THE TONSILS Cross-section of human tonsil, age eleven years, dissected out in capsule. X 10. This tonsil was moderately hypertrophied, with crypts greatly dilated and filled with detritus. It represents a condition found in a large percentage of the hypertrophied tonsils of childhood. A, Crypts, very irregular and dilated; B, Plica triangularis; C, Anterior fossa; D, Lymphoid follicles outside capsule; E, Surface epithelium; F, Tunica propria of surface mucosa; G, Mucous glands; H, Muscle fibers of capsule; K, Capsule; E, Trabecula; M, Blood vessel; N, Lym- phoid follicle with germinal center; P, Posterior fossa. THE TONSILS FAUCIAL, LINGUAL, ANI) PHARYNGEAL WITH SOME ACCOUNT OF THE POSTERIOR AND LATERAL PHARYNGEAL NODULES BY HARRY A. BARNES, M.D. INSTRUCTOR IN LARYNGOLOGY, HARVARD MEDICAL SCHOOL; LARYNGOLOGIST, MAS- SACHUSETTS CHARITABLE EYE AND EAR INFIRMARY; LARYNGOLOGIST, MASSA- CHUSETTS GENERAL HOSPITAL; MEMBER NEW ENGLAND LARYNGOLOGICAL AND OTOLOGICAL SOCIETY; MEMBER AMERICAN LARYNGOLOGICAL, RIIINOLOGICAL AND OTOLOGICAL SOCIETY; MEMBER AMERICAN LARYNGOLOGICAL ASSOCIATION ILLUSTRATED SECOND EDITION ST. LOUIS C. V. MOSBY COMPANY 1923 Copyright, 1914, 1923, by C. V. Mosby Company (All rights reserved.) Printed in U. S. A. Press of C. V. Mosby Company St. Louis TO WILLIAM THOMAS COUNCILMAN, A.M., M.D., LL.D., Shattuck Professor of Pathological Anatomy, Medical School of Harvard University, Who Initiated Me into the Study of the Lymphoid Tissues THIS BOOK IS RESPECTFULLY INSCRIBED. PREFACE TO THE SECOND EDITION Since the first edition of this book was published nine years ago there has been a tendency towards greater uni- formity of opinion on the tonsils, and the operations for their removal have been improved and more or less stand- ardized. Several new operations have appeared, notably the Capsule Splitting Operation and those based on this principle so well enunciated by Makuen in 1915. Time has given us material for a sounder judgment on the relations of tin1 tonsils to focal infections. Radiation as a means of producing atrophy of the lymphoid tissues has appeared and is even yet on trial. This edition of The Tonsils re- flects all of these changes. Much that is new has been added to the sections on operations, their sequelae and complications. The newer operations, as the old, are de- scribed at length, and the technic of local anesthesia has received special attention. The chapter on focal infections has been practically rewritten. The section on the x-ray and radium treatment of tonsillar hypertrophy is, of course, new. A number of plates illustrative of operative technic have been added. Harry A. Barnes. Boston, March 3, 1923. PREFACE TO FIRST EDITION During tlie past few years the tonsils have held such a prominent place in the periodical medical press, as seem- ingly to make unnecessary a hook devoted to them. Yet this mass of literature is not entirely satisfactory, both on account of its bulk and because of the wide divergence of opinion on certain phases of the subject. This book lays no claim to having settled any of the mooted questions. It is an attempt to put into concise form the facts concern- ing the lymphoid tissues of the throat, and to make these facts the basis of any theories advanced. The more strictly scientific parts have been written with a view to emphasizing their practical application to clinical work. I hope they have lost nothing of their scientific value on that account. The illustrations in the book are all original. Many of the histological plates are from photo-micrographs; others are from drawings by Miss Etta R. Piotti, and are faith- ful representations of typical microscopic fields. The drawings illustrating operative technic are by Miss D. P. Blair, and are the result of personal observation in the operating room. I have to thank both Miss Piotti and Miss Blair for their excellent work. My thanks are also due Dr. J. L. Goodale for suggesting my name to the pub- lishers, as one likely to have the material for a book on the tonsils; Dr. Charles S. Minot and Dr. John Warren of the Harvard Medical School for embryological material; and Dr. A. Coolidge, Jr., Chief of the Laryngological Staff, Massachusetts General Hospital, for kindly reading parts of the book in manuscript. Harry A. Barnes. Boston, July, 1914. CONTENTS CHAPTER I PAGE The General Nature op Lymphoid Tissue 17 CHAPTER II The Development of the Tonsil 22 The Development of the Crypts1, 28; The Lymphoid Tissue, 25; The Root of the Tonsil, 25; The Development of the Fossae, 25; The Development of the Capsule, 27; Histogenesis of the Tonsil, 28. CHAPTER III The Anatomy and Histology op the Tonsils 30 The Anatomy and Histology of the Faucial Tonsil, 30; The Crypts, 30; The Sinus Tonsillaris, 32; The Plica;, 32; The Root of the Tonsil, 34; The Superior or Supratonsillar Fossa, 35; The Anterior Fossa, 35; A Posterior Fossa, 36; The Capsule, 36; Types of Tonsil, 37; The Blood Supply of the Tonsils, 38; The Lymphatics of the Tonsils, 39; The Nerve Supply of the Tonsils, 43; The Relations of the Tonsil, 43; The Normal Histology of the Tonsil, 45; The Capsule, 46; The Crypts, 46; The Epithelium, 48; The Hypertrophied Tonsil, 52; What Constitutes Hypertrophy of the Tonsils, 53; The Causes of Hypertrophy, 56; The Atrophic or Re- gressive Tonsil, 57; The Anatomy and Histology of the Lingual Tonsil and the Infratonsillar Nodules, 60; The Anatomy and Histology of the Pharyngeal Tonsil, 62; The Lymphoid Tissue of the Posterior Wall and Lateral Folds of the Pharynx, 65. CHAPTER IV The Function op the Tonsils 68 The Hemopoietic Theory, 68; The Internal Secretion Theory, 69; The Protection Theory, 70; The Eliminating Theory, 73; The Immunity Theory, 73. CHAPTER V The General Pathology and Bacteriology op the Tonsils.—Their Relation to Systemic Infections 76 The Bacteriology of the Crypts, 79; The Relation of the Tonsils to Systemic Infections. Focal Infections, 83; Acute Rheumatic 13 14 CONTENTS PAGE Fever, 86; Infectious Arthritis, 87; Endocarditis, 88; Chorea, 89; Nephritis, 89; Rheumatoid Arthritis, Arthritis Deformans, 90; Myositis (Myalgia), Neuritis, Bursitis, Periostitis, Osteomyelitis, 91; Tuberculosis, 91; The Relation of Age to Tonsillar Infection, 92. CHAPTER VI Diseases oe the Tonsils 94 Acute Tonsillitis, 94; Acute Follicular Tonsillitis, 94; Septic Sore Throat, 99; Acute Suppurative Tonsillitis, 103; Peritonsillar Ab- scess (Quinsy Sore Throat), 104; Vincent’s Angina, 112; Chronic Tonsillitis, 118; Chronic Suppurative Tonsillitis, 119; Cyst of the Tonsil, 120; Calculus of the Tonsil, 120; Hyperkeratosis Tonsillaris, 121; Diphtheria, 126; Tuberculosis of the Tonsils, 126; Syphilis of the Tonsils, 131; Diseases of the Lingual Tonsil, 135; Hypertrophy, 135; Acute Lingual Tonsillitis, 135; Chronic Retention, 135; Abscess Formation, 135; An Accessory Thyroid Gland., 136. CHAPTER VII Diseases of the Pharyngeal Tonsil (Adenoids) 138 Thornwaklt’s Disease, 147. CHAPTER VIII Neoplasms of the Tonsils 14S Benign Neoplasms, 148; Malignant Neoplasms, 149; Treatment of Malignant Tumors, 151. CHAPTER IX Surgery of the Tonsils 153 The Choice of Operations, 153; Tonsillectomy, 155; Indications, 155; Anesthesia, 158; Local Anesthesia, 159; General Anesthesia, 162; The Preparation of the Patient, 163; The Position of the Patient, 164; The Operations, 164; Treatment of the Operative Wound, 189; Postoperative Treatment, 187. CHAPTER X Complications and Sequelae of Operations on tile Tonsils . . . 189 Hemorrhage, 189; Septic Infection, 199; Deep Abscess of the Neck, 201; Pulmonary Abscess, 202; Postoperative Diphtheria, 204; Diphtheria Carriers, 205; Postoperative Deformities, 205; The Effects of Tonsillectomy on the Singing Voice, 206; The X-ray and Radium Treatment of Tonsillar Hypertrophy, 207. ILLUSTRATIONS Cross Section of Human Tonsil Frontispiece FIG. PAGE 1. Section of the faucial tonsil 18 2. Section of lymphoid tissue of the tonsil 19 3. Faucial tonsil, human embryo of seven months, showing the crypts in different stages of development 24 4. Faucial tonsil, human embryo of seven months, showing the forma- tion of a branching crypt 24 5. Diagrams illustrating the development of the tonsil .... 29 6. Tonsil of childhood. The relation of the capsule to the plica triangularis 31 7. Tonsil of childhood. The development of the attached plica . . 33 8. Tonsil of childhood. The relation of the capsule to the supraton- sillar fossa 30 9. Diagram showing the upper cervical lymphatic glands .... 40 10. Cross section of the human tonsil of six months 47 11. Cross section of the human tonsil of eleven months .... 48 12. Small field from Fig. 10, showing the follicles distinctly ... 49 13. Field from Fig. 10, showing two crypts 50 14. Cryptic epithelium of the tonsil of the child under high magnification 51 15. Hypertrophy of the tonsil of the child 53 16. Fibrous hypertrophy of the adult tonsil 54 17. The atrophic tonsil (twenty years) 58 18. The regressive tonsil of the adult (fifty-three years) .... 59 19. Vertical section of the lingual tonsil, from a child of twelve years 61 20. Vertical section of the pharyngeal tonsil (eleven years) ... 63 21. Epithelium of a crypt of the pharyngeal tonsil 64 22. The organisms of Vincent’s angina 114 23. Hyperkeratosis of the tonsil 123 24. Hyperkeratosis of the tonsil, showing the compact character of the cryptic epithelium 125 25. Latent tuberculosis of the tonsil 127 26. Field from Fig. 24, showing the histology of the tubercle . . . 128 27. Active tuberculosis of the tonsil,, showing the tubercle bacilli . . 129 28. The La Force adenotome, the Schuetz adenotome and the Boeck- mann curette 145 29. Boston tonsil syringe 161 15 16 ILLUSTRATIONS PAGE 30. The right-angle tonsil knife, the author’s tonsil grasping forceps, and the peritonsillar knife for tonsil dissection 166 31. The dissection of the tonsil. First step 168 32. The dissection of the tonsil. Second step 169 33. The Farlow tonsil snare 170 34. The dissection of the tonsil. Third and fourth steps .... 171 35. Sorensen section machine 172 36. The dissection of the tonsil. The sinus tonsillaris after the tonsil has been removed 173 37. The Sluder Guillotine (Sauer’s modification) 176 38. The Beck-Schenk snare 179 39. La Force guillotine 183 40. Braun snaretome 184 41. Schoemaker’s artery forceps 194 42. Diagrams showing the correct and incorrect position of sutures . 195 43. Mosher’s aneurism needle and suture carrier for suturing the faucial pillars 196 44. Suturing the faucial pillars 197 45. Michel’s metal clamps' for the control of tonsillar hemorrhage being placed in position 198 THE TONSILS CHAPTER I THE GENERAL NATURE OF LYMPHOID TISSUE Before describing tlie anatomy of the tonsil in detail, it will be well to explain briefly the general character of lymphoid tissue, of which it is composed. Lymphoid tissue in its simplest form may be defined as a reticular connec- tive tissue with a greater or less number of lymphocytes in its mesh. The lymphocytes cannot be distinguished from those of the blood. They may be scattered diffusely in the reticulum or they may be closely packed within a circum- scribed area, and we have accordingly diffuse lymphoid tissue and circumscribed lymphoid tissue. As there is no sharp distinction between the two, I shall in the following- pages apply the term diffuse lymphoid tissue to both indis- criminately, meaning by that, lymphoid tissue with an indefinitely disposed reticulum, in contradistinction to the lymphoid follicle, in which the reticulum assumes a definite form. Lymphoid tissue is widely distributed in the body. It is found in the lymphatic glands, in the Malpighian cor- puscles of the spleen, and in the mucous membranes of the alimentary and respiratory tracts, where it occurs both in the widely diffuse form and in the form of nodules, the most prominent of which are the solitary follicles and Beyer’s patches of the intestinal mucosa, and the tonsillar ring of the fauces and pharynx. The mucosa of the vermi- form appendix contains a large number of lymphoid follicles. If a slide containing a cross section of one of the lym- 17 18 THE TONSILS plioid nodules of the pharynx, stained with eosine and methylene blue, is held to the light, it shows an almost uni- formly stained light blue surface. In close relation to the epithelium, and at more or less regular intervals, are round Fig. 1.—Section of the faucial tonsil. Two follicles are seen in the diffuse lymphoid tissue on either side of the crypt. or oval areas just large enough to be seen without the aid of a glass, which are differentiated from the surrounding tissue. Each shows a circle of deep blue which is usually considerably thickened on the side nearest the epithelium, giving a seal ring effect, while within the circle is a center of a pale rose color. These are the lymphoid follicles. Examined under the low power of the microscope, the general surface shows a tine and indefinitely arranged reticulum, packed with lymphocytes and partially obscured by them. Other cells are jiresent but are comparatively GENERAL NATURE OF LYMPHOID TISSUE 19 Fig. 2.—Section of lymphoid tissue of the tonsil. High power. The darkly shaded oval ring of lymphocytes with the lighter center (the germinal center) occupying the greater part of the section is the follicle, around which is the diffuse lymphoid tissue. A, fibrous trabecula; B, plasma cells near the trabecula; C, lymphoblasts with mitotic figures of the nuclei; D, endothelial cells of the reticulum; E, polynuclear leucocyte; F, plasma cells near the epithelium; G, epithelium of the crypt in the usual fragmented state of this tissue during childhood. inconspicuous. The blue ring at the periphery of the follicle shows a reticulum arranged in definite concentric circles round the pale center; its mesh is even more 20 THE TONSILS crowded with lymphocytes than the adjacent diffuse tissue. The center shows an extremely delicate and indefinite retic- ulum with a loose aggregation of cells which take the nuclear stain but faintly or are acidophylic in character. Examined under the high power the cells of the center appear at first glance to be of many different kinds. On closer examination, however, it will lie seen that there are but two types of cells. The more numerous are cells larger than the lymphocyte, with faintly stained nucleus and in- definite cell outline. The nuclei often show mitotic figures. These cells are the lymphoblasts or “mother cells.” Be- tween them and the lymphocyte many intermediate forms are found in the centers, the lymphocytes becoming more predominant as the periphery is approached. The second type of cell in the centers has an acidophylic protoplasm and a large, pale, vesicular nucleus. This is the endothelial cell of the reticulum. It is very phagocytic and often shows nuclear fragments in its protoplasm. Both the lympho- blasts and the endothelial cells are found in the diffuse tis- sue outside of the follicles, but their numbers are com- paratively small and they are masked by the large numbers of lymphocytes. Polymorphonuclear leucocytes are pres- ent in small numbers in the diffuse tissue, their proportion increasing somewhat near the epithelial surface. Plasma cells1 are found in considerable numbers immediately be- low the cryptic epithelium, in the vicinity of the fibrous framework of the node and around the blood vessels. In the mucous membranes the lymphoid tissue is devel- oped in the fibrous layer (the tunica propria). It may be diffuse, in which case it is microscopic in character; or a single follicle may appear, usually embedded in a small amount of diffuse tissue (the solitary follicles of the intes- tinal mucosa). Several closely related follicles with diffuse 1These cells are modified lymphocytes with excentric nucleus and an increase in cytoplasm, which is basophylic in character. They may be multinuclear. They are characteristic of chronic inflammatory lesions. GENERAL NATURE OE LYMPHOID TISSUE 21 tissue between them, form a patch of considerable size, (Peyer’s patches). The area of such a patch is limited only by the number of associated follicles; but as the fol- licles are not superimposed but simply lie side by side, it will be seen that the thickness of a nodule in a simple mucosa is limited to the thickness of a single follicle plus a slight amount of diffuse tissue. Whenever, therefore, lymphoid nodules of any considerable bulk are developed in the mucous membranes within a small area, the mucosa will be found to be folded or invaginated in the form of pits or crypts, thus creating a large surface of mucosa within a contracted space, much as the radiating surface of a heat- ing apparatus is increased many times by the use of pipes in the place of a single large chamber. In this way large masses of lymphoid tissue are developed in the mucous membranes within small areas. Their size depends on the number and size of the folds or crypts of the mucosa. Their unit is the crypt, surrounded by a shallow layer of lymphoid tissue developed in the more superficial layers of the propria, which in turn is enveloped by the deeper fibers of the propria. The small nodules on the posterior pharyn- geal wall usually consist of a single unit and the crypt is very small and shallow. The larger of these, however, may be composed of several units. The faucial tonsil is the result of the fusing of many units and the crypts are very extensive and complicated. The lingual and pharyngeal tonsils result from a combination of folding and pitting. In the former the folding is not deep; in the latter it is very extensive. CHAPTER II THE DEVELOPMENT OP THE TONSIL The tonsil is developed in a primary tonsillar fossa, the sinus tonsillaris (His), which is formed by the dorsal elongation of the second pharyngeal poncli, and becomes sharply marked at the beginning of the third month of fetal life by the development of the palatal arches. At this time the sinns is narrowed by a small elevation, the tonsillar tubercle (Hammar),1 which lies posterior to the anterior arch. The tubercle soon flattens and becomes undermined posteriorly, so as to form a thin fold, the plica triangularis (Iiis), which extends backward from the faucial surface of the anterior arch without line of demarcation between the two, and converts the sinus into a pocket of which it forms an incomplete inner wall. The plica is attached above to the superior part of the posterior arch, anteriorly to the anterior arch, and below to the pharyngeal wall just above the base of the tongue. Between the free posterior border of the plica and the posterior arch is a narrow opening which connects the sinus with the faucial cavity. The sinus is in shape a right angle triangle, owing to the fact that the posterior arch extends nearly horizontally backward. It retains this shape until some time after birth, when the posterior arch is gradually drawn into a nearly vertical position by the forward growth of the tongue. As late as the end of the second year it may still have a decided back- ward inclination.2 About the middle of the third month another fold ap- pears, the intratonsillar fold (Hammar), which springs from the outer wall of the sinus and extends from about 'Hamniar, J. A.: Studien ikber die Entwicklung des Vorderdarms, etc., Arch. f. mikr. Anat., 1903, lxi. 2Mosher, H. P.: The Tonsil at Birth, Laryngoscope, November, 1903. 22 DEVELOPMENT OF THE TONSIL 23 the middle of the plica upward and backward to the pos- terior arch. It divides the sinus into two fossae, a superior and an inferior, which become the points of development of separate tonsillar lobes. Of these fossae the superior is the larger and deeper. It is bounded on all sides sharply; above and in front by the plica, which converts it into a deep pocket, behind by the posterior arch, and below by the intratonsillar fold. The inferior fossa is shallow and is sharply marked only in front and below, where the plica forms a pocket of varying extent. Elsewhere its lateral wall merges insensibly with the lateral pharyngeal wall. In the later months of fetal life the posterior border of both fossae may become more sharply marked by the de- velopment of another fold, the plica retrotonsillaris, which extends forward from the anterior edge of the posterior arch. It is continuous above and below with the plica tri- angularis, so that the combined folds extend completely round the sinus. This fold is inconstant. The Development of the Crypts.—At the end of the fourth month of fetal life there begin to be developed in the floor and outer wall of each fossa solid epithelial sprouts which grow outward into the surrounding fibrous tissue of the mucosa. They differ in shape and size, some being round or oval and without marked change in their contour throughout their length. Others present branched pro- tuberances of various length and size. These solid sprouts do not all appear at once, but, according to Stohr,3 are de- veloped from time to time, not only during fetal life but throughout the first year of infancy. I have found them in the tonsils of infants up to the eleventh month. Soon after their appearance they become hollow through the degenera- tion of their central cells, which form loose horny plugs and are gradually expelled into the faucial cavity. The result is a series of blind epithelial pits, which at first are 3Stohr, P.: Die Entwicklung des adenoiden Gewebes, usw., Festschr. z. funfzigyahr- igen Doktar jubilaum von Nageli und Kolliker, 1891. (Author’s abstract in Anat. Anz., 1891-1892, iv. 24 THE TONSILS Fig. 3.—Faucial tonsil, human embryo of seven months, showing the crypts in different stages of development. The plica triangularis is in the lower left quadrant. Fig. 4. Faucial tonsil, human embryo of seven months, showing the formation of a branching crypt. quite open, retaining the contour of the original solid buds. A\ ith the development of the lymphoid tissue around them their walls become compressed, so that they assume more DEVELOPMENT OE THE TONSIL 25 and more the aspect of epithelial slits as we find them in the mature tonsil. The Lymphoid Tissue.—Around these epithelial out- growths lymphoid tissue is developed in the more super- ficial fibers of the tunica propria of the mucosa. It is at first of the diffuse variety, and, according to Stohr, remains so until about the fourth month of infancy. Hammar, how- ever, found secondary nodules (follicles), in the later months of fetal life (embryo of 245 mm.), and Griinwald4 reports finding them in embryos of seven and eight months. I found none in the tonsils of three fetuses of seven, seven and eight months respectively which were sectioned seri- ally; and in five infant tonsils of six, seven, nine, ten and eleven months, follicles were plainly marked only in the last three. In the first two only faint suggestions of follicles could be seen. The Root of the Tonsil.—That part of the surface of the outer wall of the sinus which is concerned in the develop- ment of the epithelial buds constitutes the root or point of attachment of the tonsil to the pharyngeal wall. It varies in extent, and this variation has an important bearing on the character of the fully developed tonsil and also on the depth of the fossse which surround it. This will be dis- cussed in the section on anatomy and histology. With the increase in the number of epithelial buds and in the lymphoid tissue around them, the two tonsillar lobes expand and eventually fuse at the line of the intratonsillar fold, which disappears as such, leaving either a crescentic epithelial cleft of varying depth between the two lobes, or more often only a fibrous trabecula, which extends between the lobes to the fibrous mucosa on the outer side of the tonsil. The line of demarcation between the lobes is usually plainly marked in the fully developed tonsil. The Development of the Fossse.—The now united tonsil- 4Griinwald, L.: Ein Beitrag zur Entstehung und Bedeutung der Gaumenmandeln, Anat. Anz., 1910, xxxvii. 26 THE TONSILS lar mass presses more and more closely upon the walls of the sinus, which surround it much as the calyx surrounds the growing bud. It finally bursts through the faucial opening of the sinus; and the jhica, partly because it may be pushed forward by the growing tonsil, and partly be- cause of the forward growth of the tongue, may undergo a greater or less reduction at its inferior insertion. If no reduction takes place, the tonsil is suspended as by a sling by the plica and a deep fossa exists between the two an- teriorly and interiorly. Between this condition and one in which only a slight fringe of plica remains anteriorly, all gradations may be seen. In the latter condition the inferior fossa is wanting and the inferior lobe of the tonsil lies naked in the fauces, in close relation with the base of the tongue and the lingual tonsil. The anterior fossa is shal- low. If a plica retrotonsillaris is present there is a pos- terior fossa between it and the tonsil, which is continuous with the inferior fossa if one exist. The superior lobe of the tonsil expands upward into the culdesac which forms the superior angle of the sinus, the walls of which sur- round it like a hood. Between the two an extensive fossa remains which may be cpiite open or its epithelial surfaces may be in apposition. This is the supratonsillar fossa. Its size varies with the size of the original pocket and also with the height on the outer wall of the sinus to which the root of the tonsil extends. Its faucial opening is more or less covered by the upper part of the plica, so that internally it is continuous with the anterior fossa, and, if one exist, with the posterior fossa. The ventral walls of the sinus surrounding the tonsil have a small amount of lymphoid tissue developed in them, sometimes with shallow cryptic formation. This is especially true of the superior wall of the supratonsillar fossa and of the plica anteriorly. This lymphoid tissue is continuous at the tonsillar root with that of the main bud, and must be considered as forming a part of the same. At times the amount of lymphoid tissue de- DEVELOPMENT OE THE TONSIL 27 voloped in the deeper layer of the plica is so great as to form a thick wedge-shaped mass which is continuous with the main bud of the tonsil at its base. Under these condi- tions the plica has the appearance of being directly at- tached to the tonsil and the anterior fossa is converted into a deep vertical crypt. This is the so-called attached plica. (Fetterolf.) The Development of the Capsule.—The lymphoid tissue of the tonsil is developed entirely within the more super- ficial fibers of the tunica propria of the mucosa. The deeper layers of the propria are pushed aside by this de- velopment and condensation takes place in them, so that they form a thin, compact membrane, the capsule, sur- rounding the lymphoid mass on all sides not covered by epithelium. It is directly continuous with the propria of the surrounding mucosa. Between the capsule and the surrounding muscular walls of the sinus there is a much less compact layer of fibrous tissue, which is continuous with the submucosa of the mucous membrane of the phar- ynx. There is no sharp line of demarkation between it and the capsule on the inner side and the very thin pharyn- geal fascia on the outer side; but the loose disposition of its fibers makes the normal tonsil freely movable in the fossa, a condition which greatly facilitates tonsillectomy and makes possible the so-called split capsule operation. It is this tissue that should be left lining the fossa in all cases, whatever the method of removal of the tonsils may be. The fibrous trabeculae, which extend from the inner side of the capsule into the lymphoid tissue, have the same derivation as the capsule. Theoretically the individual units of the tonsil, each composed of a crypt with its sur- rounding lymphoid tissue, are separated from each other laterally by the fibrous mucosa, and there are as many trabeculae as there are crypts, the fibrous fingers on the one side being dovetailed with those of epithelium on the other. The majority of these trabeculae are, however, com- 28 THE T0HSILS pletely infiltrated with lymphocytes, their fibers making up the fine reticulum of the diffuse lymphoid tissue. A few remain well marked, two or three being the usual number seen in a longitudinal section. Histogenesis of the Tonsil.—The origin of the lympho- cytes of the tonsil as well as of other lymphoid organs, is a question upon which observers are not agreed. They are, however, probably of mesodermal origin (Stohr, 1 laminar, Ivollman, Griinwald); but whether they migrate from the blood vessels into the connective tissue (Stohr), or are derived from the fixed cells of the mesoderm (Hainmar), is not known. Retterer’s5 theory that they are derived from metaplasia of the epithelial cells of the tonsillar buds, seems untenable. It owes its conception to the supposed epithelial origin of the small cells of the thymus, and to the well known changes which take place in the cryptic epi- thelium of the tonsil. Neither the origin nor the character of the small thymus cells have, however, as yet been defi- nitely determined; and the lymphoid tissue of the tonsil often becomes well developed, even with follicle formation with germinal centers, before any marked degeneration of the epithelium takes place. 5Histogenese du Tissu Reticule aux depens de l’Epithelium, Anat. Anz., Bd. 13, 1897. Explanation to Fig. 5. Diagrams Illustrating the Development of the Tonsil. (See opposite page.) The left-hand figure in each row represents the sinus tonsillaris at the fourth month of foetal life before the appearance of tonsillar tissue. The succeeding figures show the gradual development of the tonsil and explain the relationship which it assumes to the surrounding tissues. The upper four figures are in cross-section and show the development of the tonsil with a free plica. The middle row, also in cross-section, shows the development of the attached plica. The lower row, in longitudinal section, shows the develop- ment of the tonsil and the formation of the supratonsillar fossa. A. Sinus tonsillaris. B. Faucial epithelium. C. Fibrous mucosa. D. Muscle fibers of anterior pillar. E. Posterior pillar. F. Plica triangularis. H. Superior constrictor of the pharynx. Iv. Epithelial bud—the aulage of the crypt. L. Fibrous trabecula springing from M—the capsule. N. Anterior fossa. P. Posterior fossa. B. Crypt in the plica. S. Muscle fibers of the palate. T. Supratonsillar fossa. DEVELOPMENT OF THE TONSIL 29 Fig. 5. CHAPTER III THE ANATOMY AND HISTOLOGY OF THE TONSILS The Anatomy and Histology of the Faucial Tonsil The faucial tonsil is a globular mass of lymphoid tissue lying, one on either side of the fauces, in a recess (the sinus tonsillaris), which is formed by the palatal arches. It is the largest of the lymphoid nodules of the respiratory and alimentary tracts, and di ffers from other such nodules only in its size, its compactness, and in the extent and complex- ity of its crypts. It may be nearly spherical in shape, though it is usually much greater in its longitudinal than in its anteroposterior diameter, and is somewhat com- pressed from within outward. It has an internal and ex- ternal surface, an anterior and a posterior border, and a superior and an inferior pole. It is originally developed in two lobes, a lower and an upper, which become fused shortly before birth. Their line of demarcation may often be seen after the full development of the organ. It is at- tached to the walls of the sinus by a root which includes a variable portion of its outer surface and of its anterior and posterior borders. This attached surface is covered by a fibrous membrane, the capsule, which is continuous with the fibrous mucosa of the surrounding mucous mem- brane. From its inner surface there extends a series of fibrous trabecula? which divide the tonsil into lobes. All other surfaces of the tonsil are covered by epithelium. It presents on its epithelial surface the openings of from ten to twenty pits or crypts, which extend deeply into its sub- stance practically as far as the capsule. The Crypts may be single and without noticeable change 30 A 1STATOMY AND HISTOLOGY OF THE TONSILS 31 in calibre throughout their length; or they may be exten- sively branched and their calibre much greater below the surface than their faucial openings would indicate. Their walls are normally in aj)position; yet the accumulation of cellular debris within them is so frequent that a mild degree Fig. 6.—Tonsil of childhood. The relation of the capsule to the plica triangularis. The plica is shown at the extreme left of the figure as a thin band of tissue, to the right of which is the anterior fossa. The faucial layers of the plica do not appear in the cut, as they were not removed during the operation. The line of incision is seen near the tip of the plica, extend- ing through its faucial layers to the capsule which bounds the upper and left sides of figure. There is a slight amount of lymphoid tissue developed in the plica. 32 THE TONSILS of the irregular pocketing that results cannot he considered abnormal. The crypts extend in a general outward direc- tion; those that empty into the supratonsillar fossa extend downward and outward. These latter drain poorly both on account of their direction and because of the closed con- dition of the fossa. The same is also true of the crypts that empty behind the plica triangularis. The Sinus Tonsillaris, the walls of which surround the tonsil on all but its inner side, is a triangular depression bounded anteriorly by the anterior faucial pillar (palato- glossus muscle), posteriorly by the posterior faucial pillar (palato-pharyngeus muscle), superiorly by the tissues of the soft palate, and externally by the superior constrictor muscle of the pharynx. It is deep above, where it may end at the apex formed by the junction of the pillars; or it may extend considerably above this point into the tissues of the soft palate, which form a dome-shaped matrix for the superior pole of the tonsil, surrounding it like a hood. It becomes progressively more shallow as the line of the in- sertions of the pillars is approached, at which point, just above the base of the tongue, it disappears altogether. The Plicae.—The anterior and posterior boundaries of the sinus may be augmented internally in varying degree, and an inferior boundary established, by two folds of mu- cous membrane, the plica triangularis and the plica retro- tonsillaris, which extend from the internal border of the . . anterior and posterior pillars respectively. In their orig- inal state, and before the bulk of the growing tonsil has filled the sinus, they form an incomplete inner wall to the sinus,—a sort of hymen with longitudinal perforation ex- tending parallel to the posterior pillar. AVith the growth of the epithelial buds and the deposition of lymphoid tissue around them, the plicae assume a calyx-like relation to the expanding mass of the tonsil. They are reduplicated folds of mucosa with their fibrous layers in apposition. They, therefore, are composed of four layers, disposed from ANATOMY AND HISTOLOGY 0L<1 THE TONSILS 33 within outward as follows: faucial epithelium, fibrous mucosa, fibrous mucosa, sinus epithelium. A varying amount of lymphoid tissue, sometimes with shallow cryptic Fig. 7.—Tonsil of childhood. The development of the attached plica. Plica shows at the left side of the figure with a moderate amount of lymphoid tissue developed in it. Both the plica and the anterior fossa may still be recognized as such. More pronounced development of lymphoid tissue in the plica makes its recognition difficult, as it then appears to be a part of the main lobe of the tonsil. formation, is developed in the third of these layers. It may form a thin, almost microscopic thickening, with sharp line of demarcation between it and the lymphoid tissue of the 34 THE TONSILS main bud of the tonsil at its root. It often, however, forms a wedge-shaped mass of tissue whose base is directly con- tinuous at the tonsillar root with the lymphoid tissue of the main mass. The result is an attached plica. (Fetterolf.) (Fig. 7.) The Plica Triangularis is constant, but varies much in its extent. In its most developed form it is a right angle triangular web of folded mucosa with its apex attached to the uppermost part of the inner border of the posterior pillar, its perpendicular attached to the inner border of the anterior pillar, and its base inserted into the lateral pharyngeal wall just above the base of the tongue, along a curved line, corresponding with the line of attachment of the tonsil interiorly. It covers from above downward a progressively increasing area of the anterior internal sur- face of the tonsil, encircling its lower pole like a sling. With the forward growth of the tongue the inferior inser- tion of the plica may undergo a greater or less reduction, so that it may appear only as a very inconspicuous fringe of mucosa extending slightly beyond the inner border o! the anterior pillar over the anterior border of the tonsil. Between these two extremes all gradations may be seen. The Plica Retrotonsillaris is inconstant. When it ex- ists it is continuous above with the apex of the plica trian- gularis; and with the same structure below, when the in- ferior insertion of that fold extends to the posterior pillar. In the latter case the combined folds form a complete ring round the internal border of the sinus. The Root of the Tonsil.—The sinus tonsillaris is in the beginning a deep culdesac, lined completely with faucial mucosa. With the development of the crypts in the mucosa of its deeper parts and the deposition of lymphoid tissue around them, the epithelium is separated from its fibrous mucosa and expands in all directions except externally, so that the tonsillar mass which it covers, eventually not only fills the sinus but bursts through its faucial opening into ANATOMY AND HISTOLOGY OF THE TONSILS 35 the faucial cavity. That portion of the walls of the sinus concerned in this development constitutes the point of at- tachment, or root of the tonsil. It varies in size, sometimes being confined to the outer wall; often, however, extending internally over the anterior and posterior walls, even to their internal borders. The superior angle of the sinus is never involved in the development of the main lobes of the tonsil, though it usually has a thin layer of lymphoid tissue developed in it which is continuous on all sides, ex- cept internally, with the lymphoid tissue of the upper pole. Between the epithelial surfaces of the tonsil and the sur- faces of the sinus not covered by the root of the tonsil a series of culdesacs remain. Their depth depends upon the original depth of the sinus, the extent of the plica and the size of the tonsillar root. The superior and anterior of these are of great clinical importance. The Superior or Supratonsillar Fossa lies between the su- perior pole of the tonsil and the superior angle of the sinus. It is constant. It may be a distinct space, triangular in shape, with its faucial opening more or less completely covered by the upper segment of the plica, which at this point is sometimes called the plica supratonsillaris. When the sinus extends high into the palate, the superior lobe of the tonsil pushes its way into this superior cavity and the supratonsillar fossa is reduced to a blind epithelial sac with walls in apposition. It may be very extensive, often admitting a probe as far as the plane of the external sur- face of the tonsil. A variable amount of lymphoid tissue is developed in its superior wall. (Fig. 8.) The Anterior Fossa lies between the anterior-internal sur- face of the tonsil and the anterior pillar and plica trian- gularis. (Figs. 6 and 7.) Its surfaces are always in apposition. Superiorly it is continuous with the more super- ficial part of the supratonsillar fossa. In cases of extreme development of the plica it is continued downward and 36 THE TONSILS backward round the inferior pole of the tonsil to the pos- terior pillar. A Posterior Fossa exists when a plica retrotonsillaris is present, and is continuous above with the more superficial part of the supratonsillar fossa. In cases where all the plica) are present and in full development the combined Fig. 8.—Tonsil of childhood. The relation of the capsule to the supra- tonsillar fossa. (Upper part of figure.) No follicles are present in the superior wall of the fossa, which is often much thickened by shallow cryptic formation and the development of numerous follicles. fossa) form a complete moat round the tonsil, comparatively shallow everywhere except at the superior angle where the supratonsillar fossa extends over the superior pole of the tonsil to the plane of its outer surface. The Capsule covers all surfaces of the tonsil not covered ANATOMY AND HISTOLOGY OF THE TONSILS 37 by epithelium. Theoretically it includes only that part of the deeper layers of the fibrous mucosa of the sinus that covers the attached surface of the main bud of the tonsil. As the mucosa of the more internal surfaces of the sinus, including the pliese, have lymphoid nodules developed in them, often directly continuous at the root of the tonsil with the lymphoid tissue of the main mass, it seems best to consider the capsule as including the fibrous mucosa of the entire sinus, even to the internal rim of the plicie. At this point it is folded upon itself and becomes the fibrous layer of the faucial mucosa. It will be appreciated from the above description that the tonsil lies in and not under the mucous membrane; that it is in reality simply a complicated mucous membrane with lymphoid nodules developed in the more superficial fibers of its tunica propria. If this fact is kept in mind, the re- lations of its various parts to each other and to the sur- rounding tissues are easily understood. Types of Tonsil.—Two distinct types of tonsil exist, the pedunculated and the buried. The pedunculated tonsil is nearly spherical in shape, is attached by a small base to a shallow sinus and appears prominently in the fauces, the walls of the sinus hiding little but its external surface. Because of its extreme prominence it is usually called hy- pertrophied, yet it may not be excessive in size, the average being much smaller than in the buried type. The buried tonsil has a broad base attached to a deep sinus. The cul- desac at the superior angle is especially marked and the superior lobe of the tonsil is firmly held in place and almost completely hidden by its walls. The tonsil may not appear internally beyond the plane of the pillars. This type of tonsil may be very large without giving any indication of it to the casual observer. It is only when it is pulled in- ward with a tenaculum or is thrown inward by the muscles of the palate during gagging, that its size may be appre- ciated. The buried tonsil, however, often extends internally 38 THE TONSILS far beyond the pillars, showing as prominently in the fauces as the pedunculated tonsil. The largest tonsils are of this type. The Blood Supply of the Tonsils.—The Arteries.—The tonsil is an extremely vascular organ, receiving its blood supply from the tonsillar and palatine branches of the fa- cial, from the descending palatine branch of the internal maxillary, from the dorsalis linguae of the lingual and from the ascending pharyngeal. Its chief blood supply is from the tonsillar and ascending palatine branches of the facial. Usually two or three small twigs are given off from the former and one from the latter, though the reverse ar- rangement may be found. These branches pierce the su- perior constrictor opposite the lower pole of the tonsil, ascend for a variable distance on the external capsular surface, and enter the tonsil in its lower half. They are the most important arteries of the tonsil from the surgical standpoint as they are the ones most often involved in post- operative bleeding. The descending palatine sends a small branch to the superior lobe which enters its-external sur- face. The dorsalis linguae supplies the anterior pillar, giving off branches which enter the tonsil along its anterior border, usually in its lower half. Sometimes a branch in the upper segment of the pillar bleeds freely. A branch from the ascending pharyngeal enters the tonsil from the posterior pillar usually in its lower part. The bleeding from the arteries of the pillars is more easily seen and con- trolled by hemostats and ligature than is the case with those from the facial and ascending palatine which are deep within the lower half of the sinus tonsillaris. I have never seen the superior artery give rise to serious bleeding, though many instances of it have been reported. The Veins of the tonsil form a plexus lying in the walls of the sinus. According to Fetterolf1 the largest vessel of 1Fetterolf, G.: The Anatomy and Relations of the Tonsil, etc., Amer. Jour. Med. Sci., July, 1912. ANATOMY AND HISTOLOGY OF THE TONSILS 39 tlie plexus runs down the outer edge of the palato-pharyn- geus muscle and joins with veins from the epiglottis and the base of the tongue, forming a large trunk which empties into the pharyngeal plexus. A smaller vein runs down the anterior sinus wall and empties into the lingual veins. The first of these vessels may sometimes be seen after a tonsil- lectomy, lying superficial in the posterior sinus wall. These veins are of great importance from the operative standpoints as they may give rise to severe bleeding if they are cut. Injury to them might also result in the intro- duction into the venous circulation of minute septic thrombi,—one of the reasonable explanations of the causa- tion of postoperative pulmonary abscess. The etiology of this condition is discussed in a later section. The Lymphatics of the Tonsils.—No afferent lymphatic stems have been demonstrated leading to the tonsils. Lenart2 has shown by a series of experiments on animals that inert coloring matter injected into the mucosa of the turbinate bodies of the nose, finds its way not only into the tonsil of the same side but even into that of the other side. The amount of coloring matter that entered the tonsil, how- ever, was apparently insignificant compared to the amount found in the upper deep cervical glands. Lenart’s results have recently been corroborated by Henke,3 who has found colored particles in the tonsils not only after injections in the nasal mucosa but also following injections into the gums. Neither investigator, as it seems to me, has suc- ceeded in proving the existence of definite lymphatic stems from this wide field to the tonsils. Fraenkel4 lias called attention to the frequency with which acute infections in the nose are followed by tonsillitis; and Wright5 and others 2Lenart, Z.: Fxperimentelle Studien liber den Zusammenhang des Lymphgefass-systems der Nasenhohle und der Tonsillen, Arch. f. Laryngologie, 1909, xxi. 3Henke, F.: Die Physiologische Bedeutung der Tonsillen, Arch. f. Laryngologie, 1914, xxviii. 4Fraenkel, B.: Die infektiose Natur der Tonsillitis lacunaris, Arch. f. Laryngologie, iv. 5Wright, G. H.: A Functional Relation of the Tonsils to the Teeth, Boston Med. and Surg. Jour., May 20, 1909. 40 THE TONSILS claim that the tonsils regularly enlarge during the periods of dentition. The phenomenon in both instances is ascribed to a lymphatic connection between the tonsil and the pri- mary source of irritation. While this may not definitely be Fig. 9.—Diagram showing the upper cervical lymphatic glands. The ton- sil gland is shown in its normal position, just under the anterior edge of the sternomastoid muscle. Directly in front of it, under the angle of the jaw, is the posterior submaxillary gland. Notice that no lymphatics lead from the deep glands under the sternomastoid to the tonsil gland. AXATOMY AND HISTOLOGY OF THE TOXSILS 41 denied, it may be said that anatomical proof of the asser- tion is as yet wanting. The efferent lymphatics of the tonsil pass through the fibrous trabeculae and the capsule, pierce the superior con- strictor muscle of the pharynx and empty into the tonsillar gland (Wood), one of the superior deep cervical nodes lying under the anterior border of the sternocleidomastoid mus- cle, in the angle between the internal jugular and facial veins. It is one of the most constant in position of all the cervical nodes. When enlarged it projects anteriorly be- yond the anterior border of the sternomastoid and appears superficially from one-half to three-quarters of an inch below the angle of the jaw. As cases of cervical adenitis are so often sent to us with the question, “Is the tonsil the source of the infection?” and as the tonsillar gland or the glands in its immediate vicinity receive their afferents from so many different parts, lesions of which may give rise to adenitis easily confounded with that due to infection through the tonsil, a brief description of the deep cervical glands will be given here. The deep cervical nodes are divided into a superior and an inferior group. The superior nodes, ten to sixteen in number, extend along the course of the internal jugular vein from the tip of the mastoid to the level at which the vein is crossed by the omo-hyoid muscle. From the clinical standpoint they may be divided into an anterior and a pos- terior group. The posterior glands lie deep under the sternomastoid or along its posterior border. They receive their afferents from the superficial nodes in the suboccipital and mastoid regions, from the retro-pharyngeal glands, and also directly from the mucosa of the pharynx and naso- pharynx and the nasal mucosa posteriorly, including that of the posterior sinuses. When enlarged they are difficult to feel as discrete nodes but form an indefinite swelling under the sternomastoid. Any infection in the wide field from which their afferents are derived may cause their 42 THE TONSILS enlargement. Pediculosis and lesions of tlie lateral and posterior pharyngeal nodules are frequently overlooked in this connection. Their enlargement without involvement of the anterior glands cannot be attributed to the tonsil. The anterior glands form a chain lying just under the an- terior border of the sternomastoid. They receive their afferents from the tonsil and the base of the tongue and from the submaxillary and submental nodes. Stems from the body of the tongue also pass directly to one of the an- terior glands which lies somewhat below the tonsillar gland. The most posterior of the submaxillary glands is com- monly confounded with the tonsillar gland. It is situated just under and anterior to the angle of the jaw. It is never enlarged from infection through the tonsil. One of the most common causes of its enlargement, beyond perfectly obvious lesions of the gums, tongue or cheeks, and one that is frequently overlooked, is an abscess round an old tooth root. An x-ray plate may be necessary to demonstrate this. If the tonsillar gland enlarges alone and there is no lesion at the base of the tongue, the enlargement may be attributed to infection through the tonsil. If the sub- maxillary glands are involved at the same time, the source of the infection should be looked for anteriorly. Cases in which the posterior cervical glands are involved coinci- dently with the tonsillar gland are difficult to decide. If it is possible for a gland to be infected through its efferent lymphatics, the tonsils might be the cause of enlargement of the posterior group. In most of these cases, however, the infection is undoubtedly of double origin, the lateral and posterior pharyngeal nodules or the adenoid tissue of the vault being responsible for the posterior enlargement. The inferior group of the cervical lymph nodes receive afferents directly from the upper nodes. They are of im- portance in connection with the tonsil chiefly because of the possibility of tuberculous infection reaching the pul- ANATOMY AND HISTOLOGY OF THE TONSILS 43 monary apices via this route. Grober’s0 experiments on animals showed that the supraclavicular glands form the connecting link between the upper deep cervical nodes and the apical pleura and that inflammatory adhesions may ex- tend the infection to the apices themselves. Wood states that the supraclavicular group only rarely receive afferents from the upper cervical glands, the efferents of which gradually converge and form the jugular trunk, which empties into the subclavian vein at its junction with the internal jugular. According to the same authority,7 tuber- culous infections may reach the apices either by the supra- clavicular route, or occasionally through an inconstant gland of the upper anterior group which is sometimes found in the notch formed by the junction of the internal jugular and subclavian veins, and is very closely placed to the parietal pleura of the pulmonary apex. In view of the frequency with which primary tuberculosis of the tonsils occurs, the existence of this possible line of invasion be- tween them and the lungs assumes a clinical importance. That this mode of pulmonary infection is frequent, how- ever, is doubtful. The Nerve Supply of the Tonsils.—The nerve supply of the tonsils is derived from the sphenopalatine or Meckel’s ganglion through the middle and posterior palatine nerves and from the glossopharyngeal. Fibers from these two sources unite to form a plexus around the tonsil (circulus tonsillaris). The Relations of the Tonsil.—The tonsil is so placed that its posterior-inferior limits are just in front of and above the angle of the jaw. It can never be felt on the outside except in cases of malignant growth. On the other hand, a sponge held in the sinus after tonsillectomy and pressed backward and downward may easily be grasped with the 6Grober, J.: Die Tonsillen als Eintrittspforten fiir Krankheitserreger, besonders fur den Tuberkelbazillus, Klin. Jahrbuch, 1905, xiv. 7W»od, G. B.: The Tonsils and Tuberculosis, Penn. Med. Jour., June, 1912. 44 THE TONSILS fingers behind and below the jaw. This is of importance in postoperative bleeding, as the pressure between the sponge on the inside and the fingers on the outside may be brought to bear directly on the posterior inferior angle of the sinus where bleeding is most likely to occur. In- teriorly the tonsil is in relation with the base of the tongue and the lingual tonsil, from which it may be separated by the lower segment of an extensive plica triangularis; other- wise the two lymphoid masses may be directly contiguous. These lingual nodules should not be mistaken for the lower pole of the tonsil and snipped off with a punch after ton- sillectomy, as deep wounds in this region are prone to cause protracted venous bleeding. Superiorly the tonsil is in relation with the soft palate, into which it may mound con- siderably above the junction of the pillars. It never ex- tends high enough to produce pressure on the eustachian orifices. It may, however, affect the patency of the tubes by interfering with the muscles of the palate, particularly with the tensor pabiti. Externally the tonsil lies directly on the superior constrictor muscle of the pharynx, to which it is but loosely attached except at its lower pole where its larger vessels enter. Between the two there is a theoret- ical space, in which abscess formation often takes place (peritonsillar abscess). External to the superior con- strictor is the pliaryngomaxillary space. It is filled with fat and areolar tissue continuous with that of the carotid sheath. It is divided into a posterior and an anterior part by the stylopharyngeus and styloglossus muscles, the first part being in relation with the internal carotid artery and the internal jugular vein, and the second in relation with the tonsil. In rare cases when pus from a peritonsillar abscess has entered the anterior space, this barrier forms a further protection to the carotid sheath. A long styloid process occasionally extends into the anterior space, and may even pierce the constrictor and the tonsillar capsule. It may render a tonsillectomy difficult. In many of these ANATOMY AND HISTOLOGY OF THE TONSILS 45 cases, however, the bone is not of styloid origin, but is a true osteoma. The internal carotid artery lies two cm. (% in.) behind and external to the posterior pillar (Zucker- kandl). Except in cases of anomalous position it is in no danger of being wounded during tonsillectomy, nor in the opening of a peritonsillar abscess anteriorly. If the ab- scess points behind the posterior pillar, however, great care should be taken. Aneurism of the internal carotid should be thought of in cases of swelling in this region. The Normal Histology of the Tonsil The tonsil is composed of lymphoid tissue supported by a fibrous framework—the capsule and its trabeculae. Its inner surface is covered by epithelium which is continuous with that which lines the crypts throughout their extent. The epithelium extends outward to the root of the tonsil where it is reflected upon the internal surface of the folds of mucosa which constitute the plicae. At the free border of these folds it is again sharply reflected so as to cover their faucial surfaces, from which point it is continuous with the epithelium of the general faucial mucosa. The capsule with its trabeculae on the outer side forms an in- verted replica of the epithelium with its cryptic prolonga- tions on the inner side; the two are dovetailed, so to speak, and are separated at any given point only by the develop- ment of a thin layer of diffuse lymphoid tissue in which a single row of follicles, more or less regularly disposed, is embedded. The blind ends of the crypts, therefore, are in close relation to the capsule. The two are never in appo- sition, but the amount of lymphoid tissue between them is so slight that the crypts may be said, for all practical pur- poses, to extend to the capsule. The trabeculae are by no means as numerous as the crypts, owing to the fact that many of them are completely taken up by the lymphoid development, so that the diffuse tissue surrounding a crypt 46 THE TONSILS may be continuous with that of its immediate neighbors without fibrous demarcation between them. The general character of the lymphoid tissue has already been described (p. 18). The Capsule is composed of the deeper layers of the tunica propria of the mucosa of the sinus tonsillaris, sepa- rated from its epithelium by the development, in its more superficial layers, of the lymphoid tissue which composes the mass of the tonsil. It covers the root or attached sur- face of the tonsil, from which it extends into the calyx-like folds of surrounding mucosa, at the inner edge of which it is continuous with the tunica propria of the faucial mucosa. It is somewhat more compact than the propria elsewhere. It is composed of fibrous tissue, with numerous elastic and striated muscle fibers interspersed. The muscle fibers are derived from the superior constrictor of the pharynx and from the palatal muscles. A number of mucous glands are found in the capsule, being especially numerous at the sides opposite the faucial pillars. Blood vessels appear at inter- vals, the larger of which are seen at the junction of the trabeculae with the main capsule, from which point they supply the tonsil through the trabeculae. Bone and car- tilage are occasionally found in the capsule. Their pres- ence may make the dissection of the tonsil difficult. The trabeculae are of the same composition as the capsule, ex- cept that muscle fibers are only occasionally found in them, and then only near their junction with the capsule. At this point the trabeculae are of good size, but become rapidly attenuated as they approach the epithelial surface where they are lost in the fine reticulum of the lymphoid tissue. The Crypts may be simple; usually, however, they are extensively and irregularly branched. Their caliber varies at different depths. In a strictly normal tonsil I suppose the epithelial surfaces of the crypts should lie in apposition throughout their whole course. I have yet to examine such a tonsil. The nearest approach to this ideal that I have ANATOMY AND HISTOLOGY OF THE TONSILS 47 found is one in which the inequalities are not sufficient to cause any considerable accumulation of detritus in the crypt. In the great majority of tonsils that are removed, either on account of their size or for the relief of consti- Fig. 10.—Cross section of tlie human tonsil of six months. The lymphoid tissue is diffuse, only slight suggestions of follicles being present near the crypt in the lower left quadrant. Some of the crypts are still in the de- velopmental stage. All have as yet an intact epithelium. tutional disturbances, marked pocketing of the crypts is found. These pockets may occur at any point. They are quite as apt to be deep as superficial. They are often 48 THE TONSILS found in close relation with the capsule, where they are formed at the blind end of the crypts. The Epithelium.—The surface epithelium is of the strati- fied squamous variety. It is compact, many layers in thick- Fi