on the ventro-Iateral surface of the size and location of the lymph nodes iliopsoas muscle. Usually there are found varied, although one of the lymph nodes 1-3 small lymph nodes of variable size was found in 4 out of 12 cases near the from several millimeters up to approxi­ origin of the internal spermatic artery mately 1.5 cm. in length. Occasionally, }'\Then the latter vessel crosses the ureter. these lymph nodes were found to be ab­ (Size varied from 0.25 cm. up to 1.5 cm. sent on the left side (2 out of 16 cases) in length). Some of the testis lymph nodes and on the right side (lout of 16 cases). were situated on the proximal part of the In the cases listed above, the lateral iliac pampiniform plexus (2 out of 12 cases) Inn. appeared to be fused with the medial of variable size from 0.2 cm up to approxi­ iliac lymph nodes. mately 1.0 cm. in length. Furthermore, in 3. The subiliac lymphocenter (Lc. 2 out of 12 cases, a few minute lymph subilicum) nodes were present along the course of In swine, this lymphocenter in­ the internal spermatic artery. The lymph cludes only one lymph node group. The nodes were found to be absent in 4 out of subiliac Inn. (Lnn. subilici) (Fig. 1, 2, 3, 12 cases examined. 4, 5, 6, 7) form a larger sized elongated 2. The common iliac lymphocenter conglomerate of smaller lymph nodes on (Lc. ilium [commune]) the midline between the tuber coxae and a. The medial iliac Inn. (Lnn. the patella. These lymph nodes are situ­ ilici mediales) (Fig. 3, 5, 6, 7, 8, 9) are ated anterior to the tensor fasciae latae situated anterior and posterior to the muscle, embedded in fatty subcutaneous origin of the deep circumflex iliac artery tissue along the ventral branches of the along the lateral and medial side of the deep circumflex iliac vessels. Usually the external iliac vessels. Anteriorly the conglomerate of lymph nodes is 2-5 cm. lymph nodes extend up to the posterior in length and 1-2 cm. in Width, or some­ mesenteric artery. Often, they are not dis­ times there are present two or three tinguished clearly from the lumbar aortic smaller sized conglomerates of lymph lymph nodes. The lymph nodes situated nodes. posterior to the deep circumflex iliac ves­ 4. The superficial inguinal lympho­ sels were usually somewhat larger. They center (Lc. inguinale superfici­ formed a conglomerate, comprised of 3-7 ale) lymph nodes of approximately 0.5-3.0 In swine, this lymphocenter cm. in length. OccaSionally some of the includes two lymph node groups of which lymph nodes of the latter group extended in the male they are referred to as the anterio-Iaterally into the close vicinity of superficial inguinal Inn. and the accessory the lateral iliac Inn. by crossing over the superficial inguinal lymph nodes. In the deep circumflex iliac vessels. Thus, it was female, however. they are preferably difficult to distinguish clearly both of called the supramammary Inn. and the these groups. The anterior group of the accessory supramammary lymph nodes. medial iliac Inn. included 3-8 lymph a. The superficial inguinal Inn. nodes of variable size from a few milli­ (Lnn inguinales superficiales) (Fig. 2, 3, meters up to approximately 2.0 cm. in 4, 5, 6, 7 and 10) in the male are located length. on the ventral side of the abdominal wall, The division of the medial iliac Inn. situated laterally to the penis. They form into an anterior and a posterior group is an elongated conglomeration of approxi­ emperical, although on occasion it may mately 3-7 cm. in length and 1-2 cm. in be helpful to describe the lymph flow. width. They are associated mainly with b. The lateral iliac Inn. (Lnn. the anterior branches of the external ilici laterales) (Fig. 3, 5, 6, 7, 8, 9) are pudendal vessels which they cover ven­ found anterior to the cranial branches of trally. These lymph nodes are located the deep circumflex iliac vessels. They are mainly anterio-Iateral to the spermatic situated near the caudal edge of the tans- cord and to a lesser extent they extend

Issue, No.2, 1963-64 101 MEDIAL VIEW

Subcutaneous Lymph Vessels: ---Lateral -Medial Deep Lymph Vessels: --Intermuscular 01' Pelvic Cavity

• Injection Site

Figure 3: Subcutaneous lymph vessels of the medial and lateral side of the pelvic limb. The arrows indio cate the directions of the lymph flow. Lymph Nodes: 12·subiliac; 13·superficial inguinal; 13'.accessory superficial inguinal; 14·superficial popli· teal; 14'-deep popliteal; 15, 15'-external sacral; 16·antcrior sacral; 17, 17'·medial iliacs; IS·lateral i1iacs. Blood Vessels: h·abdominal aorta; k-external iliac; m·internal iliac; n·middle sacral; o-deep femoral; p­ femoral; q-deep circumflex iliac.

102 Iowa State University Veterinarian Figure 8: Ventral view o( the lumbo-sacral region including the supreficial inguinal Iympho­ center. The arteries are injected with red latex, the veins with yellow latex, and the lymph ves· sels are blue. (See legend on Figures 6 and 7).

Figure 9: Ventral view o( lumbo-sacral region (See leg· ends on Figure 6 and 7).

Figure 10: Ventral (abdominal) view o( the boar. Observe the afferents (rom the prepuce and medial surface o( pelvic limb terminating into the superficial inguinal Iymphocenter. posterio-medially. The caudal portion of difficult to distinguish clearly the acces­ the lymph node groups of the right and sory lymph nodes from the supramam­ left side lie in close proximity one to the mary lymph nodes because of the loose other, forming a v-shaped conglomeration arrangement of the conglomerate. of lymph nodes. B. The Lymphocenters of the Pelvic In the female, the superficial inguinal Wall Inn. are called the supramammary Inn. The sacral lymphocenter (Lnn. supramammarii). They represent a. The anterior sacral Inn. (Lnn. an elongated, loosely arranged conglom­ sacrales (hypogastrici) ) (Fig. 3, 5, 6, 7) erate of lymph nodes of 3-8 cm. in length are situated in the angle formed at the and 1-2.5 cm. in width, situated ventral left and the right internal iliac arteries, to the anterior branches of the external located near the origin of the medial sac­ pudenal vessels alon'g the lateral and the ral artery. Usually, there are 1-3 lymph posterior border of the caudal half of the nodes approximately 0.25 cm. up to 1.0 last mammary gland. cm. in size, which appear to form an un­ b. The accessory superficial in­ paired group of lymph nodes. guinal Inn. (Lnn. inguinales superficiales b. The internal sacral Inn. (Lnn. accessorii) of the male (Fig. 3) and the sacrales interni) include the lymph nodes accessory supramammary Inn. (Lnn. found medial to the sacro-sciatic ligament supramammarii accessorii) of the female along the internal iliac and the medial (Fig. 1) may be considered as the "split­ sacral vessels and their branches. How­ off" lymph nodes of the superficial in­ ever, in swine, there are no true internal guinal lymph nodes. In both sexes, the sacral Inn. present, although occasionally ac.cessory lymph nodes are found at a there are found in both sexes small lymph variable distance of approximately 5-15 nodes (Lnn. urogenitales) in the urogeni­ cm. anterior to the main group of lymph tal fold (plica urogenitalis) in association nodes along the subcutaneous abdominal with the umbilical artery. vein. In the female, the latter lymph nodes In seven castrated males, these lymph were located in 2 out of 9 cases on one nodes were found to be present on both side, and in lout of 9 cases on both sides sides in two cases. In 2 animals on the of the broad ligament of the uterus, as­ right side only, and in 3 additional cases, sociated with the proximal part of the um­ they were absent. The number (1-3), the bilical artery. size (approximately 0.5-1.5 cm.) and the In the male, small urogenital lymph distance (5-15 cm.) of the lymph nodes nodes of less than 0.5 cm. in diameter from the superficial inguinal lymph nodes were located in 3 out of 7 cases on the varied on each castrated animal. In three dorso-Iateral side of the seminal vesicle in boars, the accessory lymph nodes were the urogenital fold. present on both sides. In one case, they c. The external sacral lrin. (Lnn. were found on the left side only, and in sacrales externi) (Fig. 3, 4, and 5) are one boar, the latter lymph nodes were located on the lateral side of the sacro­ absent. sciatic ligament, covered by the gluteus The accessory supramammary lymph medius and the biceps femoris muscles. nodes of the female were found in four The lymph nodes, 1-5 in number, are out of eleven cases examined. In three found along the course of the internal animals, the lymph nodes were present iliac vessels in region between the great on both sides situated along the subcu­ ischiadic foramen (spatium ischiadicum taneous abdominal vein approximately 3- majus) and the posterior border of the 5 cm. anterior to the main group. The sacro-sciatic ligament. Usually, two rrumber of the lymph nodes varied from groups of lymph nodes may be dis­ 1-4 and the size was found to be approxi­ tinguished according to their position mately 0.5-1.5 cm. in length. In one case, whether anterior or posterior to the the lymph nodes were present on the left ischiadic spine. side only, and in four more cases it was The anterior group is found 2-3 cm.

104 Iowa State University Veterinarian posterior to the great ischiadic foramen. because of Its small size (usually less The size of the lymph nodes varied from than 0.5 cm. up to 0.75 cm.) it may be 0.25 cm. to 0.75 cm. in length. easily overlooked. Occasionally there were The posterior group is located 2-3 cm. present 2 or 3 small lymph nodes of less anterior to the posterior edge of the sacro­ than 0.5 cm. in size. In 17 out of 40 pelvic sciatic ligament, dorsal to the origin of limbs examined the deep popliteal In. was the caudal haemorrhoidal vessels. The found to be absent. Furthermore, ii1 lout size varied from 0.25 cm. up to 1.5 cm. in of 40 limbs examined, both the superficial length. and the deep popliteal lymph nodes were Occasionally, the external sacral Inn. not found to be present. formed a chain of 4-5 small lymph nodes IV. THE LYMPH VESSELS AND THE (approximately 0.5 cm. in length) along LYMPH DUCTS the internal iliac vessels. Furthermore, in 1. General Observations 2 out of 20 cases, the lymph nodes were The lymph vessels are closely associ­ found to be absent on the left side, and ated with the connective tissue in which in 4 out of 20 cases they were not present the lymph capillaries join to form three­ on the right side. dimensional IYI!lph vessel plexuses and Egehoj (3) described the presence of networks. In general, the size of the lymph the Ln. gluteus in 10% of the cases he vessels increase in the direction of the examined near the tuber ischiadicum on lymph flow, although the lymph vessels the medial side of the biceps femoris. This may branch and join again and form lymph node was not found to be present numerous collaterals before entering the in 40 limbs examined by the authors. lymph nodes. C. The Lymphoeenters of the Pelvic For descriptive purposes, the lymph Limb vessel networks are described as the The deep inguinal lymphocenter (deep "superficial lymph vessels," confined to inguinal lymph nodes) are absent in the skin and the subcutis and as the "deep swine. Only the popliteal lymphocenter lymph vessels," which follow the route of can be located on the pelvic limb of swine. the intermuscular connective tissue sheets. The popliteal lymphocenter (Le. popli­ This classification is rather emperical, be­ teum) includes in swine the superficial cause of the difficulties to distinguish (subcutaneous) and the deep (inter­ clearly the borderlines of the latter net­ muscular) popliteal lymph nodes. works. In general, however, the direction a. The superficial popliteal In. (Ln. of the lymph flow of the skin and the popliteus superficialis) (Fig. 1, 2, 3, 4, 5) subcutis differs from that of the under­ is located on the dorso-caudal surface of lying muscles and the fasciae. The super­ the gastrocnemius muscle, in a groove be­ ficial lymph vessels are found to flow to­ tween the biceps femoris and the semi­ gether along broad connective tissue tendinosus muscle. Usually, it is present sheets towards the subcutaneous lympho­ 2-3 cm. from the skin being embedded in centers, usually independent of the pat­ fat on the saphena parva vein. The size tern of the blood vessels. of the lymph node varied from 0.5 cm. up The deep lymph vessels, on the con­ to 3.0 cm. in length and occasionally a trary, appear to be closely associated with second smaller lymph node was found to the route of distribution of the blood ves­ be present. However, in 2 out of 40 pelvic sels. Although this observation may be limbs examined, they were absent. solely coincidental due to the fact that b. The deep popliteal In. (Ln. pop­ this may be the easiest way of passage liteus profundus) (Fig. 1, 2, 3, 4, 5) is along the intermuscular connective tissue located approximately 3-6 cm. cranio­ sheets. dorsal to the superficial popliteal Inn. In general, the lymph vessels of the along the course of the saphena parva skin and the subcutis of the posterior half vein, situated between the biceps femoris of the body, including the pelvic limb, and the semitendinosus muscle. The latter enter the subiliac and the superficial in­ lymph node is embedded in fat and often, guinal (supramammary) lymphocenters,

Issue, No.2, 1963-64 105 LATERAL VIEW

Subcutaneous Lymph vessels: -Lateral ----Medial

Deep Lymph Vessels: -.- Intermuscular or Pelvic Cavity

" Injection Site

Figure 4 Figures 4 and 5: The routes of the lymph How from the dorsal (anterior) area of the metatarso-phalangeal articulation (fetlock joint). The arrows indicate the direction of the lymph flow. Lymph nOMS: 12·subiliac; 13-superficial inguinal; 14-superficial popliteal; 14'-deep popliteal; 15, 15'-ex· temal sacral; 16-anterior sacral; 17, I7'-medial iliacs; IS-lateral iliacs_ Blood vessels: h-abdominal aorta; m-internal iliac; n-middle sacral; o-deep femoral; p-femoral; q, q'­ ventral and anterior branches of the deep circumflex iliac; r-external pudendal.

106 Iowa State U niversity Veterinarian MEDIAL VIEW =------...

SubcutaneOUS Lymph Vessels: _L.oterol -Medial Deep L¥mph Vessels: -.-Intermuscular Of PelvIc cavity 6/rtectionSite

Figure 5 Directions of lymph flow: l\l'-efferents of the external sacral Inn. follow the internal iliac vessels. They come from the popliteal Iymphocenter (l\I) via the route of the ischiadic nen'e; O-eflerents ,of the popli. teal Jymphocenter which follow the medial circumflex femoral to the deep femoral vessels. The popliteal Inn. receive afferents from the lateral side of the limb; P-eflerents coming from the medial side of the limb along the saphena magna. They follow the course of the femoral vessels. Q-elTerents of the subiliac Inn. passing along the deep circumflex iliac vessels to the medial and lateral iliac lymph nodes; R-elferents of the external pudendal vessels.

Issue, No. 2, 1963-64 107 while these of the anterior half of the 5, and 10) receives mainly the subcutan­ body terminate into the dorsal and the eous lymph vessels from the posterior ventral superficial cervical lymph nodes half of the body, including the pelvic limb, (the superficial cervical lymphocenter). which are not drained by the subiliac The line of the division of the subcu­ lymphocenter. The afferent lymph vessels taneous lymph flow, into anterior and originate from the skin, the subcutis and posterior direction, was established in the cutaneous trunci muscles of the eight animals. It was found that by plac­ latero-ventral half and the ventral part of ing imaginary transverse planes through the posterior half of the body, and from the middle of the spines of the 11th and the lateral (caudal) Va of the thigh and the 14th or 15th thoracic vertebrae (Fig. the skin of the tail. Furthermore, lymph 1) and by connecting them with an vessels are received from the skin areas oblique line drawn from anterior (dorsal) of the lateral side of the pelvic limb (dis­ to posterior (ventral) along the lateral side tal to the stifle joint) and from the entire of the body, it was possible to approxi­ medial side of the pelvic limb including mate the directions of the subcutaneous the deeper structures of the digits, acces­ lymph flow (Fig. 1). The terms "posterior sory digits and the bulbs of the claws. half" and "anterior half" of the body will The superficial inguinal lymph nodes be used as cranial or caudal to this receive lymph vessels also from the rectus oblique line described. abdominis muscle and in the male from 2. The lymph drainage areas of the. the skin and the subcutis of the penis and lymphocenters preputium (Fig. 10) and the cranial and a. The subiliac lymphocenter (Fig. caudal preputial muscles and from the 1 and 2) is the main gathering place of subcutis of the scrotum. In the female, the lymph vessels of the skin, the subcutis the supramammary (superficial inguinal) and the cutaneous trunci muscles of the Inn. drain the subcutis of the vulva and dorsal border line of the drainage area the posterior four or five (out of six) extending from the root of the tail up to mammary glands. Occasionally, afferents the spine of the 11 th thoracic vertebrae. may be received from the femoro-patellar It then turns caudo-ventrally, along the joint capsule. course of the 11th or 12th rib, close to the The efferent lymph vessels (Fig. 3, 5, 6, costochondral junction and follows ap­ 7, 8) follow the course of the external proximately a line drawn posteriorly in pudendal vessels (pudendo-epigastric the direction of the "knee fold" (patella). trunk) to the deep femoral vessels and Posteriorly, the drainage area of the subi­ continue anteriorly along the external liac lymphocenter covers approximately iliac vessels to the common iliac lympho­ two-thirds of the skin and the subcutis of center. the thigh and the pelvic region. This area c. The popliteal lymphocenter (Fig. of drainage is thus anterior to the line 1, 2, 3, 4, 5) situated along the saphena drawn from the root of the tail cranio­ parva vein, appears to be intercalated ventrally towards the proximal Va of the along one of the routes of the lymph flow tibia and it includes also a skin area a from the areas of the tarsus, metatarsus few inches wide, along the cranio-medial and the digits. In general, this lympho­ border of the thigh and the medial side center receives the superficial and the of the stifle joint. In a few cases, afferents deep lymph vessels from regions associ­ are received also from the femoro-patellar ated with the distribution of the branches joint capsule. The efferent lymph vessels of the saphena parva vein. The afferent of the subiliac lymphocenter (Fig. 3, 5, 6, lymph vessels originate from the skin 7 and 8) follow the course of the ventral and the subcutis of the posterio-Iateral branch of the deep circumflex iliac vessels and the posterior (plantar) areas of the to the common iliac lymphocenter (the leg, distal to the tarsus, and it includes medial and the lateral iliac lymph nodes). also the subcutis of the bulbs of the calws. b. The superficial inguinal (supra­ Lymph vessels are also received from the mammary) lymphocenter (Fig. 1, 2, 3, 4, skin of the anterior (dorsal) surface of the

108 Iowa State University Veterinarian digits, which follow the course of the lymph nodes follow the course of the in­ dorsal ramus of the saphena parva vein. ternal iliac vessels and terminate into The popliteal lymphocenter receives the the medial iliacs and the anterior sacral deep lymph vessels of the posterior lymph nodes. (plantar) portion of the leg (distal to the The anterior sacral lymph nodes may tarsus). These afferent lymph vessels receive the lymph vessels from all of the originate from the muscles, the tendons, areas described for the external sacral the ligaments and the joint capsules of lymph nodes. Furthermore, lymph vessels the digits and the tarsus. are received also from the urinary and the The efferent lymph vessels of the pop­ genital organs and from the urogenital liteal lymphocenter follow two routes lymph nodes (internal sacrals). The (Fig. 3, 4, and 5), one along the course lymph vessels of the muscles of the tail of the saphena parva vein (Fig. 3, 4, and and those of the vulva and the vagina 5: 0) along the medial circumflex femoral terminate also in the anterior sacral vessels to the deep femoral vessels to lymph nodes. OccaSionally, some of the terminate finally into the medial and lymph vessels, which follow the course of lateral iliac lymph nodes. Secondly, some the external iliac vessels, by-pass the post­ of the lymph vessels, however, follow the terior group of the medial iliac lymph route of the ischiadic nerve (Fig. 3, 4, nodes and go to the anterior sacral lymph and 5:M) to the caudal gluteal vein. Usu­ nodes. ally the later lymph vessels enter the ex­ The efferents of the anterior sacral ternal sacral lymph nodes, although they lymph nodes terminate into the me·dial may skip one of these lymph nodes and iliac lymph nodes. follow the course of the internal iliac e. The common iliac lymphocenter vessels (Fig. 5: M') to terminate into the (Fig. 3, 5, 6, 7, 8, 9) which includes the medial iliac or sometimes also into the medial and the lateral iliac lymph nodes, anterior sacral lymph nodes. appears to be the main gathering place d. The sacral lymphocenter of for the lymph vessels of the posterior part swine includes mainly the anterior and of the body. The medial iliac lymph nodes the external sacral lymph nodes. The uro­ are the most prominent ones. genital lymph nodes (internal sacrals) are usually absent. First, they receive the efferents from The etxernal sacral lymph nodes (Fig. the other lymphocenters and the lymph 3, 4, 5) receive lymph vessels from the nodes in that area. The efferents of the skin and the subcutis of the caudo-dorsal subiliac lymphocenter follow the ventral areas of the pelvic region including the branch of the deep circumflex iliac vessels skin areas in the vicinity of the anus. The to the medial and the lateral iliac lymph deep lymph vessels arrive mainly along nodes. The efferents of the superficial in­ the course of the branches of the caudal guinal (supramammary) lymphocenter and cranial gluteal and the caudal take the route to the iliac lymphocenter haemorrhoidal vessels. via the external pudendal (pudendo-epi­ Thus, afferents are received in part gastric trunk) and the deep femoral ves­ from the deep, the middle and the super­ sels. The latter efferents are joined by the ficial gluteal and from the proximal third lymph vessels, which come from the pop­ of the biceps femoris and the semitendi­ liteal lymphocenter along the saphena nosus muscles. The lymph vessels of the parva and the medial circumflex femoral gemelli, the quadratus femoris and the vessels and follow the deep femoral ves­ internal obturator muscles enter also the sels to the medial iliac lymph nodes. The external sacral lymph nodes. Further­ efferents of the sacral lymphocenter reach more, as described preViously, the latter the medial iliac lymph nodes via the in­ lymph nodes receive also in part some of ternal iliac vessels. The lymph vessels of the efferents of the popliteal lympho­ the caudal mesenteric lymphocenter (Lnn. center. mesenterici caudals) follow the course of The efferents of the external sacral the branches of the caudal mesenteric

Issue, No.2, 1963-64 109 artery and enter, the medial iliac or the the urogenital lymph nodes are present, lumbar aortic lymph nodes. some of the lymph vessels may pass first Secondly, the common iliac lympho­ to these lymph nodes. In the female the center receives afferents directly from the urogenital lymph nodes receive afferents deeper structures of the abdominal and from the cervix uteri and from the the pelvic wall, from the pelvic viscera vagina. The lymph vessels of the ovaries, and from the pelvic limb along the route the uterine tubes, the uterus, the cervix, of the blood vessels, nerves, and the con­ the vagina and the vulva terminate, in nective tissue sheets. general, directly into the medial iliac The lateral iliac lymph nodes (Fig. 3, lymph nodes. However, some of the lymph 5, 6, 7, 8, 9) receive afferents via the vessels of the ovaries and the uterine anterior branches of the deep circumflex tubes may go to the lumbar aortic or to the' iliac vessels from the dorsal and dorso­ uterine lymph nodes, whereby the latter lateral areas of the external and the in­ lymph nodes (when present) receive ternal oblique muscles and from the distal lymph vessels also from the anterior half and caudal portions of the transversus of the horns of the uterus. Their afferents abdominis muscle, including the caudo­ enter the medial iliac lymph nodes. dorsal regions of the peritoneum. Further­ The lymph vessels of the testicles fol­ more, afferents are also received from the low the course of the internal spermatic posterior parts of the iliopsoas and the vessels. They enter the medial iliacs or psoas minor muscles. the lumbar aortic lymph nodes. In cases The medial iliacs receive lymph ves­ in which the testis lymph nodes are pres­ sels from the urinary bladder, the urethra ent, they go first to the latter lymph nodes. and the accessory genital glands. Some of Finally, the medial iliac lymph nodes these vessels may also go to the anterior receive lymph vessels directly from all the sacral lymph nodes. II), cases, in which deep structures of the pelvic limb which

Figure 6 Figures 6 and 7: Ventral view of the lumbo·sacral area. The subiliac lymph nodes are seen by dissecting a portion of the external and interal oblique muscles. Lymph nodes: I,P·renal; 2·phrenico·abdominal; 3·lumbar aortic; 4·1ateral iliac; 5·anterior sacral' 6.medial iliac (In. Fig. 7 they are enclosed into an area surrounded by a dotted line); 12·subiliac; 13.~uperficial inguinal (supramammary).

110 Iowa State University Veterinarian VENTRAL VIEW

Figure 7 Other Structu.,.es: A-posterior vena cava; B·abdominal aorta; C,C'-right and left kidney; D·i\iopsoas m.; [·transversus abdominis m.; F-rectus abdominis m.; H-adductor m.; ]-symphysis pelvis; K-internal oblique m.; L-tensor fasciae latae m.; a·splenic lymph duct; b-hepalic lymph duct: (a and b form the coeliac lymph trunk); c-cranial mesenterir lymph trunk; e·renal vessels; f·lumbar lymph ducts (trunks); g­ caudal mesenteric artery; h-anterior branches of the deep circumflex iliac; i·ventral branch of the deep circum Hex iliac; j.internal iliac vessels; k·middle sacral artery; I·external pudendal a.; m·femoral a.; n­ deep femoral a.; o-continuation of the cisterna chyli (thoracic duct); y-coeliac a.; q-deep circumflex iliac vessels; r-cranial mesenteric a.; s-cisterna chyli; t-elTerents fmm subiliac Inn.; u-elTerents from superficial inguinal Inn.; v-efferents from deep structures of the pelvic limb: w-efferents from the popliteal Iympho­ centrer; x-elTerents from the external sacral Inn:; y.elTernts from the tail, the anus and the vulva.

Issue, No. 2, 1963-64 111 include the muscles of the hip, the thigh, on the medial side of the limb to the the leg and the foot, and from the ten­ superficial inguinal lymph nodes (Fig. 10), dons, the ligaments, the fasciae and from or in two cases the latter efferents joined the joint capsules. Although the lymph the superficial lymph vessels on the vessels of the bones (periosteum) were cranio-Iateral side of the limb and entered not demonstrated in this investigation, it the subiliac lymphocenter. must be assumed that they too terminate The large number of lymph vessels into the medial iliac lymph nodes. These which enter the common iliac lympho­ lymph nodes also received afference from center form an extensive network in the the posterior portions of the sublumbar region of the divergence of the abdominal muscles (psoas minor, iliopsoas, quadra­ aorta and the posterior vena cava. The tus lumborum) and from the longissimus efferents of this lymphocenter continue" dorsi muscle. anteriorly as a plexus of lymph vessels The lymph vessels of the medial and and they incorporate the lumbar aortic the plantar side of the digits choose usu­ lymph nodes located dorsal and ventral to ally the course along the saphena magna the large blood vessels. From this lymph vein to the femoral vessels (Fig. 4 and vessel network may arise one to three 5). The lymph vessels of the dorsal, the larger sized lymph vessels or ducts ("lum­ lateral and the plantar side of the digits bar trunks") which may branch and join follow the route of the saphena parva vein again and form collaterals (Fig. 7). One along the lateral side of the leg to the of these lumbar ducts are usually found popliteal lymphocenter (Fig. 4 and 5), on the left dorso-Iateral side of the aorta, while other deep lymph vessels of the dig­ and as it widens gradually it continues its join the course of the branches of the anteriorly as the "cisterna chyli." Another anterior and posterior tibial vessels up to "lumbar duct" may be found on the right the popliteal artery and vein (Fig. 4 and lateral side of the posterior vena cava. 5). These lymph vessels continue their This duct turns usually dorso-cranially to course along the femoral vessels to the the posterior vena cava and it joins medial iliac lymph nodes. Furthermore, eventually the left lumbar duct a few the deep and the superficial lymph vessels centimeters posterior to the left renal of the digits may join also, as discussed artery. Sometimes, a third "lumbar duct" previously, the superficial lymph vessel may be identified along the right ventro­ network on the medial side of the pelvic lateral border of the abdominal aorta, as limb (Fig. 2, 3, 4, 5, and 10) and termi­ being the "ventral branch" of the right nate into the superficial inguinal lympho­ lumbar duct. This duct terminates into center (superficial inguinal lymph nodes). the large visceral lymph trunks which are The lymph vessels of the hip joint fol­ formed by the confluence of the coeliac low the course of the latero-proximal and the cranial mesenteric lymph trunks. ramus .of the lateral circumflex femoral This common lymph trunk takes a sharp vessels to the femoral artery and continue turn dorsally through a slit (space) found along the external iliac vessels to the between the diverting abdominal aorta medial iliac lymph nodes. and the posterior vena cava to enter the The efferents of the stifle joint (the cisterna chyli (Fig. 7 and 9). femoro-tibial and the femoro-patellar Some of the efferents of the common jointS) are associated mainly with the iliac lymphocenter, namely these of the middle genicular artery and vein, which lateral iliac lymph nodes course anteriorly are the branches of the popliteal vessels. to the phrenico-abdominal lymph nodes However, the lymph vessels may follow (Fig. 7 and 9), which they may enter or also the routes of the proximal medial and by-pass to terminate into the renal or the lateral and the distal medial and lateral lumbar aortic lymph nodes, or they may genicular vessels to the popliteal artery terminate into the cisterna chyli. and vein. Some of the lymph vessels of the The cisterna chyli (Fig. 7) represents femoro-patellar joint take the route along a very irreguladyshaped and greatly en­ the subcutaneous lymph vessel networks larged and bulged common lymph trunk

112 Iowa State University Veterinarian for the visceral and the lumbar lymph routes taken from the lymph drainage trunks. It is situated mainly along the area. The medial iliac lymph nodes re­ left dorso-Iateral border of the abdominal ceive lymph vessels from all the deep aorta, extending from a few centimeters structures of the pelvic limb, which in­ posterior to the renal artery up to the cludes the muscles, the tendons, the liga­ aortic hiatus. The largest diameters esti­ ments, the joint capsules and the con­ mated on the lymph filled posterior part nective tissue sheets. These lymph vessels of the cisterna chyli varied from 0.25 cm. follow mainly the course of the branches up to 1.25 cm. The cisterna chyli con­ of the femoral and the deep femoral ves­ tinues anteriorly through the diaphragm sels and continue along the external iliac into the thoracic cavity as the "thoracic artery and vein to the medial and the duct." The course of the latter duct and lateral iliac lymph nodes. its relationship to the large blood vessels The deep inguinal lymphocenter is including the variations of termination found to be absent in swine. In man, the into the left brachiocephalic vein (vena horse, and occasionally also in the cow anonyma) will be described in an article and the dog the latter lymphocenter is to follow. found in association with the femoral ves­ f. The lumbar lymphocenter (lum­ sels, distal to the origin of the deep bar aortic, renal and phrenico-abdominal femoral vein and artery. lymph nodes) and their remaining affer­ ents will be included in a publication in REFERENCES 1. Baum, H.: Betrachtungen iiber die Arbeit von preparation about the coeliac and the Postma, "Das Lymphgefliss-System des Schwel­ cranial and caudal mesenteric lympho­ nes". Z. f. Fleiseh-u. Milchhyg., 39: 133-140. 1929. centers of the abdominal cavity. 2. Baum. H. und Grau, H.: Das Lymphgefliss· System des Schwelnes. Verlagsbuchhandlung V. DISCUSSION AND SUMMARY Paul Parey:, Berlin. 1938. 3. Egehoj, J.: Das Lymphgefiiss-Sy:stem des The findings reported in this study on Schweines, Z. f. Flelschu-u. Milchhyg., 47: 333-341; 353-360, 373-378. 1937. living (anesthetized) swine on the direc­ 4. Grau, H. Zur Benennung der Lymphknoten, Hier: Die Lymphknoten des Beekenelnganges tions of the lymph flow in the abdominal und der BeckenhOhle. Berl. und Miinch. Tier­ and the pelvic wall and the pelvic limb arztl. Wschr., 237·241. 1941. 5. Grau. H.: Zur Benennung der Lymphknoten. with "Evans-Blue" (T-1824)* are in basic Hier: Die Lymphknoten der Beckenwand und des Brusteinganges. Berl. und MUnch. Tierlirztl. agreement with the results achieved on Woehr., 180-181. 1942. 6. Grau, H.: Das Lymphgefass·System. In: Ellen­ the non-living animals by other investi­ berger-Baum. Handbuch der vergl. Anatomie der Haustiere, 18. Auflage. Springer-Verlag, Berlin. gators. 1943. 7_ Grau, H. und Boessneck, J.: Der Lymphapparat. The common iliac lymphocenter ap­ In: von KUkenthal, W.: Handbuch der Zoologie. 8. Band/25 Lieferung, Walter de Gruyter & Co., pears to be the main area of confluence Berlin, 1960. of the lymph vessels of the posterior 8. Grau, H. Prinzipielles und Vergleichendes Uber das Lymphgefliss-System. Referat analasslich portion of the body. It receives afferents des 66. Internisten Kongress, Wiesbaden. Son­ derdruck LXI aus: Verhandlungen der Deutschen from the sacral, the subiliac, the super­ Gesellschaft fUr innere Medizin. Verlag J. F. Bergmann. MUnehen. 1960. ficial inguinal (supramammary) and the 9. Jossifow, J. M.: Das Lymphgefiiss-System des Schweines. Anat. Anz., 75:91-104. 1932. popliteal lymphocenters. The subiliac and 10. Postma, C.: Das Lympbgefass-System des Schweines, Z. f. Fleisch-u. Milchhyg., 38:354·151. the superficial inguinal (supramammary) 1928. lymphocenters are confined mainly to the 11. Saar, L. I. and ~etty, R.: The Lymphatic Sys­ tem. I.S.U. Vetennanan, Vol. 24, No. 3:146-151. drainage of the skin and the subcutis. 1962 12. Saar, L. I. and Getty, R.: Nomenclature of the Furthermore, in the female, the supra­ Lymph Apparatus. I.S.U. Veterinarian, Vol. 25. No. 1:23-29. 1962. mammary lymphocenter receives lymph 13. Saar, L. I. and Getty. R.: Lymph Nodes of the Head. Neck and Shoulder Region of Swine. I.S.U. vessels from all but the first two (anter­ Veterinarian, Vol. 25. No.3: 120·134. 1962·63. ior) mammary glands. 14. Saar. L. I. and Getty, R.: The Inter-Relationship of the Lrmph Vessel Connections of the Lymph The lymph nodes of the sacral and the Nodes 0 lhe Head. Neck and Shoulder Region of Swine. Am. J. Vet. Res.• (in print). 1964. popliteal lymphocenters are relatively 15. Sisson, S. and Grossman. J. D.: Anatomy of the Domestic Animals. 4th edition. Press of W. B. small and inconsistant. The afferent Saunders Co.. Philadel",hla. 1953. 16. Spira, Anneliese: Ole Lymphknotengruppen lymph vessels of these lymphocenters (Lymphocentra) bei den Saugern-Homologhie. represent often only one of the several rg6f~versuch. Inaug. Dissertation. MUnchen. 17. Zielzschmann. 0.: Das Lymphsystem. In: Schon. berg, F. und Zietzschmann, 0.: Die AusfUhrung • T-1824 ("Evans-Blue"); Allied Chemical Co., New der Tierarztlichen Fleischuntersuchung. Paul York, New York. Parey In Berlin und Hamburg. 1958.

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