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Frommel, Zur Hixtologie und Physiologic der Milchdruse, Centralbl. f. Gynakologie, 1891.

Truman, E. B., The colostrum corpuscle of human milk, Lancet, 1888, vol. ii.

"Williams, Koger, Polymastism with special reference to mammce erraticce and the development
of neoplasms from supernumerary mammary structures, Jour. Anat. & Phys., vol. xxv., 1891 ;
Mammary variations per defcctum, Ibid.

"Wylie, W., Case of entire absence of both mammce in a female, aged twenty-one years, Brit.
Med. Journal, 1888, vol. ii., p. 235.



THE DUCTLESS GLANDS.

BY E. A. SCHAFER AND J. SYMINGTON.



THE remaining organs to be described all belong to the class of bodies known as
ductless glands. Some of these, such as the lymphatic glands, have been described
in the General Anatomy (Vol. I., Pt. 2) ; others, such as the solitary and agminated
glands, the pituitary body and the pineal gland, with the viscera to which they are
structurally connected. There remain to be noticed here the spleen, the suprarenal
capsules, the thymus gland, the thyroid body with the parathyroids^ and the small
vascular nodules termed carotid and coccygeal glands.



THE SPLEEN.

The spleen (figs. 301 and 304) is a soft, highly vascular and easily distensible
organ of a dark purplish colour. It is placed obliquely behind the stomach, its upper
and inner end being in the posterior part of the epigastric region, while the lower,
outer and larger portion is in the left hypochondrium. Its long axis, which on an



s.v.




Fig. 301. HORIZONTAL SECTION OF THE ABDOMEN OP AN ADULT MALE AT THE LEVEL OF THE LOWER

BORDER OF THE BODY OF THE TWELFTH DORSAL VERTEBRA, SEEN FROM ABOVE. NEARLY |. (J. S. )

L, K, left kidney ; d.d, diaphragm ; s.c, left suprarenal capsule ; S. V, splenic vein ; St, stomach ;
G.S.O, gastro-splenic omentum ; L.S, lesser sac of the peritoneum.

average measures five to six inches, nearly corresponds with that of the lower ribs,
and the organ usually extends from the level of the eighth rib above to the eleventh
below. It is the largest of the ductless glands.

Surfaces and borders. When hardened in situ the spleen has, according to
Cunningham, the shape of an irregular tetrahedron, with its apex above and its base
below. Its four surfaces are termed phrenic, renal, gastric, and basal. Of these the
phrenic is large and convex, and lies against the diaphragm. In the greater part of
its extent it looks upwards, backwards, and to the left, but near its upper end some-



294



THE DUCTLESS GLANDS.



what inwards. It is. separated from the eighth, ninth, tenth, and eleventh ribs not
only by the peritoneum and the diaphragm, but also in part of its extent by the left
pleura and lung. The left lobe of the liver is occasionally found to extend back-
wards and to the left between the upper part of the phrenic surface and the
diaphragm. The renal surface is generally flat, and narrower than the gastric, and
does not reach so high as either the gastric or phrenic surfaces. Above, it generally
touches the suprarenal capsule, and in the rest of its extent is in relation with the
outer aspect of the left kidney. It looks inwards and downwards. The gastric
surface is concave, and looks forwards and inwards. In the great part of its extent




Fig. 302. VIEW OP THE ABDOMINAL VISCERA FROM BEHIND, AFTER REMOVAL OF THE SPINAL COLUMN,

THE WHOLE OF THE POSTERIOR WALL OF THE ABDOMEN AND THE KIDNEYS AND SUPRARENAL

CAPSULES, THE PERITONEUM BEING LEFT (this and the next figure are taken from Prof. His'
models). ^

P, pancreas ; P', its head ; d, duodenum ; st, stomach ; spl, spleen ; R.L., right lobe of the liver ;
L.S., Spigelian lobe ; v.c.i., \ena cava inferior ; p.r., portal vein ; b, common bile duct ; i.r., impres-
sion for the right kidney on the posterior surface of the liver ; the situation of the two kidneys is well
shown by the corresponding impressions in the cast; asc. col., desc. col. , ascending and descending
colon ; pt, back of the peritoneum ; TO, line of attachment of the mesentery ; VIII, IX, X, XI, the
corresponding ribs ; il, ilium.



it lies against the posterior surface of the stomach, but towards its lower end it
touches the tail of the pancreas. This surface presents, parallel with and near its
inner border (see fig. 304), a long fissure, or, more frequently, a series of depressions,
termed the hilum, through which the vessels and nerves enter the spleen, and around
which the peritoneum is reflected from the surface of the organ. The upper and
inner extremity of the spleen is directed inwards, and reaches to within about an
inch of the left side of the vertebral column, usually opposite the body of the eleventh
dorsal vertebra. The lower and outer end is blunt, and presents a triangular area,
which may be termed the basal surfaca (Cunningham). It lies against the tail of
the pancreas, the splenic flexure of the colon and the costo-colic ligaments. Of



THE SPLEEN.



295



the borders of the spleen the anterior, situated between the gastric and phrenic
surfaces, is the most prominent, and is usually marked near its lower end by one or
two notches. Traced from its inner end, it is seen to curve outwards with the
convexity of the curve upwards. This part of the anterior border reaches forwards
and upwards between the diaphragm and the stomach nearly as high as the fimdus of
the stomach. Towards the left side this border turns downwards and somewhat
forwards, being in close contact with the chest wall near the mid-axillary line and
opposite the eighth, ninth, and tenth ribs. It generally terminates in a prominent
angle. The inner border lies slightly internal to the hilum, and separates the gastric
and renal surfaces. The posterior border is between the renal and phrenic surfaces.
In some cases it is very well marked, dipping slightly inwards between the diaphragm




Fig. 303. THE PANCREAS AND ADJOINING VISCERA FROM BEFORE. *

The liver, the stomach, the greater part of the small intestine, and the transverse colon have been
removed. P, pancreas ; d, duodenum ; d.j., duodeno-jejunal flexure ; above the duodenum, and
between it and the head of the pancreas are seen the bile duct, portal vein, and hepatic artery ; asc.
col., desc. col., ascending and descending colon ; spl., spleen ; r.k., l.k., right and left kidneys ; s.r.,
s.r', right and left suprarenal capsules ; pt, peritoneum at the back of the abdominal cavity ; m, line
of reflection of the mesenter./ ; the line of reflection of the transverse mesocolon is seen along the lower
edge of the pancreas and crossing the duodenum.



and the kidney. It is inclined downwards and outwards opposite the lower border
of the eleventh rib. A lower border separates the phrenic and basal surfaces.

Relation to peritoneum. The spleen is almost entirely covered by peri-
toneum which is firmly connected with its capsule. It also gives attachment to two
peritoneal folds the gastro-splenic omentum and the lieno-renal ligament. The
gastro-splenic omentum consists of two layers of peritoneum, which pass from the
front of the hilum of the spleen forwards and outwards to the posterior surface of
the stomach near its left border. If the outer of these layers be traced over the
spleen it will be found to cover the gastric surface to the left of the hilum, the
phrenic surface and the posterior part of the renal surface. It is then reflected on
to the kidney, forming the posterior layer of the lieno-renal ligament. The inner
layer of the gastro-splenic ornentum is derived from the lesser sac, and is continued
into the anterior layer of the lieno-renal ligament. Below, the two layers of the
gastro-splenic omentum are continuous with the gastro-colic ornentuin. The
splenic vessels pass to the spleen between the layers of the lieno-renal ligament.



296 THE DUCTLESS GLANDS.

The spleen varies in magnitude more than any other organ in the body ; and this
not only in different subjects, but, as may be ascertained by percussion, in the same
individual under different conditions. On this account it is difficult or impossible
to state what are its ordinary weight and dimensions. In the adult it may vary in
weight from 100 grammes to 300 grammes, the average being about 170 grammes ;
it generally measures 120 to 130 mm. (five or six inches) in length, and the breadth
of the phrenic surface is 70 to 80 mm. ; its volume varies enormously, but
usually does not exceed 200 to 300 cub. cent. After the age of forty the average
weight gradually diminishes. In intermittent and some other fevers the spleen is
much enlarged, reaching below the ribs, and often weighing as much as 18 Ibs.
to 20 Ibs.

Accessory spleens. Small detached roundish nodules are occasionally found in the
neighbourhood of the spleen similar to it in substance. These are commonly named accessory
or supplementary spleens (gplenovli. llenmlt). One or two most commonly occur, but a greater
number, and even up to twenty-three, have been met with. They are small rounded masses




Fig. 304. THE SPLEEN OF AN INFANT FIVE DAYS OLD, HARDENED IN SITU BY THE CHLORIDE OF

ZINC METHOD. DRAWN FROM A MODEL PREPARED BY A. F. DlXON.

G, gastric surface ; R, renal surface ; B, basal surface ; A, anterior border ; A.I, antero-internal
or inner border; P.I, posterior or postero-internal border; I.B.A, internal basic angle; A.B.A,
anterior basic angle ; H, hilum.

varying from the size of a pea to that of a walnut. They are usually situated near the lower
end of the spleen, either in the gastro-splenic omentum or in the great omentum.

Spleen in the infant. The spleen is relatively slightly larger in the new-born child
than in the adult, but the peculiarities in the infant are mainly due to the large size of the
liver and suprarenal capsule. The under surface of the left lobe of the liver is normally in
contact with it at birth, and, according to Ballantyne, the hepatic area of the spleen is larger
than any of the other surfaces. The same observer suggests that the renal surface in the
new-born infant is more appropriately named the suprarenal, as this organ lies in contact
with it and separates it in almost the whole of its extent from the kidney.

STRUCTURE OF THE SPLEEN.

The spleen has two membranous investments a serous coat derived from the
peritoneum, and & fibrous coat (tunica propria). The soft substance (pulp) of the
organ is supported by a reticular framework of fibrous and muscular bands
(trabeculw).

The serous coat is thin, smooth, and firmly adherent to the tunica propria
beneath. It closely invests the surface of the organ, except at the places of its
reflection to the stomach and diaphragm, and at the hilum.

The tunica propria (fig. 305, A), much thicker and stronger than the serous
coat, is whitish in colour and highly elastic. It is continuous with the trabecular



THE SPLEEN.



297



structure within. Along the hilum -this coat is reflected into the interior of the
spleen, in the form of large trabeculae, supported and enclosed by which run the
blood-vessels and nerves ; so that these are ensheathed by prolongations of the




Fig. 305. VERTICAL SECTION OF A SMALL SUPERFICIAL PORTION OF THE HUMAN SPLEEN (from Kolliker).

Magnified with a low power.

A, peritoneal and fibrous covering ; b, trabeculse ; c c, Malpighian corpuscles, in one of which an
artery is seen cut transversely, in the other longitudinally ; d, injected arterial twigs ; c, spleen-pulp.

fibrous coat. These sheaths ramify with the vessels which they include, as far as
their finer subdivisions, and are connected with numerous trabecular processes
which pass into the interior from the whole inner surface of the fibrous coat. The
iirrangenient of the sheaths and trabeculae may be easily displayed in the spleen of




U



Fig. 306. THIN SECTION OF SPLEEN-PULP, HIGHLY MAGNIFIED, SHOWING THE MODE OF ORIGIN OF A

SMALL VEIN. (E.A.S.)

v, the vein, filled -with blood-corpuscles, which are in continuity with others, U, filling up the
interstices of the retiform tissue of the pulp. At p the blood-corpuscles have been omitted from the
figure, and the branched cells are better seen ; w, wall of the vein. The shaded bodies amongst the red
blood-corpuscles are pale corpuscles.

the ox by pressing and washing out the pulp from a thick section ; and then
they are seen to form a close reticulation through the substance. Thus, the fibrous
coat, the sheaths of the vessels, and the trabeculae, all of a highly elastic nature,
constitute a distensible framework, which contains in its interstices or areolae the



29S THE DUCTLESS GLANDS.

red pulp. These fibrous structures are composed of interlaced bundles of areolar
tissue containing a large amount of fine elastic tissue, and a few plain muscular
fibre-cells. In the spleen of the pig, the dog, and the cat, and to a smaller extent
in that of the ox and sheep, there is a far more abundant admixture of muscular
tissue, and this tissue exhibits a regular rhythmic contractility (Roy).

The pulp of the spleen is of a dark reddish-brown colour : when pressed out
from between the trabeculas it resembles grumous blood, and, like that, acquires a
brighter hue on exposure to the air. In fact, what is thus pressed out from the
dead spleen is mainly clotted blood.

When a thin section which has been treated with dilute solution of potash
is examined under the microscope the pulp is seen to be everywhere pervaded




Fig. 307. KETICULUM OF SPLEEN PUIP SHOWN BY SILVEK-CHROMATE METHOD. THE CAPILLARIES OF A
MALPIGHIAN CORPUSCLE ARE ALSO SEEN. (Oppel.)

1, Malpighian corpuscle ; 2, part of its reticulum ; 3, condensed reticulum around margin of
corpuscle; 4, more open tissue outside this; 5,6, connective tissue of artery; 7, capillaries of
Malpighian corpuscle ; 8, reticulum of pulp immediately investing arteriole.

by a reticulum of fine fibres continuous with the tissue of the trabeculse. These
fibres are in the natural condition covered over and concealed by branched con-
nective-tissue corpuscles, which are of various forms and sizes ; in some parts little
but the intercommunicating branches remaining, in other parts the cells being
larger and flatter and in closer connection (fig. 30G, p). These corpuscles, which
may be termed the reticular cells of the pulp, contain each a round or oval nucleus,
like connective-tissue cells generally : and, in teased-out preparations of the fresh
spleen substance it is not uncommon to find within them yellowish pigment
granules of various sizes. In the young subject the nuclei of many of these cells
have been noticed to be multiple, or to be beset with prominences as if budding.
The interstices between the sustentacular cells are, in sections of the hardened organ,
always found to be occupied by blood (tig. 30G, bl), white corpuscles occurring in
rather larger proportion than in ordinary blood, especially in the neighbourhood of



THE SPLEEN. 299

the Malpighian corpuscles to be immediately described. In close relation to the
branched or flattened cells of the pulp, and occupying some of the smaller interstices
between them, rounded, unbranched cells are seen (spleen-cells], larger-than white
blood-corpuscles, bat otherwise much resembling them. These cells are amoeboid,
and, like the fixed cells of the pulp, often contain both red blood corpuscles in
various stages of disintegration, and clumps of pigment granules. Some observers
have noted the presence of. nucleated red corpuscles (similar to those found in
marrow) both in the splenic pulp and in the blood of the splenic vein.

Bohm and v. Davidoff describe tubular spaces within the pulp of the human spleen, lined by
a " rodded " epithelium like that in the convoluted tubes of the kidney, but they leave the
nature of these spaces unelucidated.

Blood-vessels. The splenic artery and vein, alike remarkable for their great
proportionate size, having entered the spleen by six or more branches, ramify in its
interior, enclosed within the trabecular sheaths already described.

The smaller branches of the arteries have an adventitia derived from the
trabeculge, and pass into the proper substance of the spleen, dividing into small




Fig. 308. SMALL ARTERY FROM THE DOG'S SPLEEN WITH MALPIGHIAN CORPUSCLES ATTACHED.

10 DIAMETERS. (Kolliker. )

tufts of arterioles arranged in pencils (fig. 308). But before they thus terminate,
the adventitious fibrous coat which is prolonged over them from the trabeculse
becomes transformed into lymphoid tissue, which forms a comparatively thick sheath
along each. This lymphoid sheath is abruptly dilated here and there into small
oval or spheroidal enlargements, measuring on an average O3G mm. in diameter, but
varying in size from much smaller than this up to 1 mm., and closely resembling
the lymphoid follicles met with in the intestine and elsewhere. These lymphoid
expansions may be seen on the surface of a fresh section of the organ as light-
coloured spots scattered in the dark substance composing the pulp, and have been
long noticed and described as the Malpighian corpuscles of the spleen (fig. 305, c c,
fig. 308). In some cases the corpuscle is developed upon one side only of the arterial
wall, upon which it then appears to be sessile ; whilst in other instances and this
is the most frequent in the human subject the expansion takes place all round the
circumference of the vessel, by which it then appears to be pierced. In either case
the artery sends off radiating branches to be distributed in the Malpighian
corpuscle.



300 THE DUCTLESS GLANDS.

As just stated, the Malpighian corpuscles are localisel expansions of the
lymphoid tissue of which the external coat of the smaller arteries of the spleen is
formed, and have apparently been produced by increased multiplication of lymph-
cells at the spots in question. The reticulum of the tissue is comparatively open,
being almost absent towards the centre of the corpuscle : at the confines it becomes
closer ; there is, however, no distinct boundary separating it from the retiform
tissue of the pulp. The meshes are densely packed with lymphoid corpuscles, and
the tissue is traversed by capillaries.

The small arteries, after leaving the Malpighian corpuscles, terminate in capillary
vessels, which soon lose their tubular character, the cells which compose their wall
becoming partially separated from one another by elongated clefts ; those at the
extremity of the capillary have branching processes and are united by these with
the branched connective-tissue cells of the pulp. In this manner the blood can flow
directly into the interstices of the pulp tissue. The veins, which form a network
of intercommunicating spaces within the pulp, commence in the same manner as the
capillaries terminate ; that is to say, the layer of flattened cells which lines and
mainly composes their walls, on being traced back, loses its epithelioid character,
and the cells, becoming thickened and spindle-shaped and their nuclei prominent,
are found to be separated here and there from each other, and to be connected by
processes with the cells of the pulp (fig. 306). The small veins take a different
course from the arteries, for they soon pass to the trabeculae and are conducted upon
and within these, freely joining and anastomosing ; whereas the arteries appear to
have few or no anastomoses within the substance of the organ.

The small veins within the pulp of the human spleen often exhibit peculiar
transverse markings. These are produced by fine elastic fibres of the reticulum,
which encircle the vessels. Structures which have been described as " ellipsoids,"
which are in fact condensations of the reticular tissue of the spleen pulp not loaded
with leucocytes as in the Malpighian corpuscles, are often found encircling the
terminations of the arterioles. They are stated by Miiller (bird) and Whiting (cat)
to be surrounded by a special vascular sinus, but this is denied for the cat by Carlier.

From the description above given, it would appear that the blood in passing
through the spleen is brought into immediate relation with the elements of the pulp,
and no doubt it undergoes important changes in the passage ; in this respect
resembling the lymph as it passes through the lymphatic glands. Two modifica-
tions which are probably effected in it may be here pointed out. In the first place
the lymphoid tissue ensheathing the arteries, together with that composing the
Malpighian corpuscles, would appear like the same tissue in the lymphatic glands,
and other parts, to be the seat of the production of pale blood corpuscles. At the
circumference of this tissue, these may pass into the interstices of the pulp, and so
into the blood. It is found, in fact, that the blood of the splenic vein is extremely
rich in pale corpuscles. In the second place, red blood-corpuscles may be taken up
by the pulp-cells, their colouring matter being transformed into pigment. The
splenic cells have, indeed, been noticed, when examined on the warm stage, to take
red corpuscles into their interior. Finally, if it be the case that nucleated red
corpuscles occur normally in the spleen, it is probably also a seat of formation of
coloured blood corpuscles.

The lymphatics of the spleen .form two systems, a irabecular and aperivascular.
The vessels belonging to the former system run in the trabeculae and are in com-
munication with a superficial network in the capsule. The perivascular lymphatics
take origin in the interstices of the lymphoid tissue which ensheaths the smaller
arteries, and which forms the Malpighian corpuscles ; they do not, therefore, at
first form distinct vessels. When these are seen they commonly run in pairs, one
on either side of an artery, uniting over it by frequent anastomoses, and sometimes



THE SPLEEN. 301

partially or wholly enclosing it. At the hilum the two sets of lymphatics join one
another and proceed along with the main blood-vessels, and ultimately pass into
lymphatic glands at the back of the abdomen.

The nerves, derived from the solar plexus, surround and accompany the splenic
artery and its branches. They are most probably distributed to the vessels and
plain muscular tissue of the framework.



RECENT LITERATURE OF THE SPLEEN.

Ballantyne, J. W., The relations of the abdominal viscera in the infant, Edinburgh Meil. Jour.,
July, 1891.

Bannwarth, Untersuchungen iiber die MHz, Archiv f. mikroskop. Anat. , Bd. xxxviii., 1891.

Bohm & v. Davidoflf, Ilandbuch der Histologie, Leipzig, 1895.

Cunning-ham, D. J., On, the form of the spleen and the kidneys, Journ. of Anat. and Physiol.,
vol. xxix., 1895.

Carlier, The minute structure of the reticulum in the cat's spleen, Journ. of Aiiat. and Physiol.,
vol. xxix.. 1895.

Denys, Note preliminaire sur la structure de la rate et sur la destruction de globules rouges qui
s'opere normalement d Vinterieur de cet oryane, Bulletin de 1'acadomie royale de medecine de
Belgique, 1888.

Eliasberg-, Miron, Expcrimentelle Untersuchunyen ubcr die Blutbilduny in der Milz der
Saugetiere, Dorpat, Inaug. Diss. , 1892.

Fusari, Romeo, Stil modo di distribuirsi delle fibre nervose nel parenchima della milza, Monitore
zoologio italiano, anno iii. , 1892.

Hoyer, H., Ueber den Bau der Milz, Morphol. Arbeit., Bd. iii., 1893.

v. Koelliker, A., Die Nerven der Milz und der Nieren und die GaUencapillaren, Sitzgsber. d.
Wiirzb. phys.-med. Ges., 1893.

v. Kupffer, C., Ueber die EntwicTcduny der Milz und Pancreas, Munch, med. Abhandl.,
Miinchen, 1892.

Lag-uesse, E., Le tissu splenique et son devcloppement, Anatom. Anz., Jahrg. vi., 1891.

Oppel, A., Ueber Gitterfasern der menschl. Leber u. Mih, Anat. Anz., Jahrg. vi., 1891.

Toldt, Zur Anatomic der Milz, Wiener med. Wochens^h., 1889.



302



THE DUCTLESS GLANDS.



SUPRARENAL CAPSULES.

The suprarenal bodies or capsules (capsules atralilaricv seu renes succenturiati
of old anatomists), also frequently termed " adrenals," are two flattened bodies,
each of which surmounts the corresponding kidney (fig. 309). They are both

Fig. 309. FRONT VIEW OP THE EIGHT KIDNEY AND SUPRARENAL BODY OF A
FULL GROWN FCKTUS. (Allen Thomson. )

This figure shows the lobulated form of the foetal kidney, r ; v, the renal
vein and artery ; u, the ureter ; s, the suprarenal capsule, the letter is
placed near the sulcus in which the large veins (v'} are seen emerging from
the interior of the organ.

situated in the epigastric region, one on each side of the
vertebral column. They differ from one another in shape
and also in their relations. The right capsule has a
flattened triangular form, one surface called anterior looks
forwards and outwards, and the other, the posterior, back-



Online LibraryJones QuainQuain's Elements of anatomy (Volume 3:4) → online text (page 37 of 44)