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Proctologic postulates from an anatomic standpoint
PROCTOLOGIC
POSTULATES
FROM AN ANATOMIC
STANDPOINT ARRANGEMENT
OF ANORECTAL SURGICAL
MUSCULATURE
AS USEFUL
LANDMARKS
CHELSEA EATON, M.D. Attending
ProctoIogist,
HighIand and BerkeIey Hospitals
OAKLAND,
CALIFORNIA
A
LTHOUGH anatomy does not change, anatomic concepts may, and, when they do, the surgeon is first to be concerned. Now that recent discovery indicates that the anorecta1 muscuIature is arranged as a web, rather than as a series of muscuIar rings as has been Iong supposed, there are many inferences to be drawn in regard to the surgica1 drainage of ana infection. The soIution of probIems reIevant to the treatment of the cIinica1 entities commonIy termed hemorrhoids, fissure, ulcer, abscess, IistuIa, stricture, etc., demands two things: First, the recognition that these entities are various manifestations of infection of the ana gIands; second, that their development is conditioned by the spacia1 reIationship of these gIands to the surrounding anorecta1 muscuIature with its encIosed tissue spaces. Wh en these entities are Iooked upon as infections and when the arrangement of the surrounding tissues is recognized, appropriate methods of drainage may be instituted in a precise manner. This manner wiI1 be appropriate, precise and, indeed, effective because the operator who possesses this knowIedge is the onIy one who can profit by the guidance of a number of morphoIogica1 deviations of contour of the anorectum that shouId serve as indispensabIe surgica1 Iandmarks. The correIation of these factors of infection and anatomy wiI1 provide such a workabIe concept that the surgeon may make IogicaI deductions as to the appropriate methods of treatment. Although there is a wide recognition of the etioIogic rBIe of the ana gIands in the 64
production of ana infection, and while most practitioners recognize that the above mentioned clinica entities arise from this consource, we may expect unIimited troversy in this regard. Here, we are chieffy concerned with showing how these gIands tit into the anatomic scheme when pathoIogic changes occur and demand repair. However, we may point out the fact that, starting with Morgagni, a succession of investigators have incriminated these gIands as the provocative agents for the cIinica1 entities.ls2p3 Further ampIification of this factor of infection must be deferred unti1 we consider the arrangement of the anorecta1 muscuIature, the spaces in which these gIands are situated and the paths to which their infection may gain access. In order to gain a conception of the arrangement of the anorecta1 muscuIature, we must first examine the anatomic contributions that form our Iegacy from the we must make certain past; secondIy, deductions from that bioIogic Iaw which states that structure tends to adapt itseIf to function. In other words, we shouId attempt to corroborate and, if possibIe, harmonize the arbitrary, uncorreIated contributions of supposed anatomic facts with the bIueprint specifications that constitute Nature’s demand. More specificaIIy, we shouId consider carefuIIy whether our conception of the arrangement of the muscuIature is suffrcientIy comprehensive to account not onIy for a sphincteric r&e, but as a guardian of the peIvic outIet against the drag of gravity upon the abdominopeIvic viscera. Is it adequate to withstand the assauIts of intra-abdomina1
NEW Szenres VOL. LVIII, No. I
Eaton-ProctoIogic
stress and strain? To answer this question Iet us make brief surveys of the findings of the anatomist and the inferences of the anthropoIogist. The common conception of the arrangement of the anorecta1 muscuIature is that of a series of muscuIar rings surrounding the termination of the intestina1 tube. This concept was the cuImination of anatomic contributions from the time of GaIen4 to the time of HoII.~ GaIen considered the anorectum essentiaIIy as a tube with a muscuIar ring surrounding it. Later investigators, by more precise methods of dissection and scrutiny, found that the “ring” had subdivisions. To these they assigned resounding terminology. FinaIIy, the Ievator ani was found to have a definite r6Ie in sphincteric action. The various components of this structure were recognized as having definite spacia1 reIation to and action upon the terminaI portion of the boweI. But the essentia1 point to remember is that the emphasis has aIways been pIaced upon the anorecta1 muscuIature as being subdivided into a horizonta1 series of rings. This is shown by the usua1 designation of the muscular components from beIow, and proceeding upward, as the subcutaneous, superficiaIis, profundus divisions of the externa1 sphincter with the overIying Ievator with its puborectaIis, pubococcygeus, iIIeococcygeus and ischiococcygeus divisions. Thus, we conceive that sphincteric components are dispersed about the rectum as a series of ascending transverse pIanes. This is a11 partIy true. The anorectal muscuIature is subdivided as enumerated above. Each one of these subdivisions can be recognized by dissection. SeveraI of them are recognized, or shouId be recognized in the majority of recta1 operations. But the description is incompIete because the conception of the arrangement of the anorecta1 muscuIature, as being essentially a “ring series,” is neither pIausibIe from a bioIogic standpoint nor is it true from an anatomic standpoint. In the first pIace, the demand by Nature
PostuIates
American Journsl of Surgery
65
for a strongIy reinforced peIvic outIet cannot be reasonabIy satisfied by such a concept. To satisfy that demand there
FIG. I. StructuraI scheme of anorecta1 muscuIature. The inverted V-shaped sections show how sheaths of conjoined Iongitudinal muscle divide the externa1 sphincter into its components and, thus, form a web. A, B and c, outer, middIe, and inner sheaths, respectively.
must be a structure that binds, connects and reinforces the ring series. To accommodate the stress and strain of gravitationa1 force upon the abdominopeIvic viscera, a strongIy interwoven web of muscuIohbrous tissue is necessary to protect the peIvic outIet. That is to say, there is an extraordinary need for a peIvic diaphragm. While it is true that the tiIt of the peIvis aIIows considerabIe visceral weight to impinge on the posterior surface of the symphysis and ischia1 ramii, and aIso true that the curve of the sacrum and Aexed coccyx serve as supportive factors, these do not suffice to abrogate the need for a muscuIar arrangement that possesses the greatest efhciency of design and pattern. At this point it shouId occur to us that such muscuIar arrangement shouId foIIow the design and pattern of a web. If the muscuIar elements that enter into the composition of the peIvic diaphragm were so arranged as to form a tough, musculofibrous, sIing-Iike, contractiIe, mesh or web we wouId have a structure that could reasonabIy conform to Nature’s specifications for a supportive eIement. Such a web can be formed onIy by the presence of a structure that binds, connects, reinforces
66
American
Journal
of Surgery
Eaton-Proctologic
the ring series and secures firm anchorage to the Iesser peIvic brim. As a matter of fact, this structure exists and this arrangement prevaiIs.
Oc-roBEn, ,942
Postulates
pronograde anthropode couId satisfy his ambition to become a biped, a great muscuIar reinforcement of the peIvic diaphragm was necessary to prevent proIapse of the
FIG. 3. Sketch of ana cana indicating surgica1 landmarks to be recognized by digita paIpation. A, ampuIIa; BY puborectaIis Iedne: c. dentate IeveI Cone-half distance from B to D); D, interna intermuscular groove; E, subcutaneous Iedge; intermuscuIar groove; c, F, external shelf of pubococcygeus. Us
FIG. A SchematIc model of sectcon through anorectal wall indicates paths for extension of infection from branched tubular anal glands (x). I, 2, 3, 4 and 5, Sphincters subcutaneous, superficialis, profundus, puborectaIis, pubococcygeus, respectively. A, FJ and c, outer, middIe and inner sheaths, respectiveIy. Infection passing from glands aIong path c leads to fistuIa; ulcer; aIong IX, to intrasphincteric aIong A, to infralevator abscess and extrasphincteric fistuIa.
The fact that such a .web-Iike arrangement exists not onIy corroborates the natura1 Iaw that structure is subservient to function, but has practical surgica1 sign%cance. However, before we consider the structure that is responsibIe for the web formation we shouId consider how it came about. That the anorecta1 muscuIature is arranged in the form of a web is shown by a brief survey of anthropoIogy. EvoIution has been the primary factor in causing an intricate, %eb Iike arrangement of the anorecta1 muscuIature. As a resuIt of the assumption of the upright posture, there was a strong demand for great reinforcement of the peIvic outIet. In order that the
I
peIvic viscera. Accompanying the shift of the stress of gravity from the ventra1 waI1 (as in the pronograde ape) to that of the perinea1 waI1 (as exemphfied in the chimpanzee), a great modification of structure was demanded in order to serve the new functiona demand resuIting from the assumption of the upright posture. This demand for muscuIar reinforcement was satisfied and suppIied by the tai1 muscles. Since a comparative!y weak sphincter sufficed to serve the pronograde type, whose viscera1 weight was on the ventra1 waI1, the cauda1 muscIes were Ieft free to motivate the tai1. However, with the increased strain on the peIvic outIet brought about by the assumption of the upright posture, additiona protection was needed and suppIied by an anatomic shift of the cauda1 muscIes. l’hus, the base of the tai1 was puIIed forward to become a peIvic shutter. The cauda1 muscIes hypertrophied, became tough and fibrous, and interdigi-
NEW SERIES VOL. LVIII,
No.
I
Eaton-ProctoIogic
tated with the sphincter so as to form a web as the most efficient means for supporting the pelvic viscera. In other words, the dramatic assumption of an upright posture
FIG. 4. Prolapsed hemorrhoids. The “dentate Ievel” (Fig. 3c) wiI1 determine the upper extent of excision.
Postulates
Journal of Surgery
67
raIe, what does it accomphsh? FinaIIy, why is its recognition indispensabIe for the consistent surgica1 reIief of the clinica entities that arise from anal infection?
FIG. 3. AnaI stenosis with uIcer. A portion of the “subcutaneous Iedge” (Fig. 3E) must be excised in addition to the ulcer bearing area.
by Iate anthropoids was accompanied by the marriage of two sets of muscIes (tai1 and sphincter muscIes) whose union was demanded by the need for increased peIvic support.6*7 And thus was formed the ana web. Here, an interesting coroIIary suggests corroboration for this hypothesis : If the anorecta1 muscuIature was derived entireIy from the primitive cIoaca1 sphincter, it wouId be IogicaI to assume that its nerve suppIy wouId be uniform. We wouId expect that the various morphoIogica1 sphincter components wouId have common innervation. However, this is not the case. WhiIe the primitive sphincter derivatives are innervated by the inferior hemorrhoida branch of the interna pudenda1 nerve, the of the sphincter is profundus division innervated by the fourth sacra1 nerve that originaIIy was directed to the cauda1 muscIe. This neuroIogica1 mixture is a strong indication that the anorecta1 muscuIature is derived from the two sources under consideration, nameIy, taiI and sphincter muscIes.8 What is this structure that transforms the “ring series ” into a web? From whence is it derived? In addition to its supportive
American
FIG. 6. Trans-sphincteric f&da. Inflammatory distortion renders “time-honored” Iandmarks useless.
Responding CategoricaIIy, the structure is the conjoined IongitudinaI muscIe described by Levy in Ig36.g It is “conjoined” because it receives muscuIofibrous components from the Ievator, the external IongitudinaI coat of the bowe1 and contiguous eIements of mesotheIia1 origin. It descends, partIy through and partIy from, the Ievator in the form of sheath-Iike skirts that pass centrifugaIIy from the bowe1 waI1 through the sphincter muscIe and thus divides the Iatter into anatomicaIIy distinct components. By virtue of its tough, muscuIofibrous texture and its course, it binds, connects, and reinforces the sphincter components so that the Iatter are interIaced and enmeshed according to the pIan of a web. (Fig. I .) To a11 of this there is definite surgica1 significance. Not onIy does the ana web account for the pathoIytic mechanism by which the cIinica1 entities are engendered, it aIso aids surgica1 orientation by revealing the structura1 scheme which determines the arrangement of the anorecta1 muscuIature. It explains why muscIe spaces are formed and where they are Iocated. It shows the paths by which infection may gain access to these spaces. It expIains why the variety of
68
American Journalof Surgery
Eaton-ProctoIogic
clinica entity depends upon the depth to which an infected ana gIand penetrates the anal web. (Fig. 2.) But, in addition to this
OCTOBBR, rg*2
PostuIates
he wiI1 paIpate the sphincter integrity, which is the Iast puborectaIis ledge, guardian of continence. When desiring to avoid the necessity for a secondary operation for the cure of infralevator abscess, his pIan of treatment wiI1 be influenced by the precise determination of the muscuIar structures invoIved in such a pIan. (Fig. 7.) COMMENT
FIG. 7. Infralevator abscess. When communicating tract lies distal to puborectalis ledge (Fig. 3~) abscess can be cured in one-stage operation by excising necrotic anal lining with abscess.
correIation of structure to pathoIogy, an even greater advantage is afforded to the surgeon. The anal web affords indispensabIe Iandmarks which may guide the surgeon’s procedure for draining the ana infections. These surgica1 Iandmarks are deviations in the morphoIogic contour of the anorectum which represent attachments of the anaI web to the bowe1 waII, skin and surrounding bony structure. (Fig. 3.) These true Iandmarks enabIe the surgeon to identify sphincter components, muscle spaces and space boundaries. The vaIue of the precise orientation is proved by the practica1 apppIication to the cIinica1 entities. Hence, in removing a proIapsed mass of hemorrhoids (Fig. 4), the surgeon will know where to estabIish a “surgica1 dentate Iine ” : nameIy, at the normal dentate IeveI.lO When sphincter components must be divided for the creation of rest and drainage in the treatment of uIcer or fissure, spasm or stenosis (Fig. 5), he wiI1 first define the subcutaneous muscIe by paIpating the externa1 and interna intermuscuIar grooves. When he is in doubt as to whether his pIan for the adequate excision of a fIstuIous tract (Fig. 6) wiI1 jeopardize
AND
SUMMARY
Since Iimited space prevents amplification in regard to the recognition and use of true Iandmarks in the treatment of the various manifestations of ana infection, we mereIy emphasize that the recta1 surgeon cannot receive proper orientation from a few, time-honored, Iandmarks such as HiIton’s “white Iine” and the Iine of ana crypts. The Iocation of the former is usuaIIy misinterpreted because HiIton’s definition is ambiguous; the Iocation of the Iatter varies according to the degree of inflammation present. Both are subject to pathologica distortion. Proper guidance is afforded onIy by paIpating the structura1 contour of the anorectum and interpreting the deviations of contour in the Iight of anatomica concept. When this is done there wiI1 be truth in the we11 known metaphor: “The educated finger is a probe with an eye at its tip.” REFERENCES
GYORGI, ALBERT v. SZENT. Anat. He&e, 409. 1913. 2. TUCKER, C. C. and HELLWIG, C. A. HistopathoIogy of anal ducts. Tr. Am. hoc. Sot., June, 1933. 3. BuIE, I,. A. Practical Proctology, W. B. Saunders Co., 1937. Administrionei. De 4. GALENUS, C. De Anatomicis Ossibus. M. J. Andermaco. 5. HOLL. K. B. Handbucb der Anat. des Menscben. I.
vat: 7, 1897. 6. EI.FTMAN, H. 0. The evoIution of the pelvic Aoor of primates. Am. J. Anat., vol. 51, 1932. 7. PARAMORE. R.
H. Evolution of the oelvic Aoor in non-mammalian vertebrates and pronograde IllZUTlITlak. hICet, pp. 1393-1399, 1457-1467, 1910. 8. THOMPSON, P. On the levator ani or ischio-anal muscIe of unguIates. J. Anat. cv PlI_ysiol., 33: 423-433, 1899. On the arrangement of the fasciae of the peIvis and their reIationship to the levator ani. J. Anat. &‘PhySiO~., 35: 127-141, 19oI. Anorectal muscuIature. Am. J. 9. L.Ev’I’, EDWARD. Surg., November, 1936. IO. EATON, CHEI.SEA. A technique for ana repair. Am. J. Surg., September, 1940.
POSTULATES
FROM AN ANATOMIC
STANDPOINT ARRANGEMENT
OF ANORECTAL SURGICAL
MUSCULATURE
AS USEFUL
LANDMARKS
CHELSEA EATON, M.D. Attending
ProctoIogist,
HighIand and BerkeIey Hospitals
OAKLAND,
CALIFORNIA
A
LTHOUGH anatomy does not change, anatomic concepts may, and, when they do, the surgeon is first to be concerned. Now that recent discovery indicates that the anorecta1 muscuIature is arranged as a web, rather than as a series of muscuIar rings as has been Iong supposed, there are many inferences to be drawn in regard to the surgica1 drainage of ana infection. The soIution of probIems reIevant to the treatment of the cIinica1 entities commonIy termed hemorrhoids, fissure, ulcer, abscess, IistuIa, stricture, etc., demands two things: First, the recognition that these entities are various manifestations of infection of the ana gIands; second, that their development is conditioned by the spacia1 reIationship of these gIands to the surrounding anorecta1 muscuIature with its encIosed tissue spaces. Wh en these entities are Iooked upon as infections and when the arrangement of the surrounding tissues is recognized, appropriate methods of drainage may be instituted in a precise manner. This manner wiI1 be appropriate, precise and, indeed, effective because the operator who possesses this knowIedge is the onIy one who can profit by the guidance of a number of morphoIogica1 deviations of contour of the anorectum that shouId serve as indispensabIe surgica1 Iandmarks. The correIation of these factors of infection and anatomy wiI1 provide such a workabIe concept that the surgeon may make IogicaI deductions as to the appropriate methods of treatment. Although there is a wide recognition of the etioIogic rBIe of the ana gIands in the 64
production of ana infection, and while most practitioners recognize that the above mentioned clinica entities arise from this consource, we may expect unIimited troversy in this regard. Here, we are chieffy concerned with showing how these gIands tit into the anatomic scheme when pathoIogic changes occur and demand repair. However, we may point out the fact that, starting with Morgagni, a succession of investigators have incriminated these gIands as the provocative agents for the cIinica1 entities.ls2p3 Further ampIification of this factor of infection must be deferred unti1 we consider the arrangement of the anorecta1 muscuIature, the spaces in which these gIands are situated and the paths to which their infection may gain access. In order to gain a conception of the arrangement of the anorecta1 muscuIature, we must first examine the anatomic contributions that form our Iegacy from the we must make certain past; secondIy, deductions from that bioIogic Iaw which states that structure tends to adapt itseIf to function. In other words, we shouId attempt to corroborate and, if possibIe, harmonize the arbitrary, uncorreIated contributions of supposed anatomic facts with the bIueprint specifications that constitute Nature’s demand. More specificaIIy, we shouId consider carefuIIy whether our conception of the arrangement of the muscuIature is suffrcientIy comprehensive to account not onIy for a sphincteric r&e, but as a guardian of the peIvic outIet against the drag of gravity upon the abdominopeIvic viscera. Is it adequate to withstand the assauIts of intra-abdomina1
NEW Szenres VOL. LVIII, No. I
Eaton-ProctoIogic
stress and strain? To answer this question Iet us make brief surveys of the findings of the anatomist and the inferences of the anthropoIogist. The common conception of the arrangement of the anorecta1 muscuIature is that of a series of muscuIar rings surrounding the termination of the intestina1 tube. This concept was the cuImination of anatomic contributions from the time of GaIen4 to the time of HoII.~ GaIen considered the anorectum essentiaIIy as a tube with a muscuIar ring surrounding it. Later investigators, by more precise methods of dissection and scrutiny, found that the “ring” had subdivisions. To these they assigned resounding terminology. FinaIIy, the Ievator ani was found to have a definite r6Ie in sphincteric action. The various components of this structure were recognized as having definite spacia1 reIation to and action upon the terminaI portion of the boweI. But the essentia1 point to remember is that the emphasis has aIways been pIaced upon the anorecta1 muscuIature as being subdivided into a horizonta1 series of rings. This is shown by the usua1 designation of the muscular components from beIow, and proceeding upward, as the subcutaneous, superficiaIis, profundus divisions of the externa1 sphincter with the overIying Ievator with its puborectaIis, pubococcygeus, iIIeococcygeus and ischiococcygeus divisions. Thus, we conceive that sphincteric components are dispersed about the rectum as a series of ascending transverse pIanes. This is a11 partIy true. The anorectal muscuIature is subdivided as enumerated above. Each one of these subdivisions can be recognized by dissection. SeveraI of them are recognized, or shouId be recognized in the majority of recta1 operations. But the description is incompIete because the conception of the arrangement of the anorecta1 muscuIature, as being essentially a “ring series,” is neither pIausibIe from a bioIogic standpoint nor is it true from an anatomic standpoint. In the first pIace, the demand by Nature
PostuIates
American Journsl of Surgery
65
for a strongIy reinforced peIvic outIet cannot be reasonabIy satisfied by such a concept. To satisfy that demand there
FIG. I. StructuraI scheme of anorecta1 muscuIature. The inverted V-shaped sections show how sheaths of conjoined Iongitudinal muscle divide the externa1 sphincter into its components and, thus, form a web. A, B and c, outer, middIe, and inner sheaths, respectively.
must be a structure that binds, connects and reinforces the ring series. To accommodate the stress and strain of gravitationa1 force upon the abdominopeIvic viscera, a strongIy interwoven web of muscuIohbrous tissue is necessary to protect the peIvic outIet. That is to say, there is an extraordinary need for a peIvic diaphragm. While it is true that the tiIt of the peIvis aIIows considerabIe visceral weight to impinge on the posterior surface of the symphysis and ischia1 ramii, and aIso true that the curve of the sacrum and Aexed coccyx serve as supportive factors, these do not suffice to abrogate the need for a muscuIar arrangement that possesses the greatest efhciency of design and pattern. At this point it shouId occur to us that such muscuIar arrangement shouId foIIow the design and pattern of a web. If the muscuIar elements that enter into the composition of the peIvic diaphragm were so arranged as to form a tough, musculofibrous, sIing-Iike, contractiIe, mesh or web we wouId have a structure that could reasonabIy conform to Nature’s specifications for a supportive eIement. Such a web can be formed onIy by the presence of a structure that binds, connects, reinforces
66
American
Journal
of Surgery
Eaton-Proctologic
the ring series and secures firm anchorage to the Iesser peIvic brim. As a matter of fact, this structure exists and this arrangement prevaiIs.
Oc-roBEn, ,942
Postulates
pronograde anthropode couId satisfy his ambition to become a biped, a great muscuIar reinforcement of the peIvic diaphragm was necessary to prevent proIapse of the
FIG. 3. Sketch of ana cana indicating surgica1 landmarks to be recognized by digita paIpation. A, ampuIIa; BY puborectaIis Iedne: c. dentate IeveI Cone-half distance from B to D); D, interna intermuscular groove; E, subcutaneous Iedge; intermuscuIar groove; c, F, external shelf of pubococcygeus. Us
FIG. A SchematIc model of sectcon through anorectal wall indicates paths for extension of infection from branched tubular anal glands (x). I, 2, 3, 4 and 5, Sphincters subcutaneous, superficialis, profundus, puborectaIis, pubococcygeus, respectively. A, FJ and c, outer, middIe and inner sheaths, respectiveIy. Infection passing from glands aIong path c leads to fistuIa; ulcer; aIong IX, to intrasphincteric aIong A, to infralevator abscess and extrasphincteric fistuIa.
The fact that such a .web-Iike arrangement exists not onIy corroborates the natura1 Iaw that structure is subservient to function, but has practical surgica1 sign%cance. However, before we consider the structure that is responsibIe for the web formation we shouId consider how it came about. That the anorecta1 muscuIature is arranged in the form of a web is shown by a brief survey of anthropoIogy. EvoIution has been the primary factor in causing an intricate, %eb Iike arrangement of the anorecta1 muscuIature. As a resuIt of the assumption of the upright posture, there was a strong demand for great reinforcement of the peIvic outIet. In order that the
I
peIvic viscera. Accompanying the shift of the stress of gravity from the ventra1 waI1 (as in the pronograde ape) to that of the perinea1 waI1 (as exemphfied in the chimpanzee), a great modification of structure was demanded in order to serve the new functiona demand resuIting from the assumption of the upright posture. This demand for muscuIar reinforcement was satisfied and suppIied by the tai1 muscles. Since a comparative!y weak sphincter sufficed to serve the pronograde type, whose viscera1 weight was on the ventra1 waI1, the cauda1 muscIes were Ieft free to motivate the tai1. However, with the increased strain on the peIvic outIet brought about by the assumption of the upright posture, additiona protection was needed and suppIied by an anatomic shift of the cauda1 muscIes. l’hus, the base of the tai1 was puIIed forward to become a peIvic shutter. The cauda1 muscIes hypertrophied, became tough and fibrous, and interdigi-
NEW SERIES VOL. LVIII,
No.
I
Eaton-ProctoIogic
tated with the sphincter so as to form a web as the most efficient means for supporting the pelvic viscera. In other words, the dramatic assumption of an upright posture
FIG. 4. Prolapsed hemorrhoids. The “dentate Ievel” (Fig. 3c) wiI1 determine the upper extent of excision.
Postulates
Journal of Surgery
67
raIe, what does it accomphsh? FinaIIy, why is its recognition indispensabIe for the consistent surgica1 reIief of the clinica entities that arise from anal infection?
FIG. 3. AnaI stenosis with uIcer. A portion of the “subcutaneous Iedge” (Fig. 3E) must be excised in addition to the ulcer bearing area.
by Iate anthropoids was accompanied by the marriage of two sets of muscIes (tai1 and sphincter muscIes) whose union was demanded by the need for increased peIvic support.6*7 And thus was formed the ana web. Here, an interesting coroIIary suggests corroboration for this hypothesis : If the anorecta1 muscuIature was derived entireIy from the primitive cIoaca1 sphincter, it wouId be IogicaI to assume that its nerve suppIy wouId be uniform. We wouId expect that the various morphoIogica1 sphincter components wouId have common innervation. However, this is not the case. WhiIe the primitive sphincter derivatives are innervated by the inferior hemorrhoida branch of the interna pudenda1 nerve, the of the sphincter is profundus division innervated by the fourth sacra1 nerve that originaIIy was directed to the cauda1 muscIe. This neuroIogica1 mixture is a strong indication that the anorecta1 muscuIature is derived from the two sources under consideration, nameIy, taiI and sphincter muscIes.8 What is this structure that transforms the “ring series ” into a web? From whence is it derived? In addition to its supportive
American
FIG. 6. Trans-sphincteric f&da. Inflammatory distortion renders “time-honored” Iandmarks useless.
Responding CategoricaIIy, the structure is the conjoined IongitudinaI muscIe described by Levy in Ig36.g It is “conjoined” because it receives muscuIofibrous components from the Ievator, the external IongitudinaI coat of the bowe1 and contiguous eIements of mesotheIia1 origin. It descends, partIy through and partIy from, the Ievator in the form of sheath-Iike skirts that pass centrifugaIIy from the bowe1 waI1 through the sphincter muscIe and thus divides the Iatter into anatomicaIIy distinct components. By virtue of its tough, muscuIofibrous texture and its course, it binds, connects, and reinforces the sphincter components so that the Iatter are interIaced and enmeshed according to the pIan of a web. (Fig. I .) To a11 of this there is definite surgica1 significance. Not onIy does the ana web account for the pathoIytic mechanism by which the cIinica1 entities are engendered, it aIso aids surgica1 orientation by revealing the structura1 scheme which determines the arrangement of the anorecta1 muscuIature. It explains why muscIe spaces are formed and where they are Iocated. It shows the paths by which infection may gain access to these spaces. It expIains why the variety of
68
American Journalof Surgery
Eaton-ProctoIogic
clinica entity depends upon the depth to which an infected ana gIand penetrates the anal web. (Fig. 2.) But, in addition to this
OCTOBBR, rg*2
PostuIates
he wiI1 paIpate the sphincter integrity, which is the Iast puborectaIis ledge, guardian of continence. When desiring to avoid the necessity for a secondary operation for the cure of infralevator abscess, his pIan of treatment wiI1 be influenced by the precise determination of the muscuIar structures invoIved in such a pIan. (Fig. 7.) COMMENT
FIG. 7. Infralevator abscess. When communicating tract lies distal to puborectalis ledge (Fig. 3~) abscess can be cured in one-stage operation by excising necrotic anal lining with abscess.
correIation of structure to pathoIogy, an even greater advantage is afforded to the surgeon. The anal web affords indispensabIe Iandmarks which may guide the surgeon’s procedure for draining the ana infections. These surgica1 Iandmarks are deviations in the morphoIogic contour of the anorectum which represent attachments of the anaI web to the bowe1 waII, skin and surrounding bony structure. (Fig. 3.) These true Iandmarks enabIe the surgeon to identify sphincter components, muscle spaces and space boundaries. The vaIue of the precise orientation is proved by the practica1 apppIication to the cIinica1 entities. Hence, in removing a proIapsed mass of hemorrhoids (Fig. 4), the surgeon will know where to estabIish a “surgica1 dentate Iine ” : nameIy, at the normal dentate IeveI.lO When sphincter components must be divided for the creation of rest and drainage in the treatment of uIcer or fissure, spasm or stenosis (Fig. 5), he wiI1 first define the subcutaneous muscIe by paIpating the externa1 and interna intermuscuIar grooves. When he is in doubt as to whether his pIan for the adequate excision of a fIstuIous tract (Fig. 6) wiI1 jeopardize
AND
SUMMARY
Since Iimited space prevents amplification in regard to the recognition and use of true Iandmarks in the treatment of the various manifestations of ana infection, we mereIy emphasize that the recta1 surgeon cannot receive proper orientation from a few, time-honored, Iandmarks such as HiIton’s “white Iine” and the Iine of ana crypts. The Iocation of the former is usuaIIy misinterpreted because HiIton’s definition is ambiguous; the Iocation of the Iatter varies according to the degree of inflammation present. Both are subject to pathologica distortion. Proper guidance is afforded onIy by paIpating the structura1 contour of the anorectum and interpreting the deviations of contour in the Iight of anatomica concept. When this is done there wiI1 be truth in the we11 known metaphor: “The educated finger is a probe with an eye at its tip.” REFERENCES
GYORGI, ALBERT v. SZENT. Anat. He&e, 409. 1913. 2. TUCKER, C. C. and HELLWIG, C. A. HistopathoIogy of anal ducts. Tr. Am. hoc. Sot., June, 1933. 3. BuIE, I,. A. Practical Proctology, W. B. Saunders Co., 1937. Administrionei. De 4. GALENUS, C. De Anatomicis Ossibus. M. J. Andermaco. 5. HOLL. K. B. Handbucb der Anat. des Menscben. I.
vat: 7, 1897. 6. EI.FTMAN, H. 0. The evoIution of the pelvic Aoor of primates. Am. J. Anat., vol. 51, 1932. 7. PARAMORE. R.
H. Evolution of the oelvic Aoor in non-mammalian vertebrates and pronograde IllZUTlITlak. hICet, pp. 1393-1399, 1457-1467, 1910. 8. THOMPSON, P. On the levator ani or ischio-anal muscIe of unguIates. J. Anat. cv PlI_ysiol., 33: 423-433, 1899. On the arrangement of the fasciae of the peIvis and their reIationship to the levator ani. J. Anat. &‘PhySiO~., 35: 127-141, 19oI. Anorectal muscuIature. Am. J. 9. L.Ev’I’, EDWARD. Surg., November, 1936. IO. EATON, CHEI.SEA. A technique for ana repair. Am. J. Surg., September, 1940.