The proximal portion of the diverticulum is here still closely connected to the small intestine along which it extends, both being surrounded by the common visceral peritoneum.
In some birds the small intestine is also provided with a caecal pouch, the remnant of the vitello-intestinal duct corresponding in its significance to the occasional mammalian diverticulum of Meckel (Figs.
Duodenum, with entrance of pancreatic and biliary ducts and well-developed diverticulum Vateri in the cassowary, Casuarius casuarius (Columbia University Museum, No.
The membrane in the region of this diverticulum turns its surfaces dorsad and ventrad, and its free edge toward the right (Fig.
A caecal pouch or diverticulum in some form at the junction of mid- and hindgut is a very common and widely distributed mammalian character.
An example of partial persistence of the omphalo-mesenteric artery in the adult is well seen in the case of Meckel's diverticulum shown in Fig.
This caecal pouch is usually considered as a hepatic diverticulum (Fig.
The intestinal opening of the diverticulum is situated at a varying distance above the ileo-colic junction, ranging from 27.
The descending limb, apex (site of embryonic vitelline duct, Meckel's diverticulum of adult) and a short succeeding portion of the ascending limb furnish the ileum and jejunum.
The union of the pancreatic and biliary ducts to form the recess of the diverticulum Vateri, which then opens by a single common orifice into the duodenum, is better marked in some of the lower vertebrates than in man.
The short stretch of the primitive alimentary canal cephalad of the hepatic diverticulum corresponds to the foregut.
Thus but a single diverticulum appears in Polypterus and Ammodytes (Fig.
In Sepia the two renal sacs give off each a diverticulum dorsalwards, which unites with its fellow and forms a great median renal chamber, lying between the ventral portions of the renal organs and the viscero-pericardial chamber.
The vas deferens is at first narrow and convoluted, then dilates into a vesicula seminalis at the end of which is a glandular diverticulum called the prostate.
An ink-sac formed as a diverticulum of the rectum and opening near the anus is present in all Dibranchiata (fig.
This diverticulum contains the blood-vessel and muscle-fibres (fig.
The small arm-sinus runs along the arms of the lophophore at the base of the tentacles, and gives off a blind diverticulum into each of these.
Jaw lever (cuticular prolongation of inner jaw lying in a backwardly projecting diverticulum of the buccal cavity).
Median backward diverticulum of mouth or common salivary duct which receives the salivary ducts.
On the inner wall of this diverticulum a projection is formed which becomes a glomerulus.
It then has the form of a funnel-shaped diverticulum of the dorsal wall of the duodenum, immediately behind the level of the opening of the bile duct.
This diverticulum is wide at first and opens by a somewhat constricted mouth into the pharynx above (Pl.
Into this part a narrow diverticulum from the end of the medullary groove is continued for a very short distance (vide fig.
Traction diverticulumof the esophagus rendered visible in the roentgenogram by a swallowed opaque mixture.
Respiratory arrest may occur from shifting of a foreign body, pressure of the esophagoscope, tumor, or diverticulum full of food.
It has been the chagrin of skilled surgeons to find the diverticulum present functionally and roentgenographically precisely the same as before the performance of the very trying and difficult operation.
Unless a very large esophagoscope be used, a traction diverticulum may easily be overlooked in the mucosal folds.
Pulsion diverticulum filled with bismuth mixture in a man of fifty years.
There is great danger from tracheal pressure by an esophageal diverticulum or dilatation distended with food; or the food maybe regurgitated and aspirated into the larynx and trachea.
Pulsion diverticulum of the esophagus is an acquired hernia of the mucosa between the circular and oblique fibers of the inferior constrictor muscle of the pharynx.
Schematic representation of esophagoscopic aid in the excision of a diverticulum in the Gaub-Jackson operation.
Such is Goette's account of the prae-oral body space, but, as he himself points out, it involves our believing that the lining of the diverticulum derived from the primitive alimentary vesicle becomes part of the external skin.
The alimentary diverticulumof the last stage becomes an independent vesicle opening by a pore on the dorsal surface (fig.
If this lower part of the ovarian tube were to grow out as a special diverticulumwe should have produced a normal vitellarium.
The former remains as a simple diverticulum through larval life, but the latter becomes an extremely complicated glandular structure.
It leads into a stomach from which an anterior and a lateral hepatic diverticulum springs out on each side.
Hoffman also states that the epithelium of the proboscis is formed as a diverticulum of the alimentary tract, and that its sheath is formed by a special mesoblastic growth.
The diverticulum becomes the madreporic canal, and the opening the dorsal pore.
A contractile band passes from the oesophagus to the apex of the prae-oral lobe, and a diverticulum (fig.
Attached to it is a diverticulum fl, in which the spermatozoa which have descended from the ovo-testis are stored and modelled into sperm ropes or spermatophores.
The latter opens into the common duct at the point k, and here also is a small diverticulumof the duct f.
The diverticulum is usually located in the upper portion of the oesophagus, just below the inferior constrictor muscle of the pharynx.
One {432} of the special indications of diverticulum is that the regurgitation does not take place until several hours after a meal.
A calculus may be retained in a fold or diverticulum of the small intestine, and may indeed cause a loop to be formed which in turn readily twists, becoming an immovable obstruction.
In some cases of diverticulum high up, there is a tumor, usually on the left side of the neck.
Sometimes the diverticulum drags the oesophagus out of position and forms a sort of blind pouch in the direct line of its axis, so that it becomes filled with food which fails to reach the stomach.
A diverticulum is thereby made (Vater's) in which a concretion may lodge, partly or wholly preventing the escape of bile into the bowel.
Just behind and to the right of its orifice the duct is dilated into a fossa--the diverticulum Vateri; and here concretions of a size to pass along the common duct are stopped.
The size of the diverticulum varies; a common size is that of a duck egg, but the size of a fist has been attained.
The foreign body, however, if small, may drop into the appendix vermiformis or some other diverticulum and end in serious mischief, or if the individual has stricture of the bowel the foreign body may be arrested by it.
An appearance of the natural relations of the diverticulum to the intestine.
Oesophagocele, Hernia of the oesophagus, Diverticulum of the oesophagus.
Again, the diverticulummay contain numerous concretions, which distend the canal greatly, but through the interstices of which some bile can flow.
Should the diverticulum be inaccessible from the neck, and the difficulty of swallowing be attended with progressive emaciation, gastrostomy may be required to avert death by starvation.
Diverticulum of the Œsophagus at its junction with the Pharynx.
These may originate in a diverticulum of a vein that has become isolated, or in a cavernous angioma; or they may be due to hæmorrhage taking place into a branchial or thyreo-glossal cyst.
A diverticulum consists in the protrusion of the mucous and submucous coats through a defect or weak part in the muscular tunic; it is therefore of the nature of a hernia and not a localised dilatation of the tube as a whole.
All that can be said is, that the formation of the duct takes place at a time when the pronephric diverticulum is in close propinquity to the epidermis, before the ventral downgrowth of the myotome has taken place.
It follows, therefore, that the nutrient fluid absorbed by the cells of this part of the gut-diverticulum must be primarily for the service of the retinal ganglion.
Just posterior to the branchial part a diverticulum of the gut was formed at an early stage, as seen in Amphioxus, and provided the {452}commencement of the liver.
In its origin the lung or air-bladder arises as a diverticulumfrom the alimentary canal, used by the earliest fishes as a breathing-sac, the respiratory functions lost in the progress of further divergence.
The liver in the lancelet is a longdiverticulum of the intestine.
In some few sharks, indeed, there is a diverticulum of the pharynx which may be a rudimentary approach to the air-bladder; but this is very questionable.
In the Acrania (Amphioxus) the liver is probably represented by a single ventral diverticulum from the anterior end of the intestine, which has a hepatic portal circulation and secretes digestive fluid.
From the cephalic part of this primary diverticulum solid rods of cells called the hepatic cylinders grow out, and these branch again and again until a cellular network is formed surrounding and breaking up the umbilical and vitelline veins.
Naturally, in birds where the yolk-sac is of great functional importance this diverticulum is large, and in a majority of the families of birds persists throughout life, forming a convenient point of orientation.
In the same region of the body, namely, close behind the pharynx, a large diverticulum is given off from the ventral side of the gut.
It arises as a diverticulum of the gut-wall which may retain a tubular connexion with the gut (physostomatous condition) or may in the adult completely lose such connexion (physoclistic).
In Selachians a small glandular diverticulum known as the rectal gland opens into the terminal part of the intestine on its dorsal side.
Food reservoir: Lepidoptera, a blind sac or diverticulum from the bind part of oesophagus lying in abdomen dorsal to the stomach.
The hinder diverticulum of the neural canal along the line of the primitive groove is, moreover, very considerable in the chick, and is not so soon obliterated as in the goose.
In the Rabbit a ductus choledochus is formed by a diverticulum from the intestine at the point of insertion of the two primitive lobes.
It subsequently becomes detached from the epidermis, and then has the usual form of a diverticulum from the throat.
The first development of the allantois as a diverticulum of the hypoblast covered by splanchnic mesoblast, at the apparent posterior end of the primitive streak, has been described on p.
In all the higher Vertebrata the thyroid body arises as a diverticulum of the ventral wall of the throat in the region either of the mandibular or hyoid arches (fig.
They have a swollen extremity, and are provided with an endodermal axis for half the length of which there is a diverticulum of the gastrovascular canal system.
The external opening of this passage finally becomes obliterated, and the passage itself is left as a narrow diverticulum leading from the hind end of the mesenteron into the neural canal (fig.
Close to its hinder boundary there appears a ventral outgrowth, which is the commencement of the hepatic diverticulum (fig.
The peculiar connection between the thyroiddiverticulum and the epidermis in Amphibia has been noted by Goette in Bombinator, and by Scott and Osborn in Triton.
In the later stages of development the infundibulum becomes gradually prolonged, and forms an elongated diverticulum of the third ventricle, the apex of which is in contact with the pituitary body (figs.
The first part of this passage to appear is the hypoblastic diverticulum above mentioned.
In advanced embryos of Galeus, Mustelus and Acanthias, Miklucho-Maclay detected a small diverticulum opening on the dorsal side of the oesophagus, which he regards as a rudiment of a swimming bladder.
The cavity of the primitive diverticulum becomes obliterated in front, but behind it opens throughout life into the alimentary canal.
In Cephalodiscus and Rhabdopleura as in Balanoglossus the notochord forms a small diverticulum growing forwards from the alimentary canal into the proboscis stalk.
This arises as a diverticulum from the alimentary canal which grows forwards into the proboscis and extends beyond the front end of the central nervous system.
The diverticulum noted, also, in connection with figure 7, has relatively thick, wrinkled walls; its significance is not known to the writer.
From this diverticulum the duodenum, d, leads caudad and laterad for a short distance as a narrow tube, then suddenly expands into the widest part of the entire intestine.
Cross section through the base of the proboscis showing diverticulum wall and proboscis gland.
Because this diverticulum has the vacuolated appearance of the notochordal tissue of higher animals, it has been regarded as a notochord.
The caecum is a branch or diverticulum of the intestine, ending in a cul-de-sac, and it is extremely long in many of the lower vegetable-feeding mammals.
At this or some earlier period, the intestine gave forth a much larger diverticulum or caecum than that now existing.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "diverticulum" in a variety of sentences. We hope that you will now be able to make sentences using this word.
