THE STOMA CH 1 28 1 



more, as the constriction advances, a thin stream of food is continuously forced back through 

 the ring and thus past the mouths of the glands. The old view that the pyloric sphincter only 

 opens after several hours' continuance of the process of digestion, and that then the stomach 

 empties at once, is incorrect. It is emptied in small amounts, which escape at frequent intervals 

 because of the intermittent opening of the pylorus. When the pylorus is open a wave of peri- 

 stalsis forces some of the material from the stomach into the duodenum (Cannon). 



Cannon is of the opinion that the pyloric sphincter is caused to relax by the presence of free 

 hvdrochloric acid in the pyloric portion of the stomach. When the pylorus is open acid chyme 

 passes into the duodenum, and acid in the duodenum causes the pylorus to close. The acid 

 in the duodenum causes a flow of alkaline pancreatic juice and the acid is neutralized. "As 

 the neutralizing proceeds, the stimulus closing the pylorus is weakened until the acid in the 

 stomach again opens the sphincter." 1 



Innervation. The stomach, as previously shown, has nerve plexuses in its walls and is 

 connected to the cerebrospinal and sympathetic systems. It is probable that gastric peristalsis 

 is due to a local reflex from Auerbach's plexus (Magnus), the local reflex being inaugurated by 

 local stimulation, which stimulation, in the words of Bayliss and Starling, "produces excitation 

 above and inhibition below the excited spot." 2 Reversed peristalsis cannot occur if "the reflex 

 mechanism is intact" (Cannon). Cannon in the previously quoted article states that cutting 

 the vagi or splanchnic nerves does not destroy the reflex mechanism of the pylorus, but, never- 

 theless, it is markedly affected by the central nerve system. 



Surface Form (see p. 1241). The cardiac orifice corresponds to the articulation of the seventh 

 left costal cartilage with the sternum. The pyloric orifice of the empty stomach is about an inch 

 to the right of the midline in the transpyloric line. According to Braune, when the stomach is 

 distended, the pylorus moves considerably to the right, sometimes as much as three inches. 

 The fundus of the stomach reaches, on the left side, as high as the level of the sixth costal car- 

 tilage of the left side, being a little below and behind the apex of the heart. The portion of the 

 distended stomach which is in contact with the abdominal walls, and is therefore accessible for 

 opening in the operations of gastrotomy and gastrostomy, is represented by a triangular space, 

 the base of which is formed by a line drawn from the tip of the tenth costal cartilage on the left 

 side to the tip of the ninth costal cartilage on the right, and the sides by two lines drawn from 

 the extremity of the eighth costal cartilage on the left side to the end of the base line. What is 

 commonly termed the semilunar space of Traube is that portion of the stomach which is not 

 covered by neighboring viscera. It is bounded above by the left lobe of the liver and the inferior 

 margin of the left lung, posteriorly and to the left by the spleen; on percussion, this area is nor- 

 mally tympanitic. 



Applied Anatomy. Operations on the stomach are frequently performed, ulcers are excised, 

 malignant growths are removed with the associated lymphatic involvement, the entire stomach 

 may be removed for cancer, etc. By "gastrotomy" is meant an incision into the stomach for the 

 removal of a foreign body, or the arrest of hemorrhage, or for exploration, the opening being 

 immediately afterward closed in contradistinction to "gastrostomy," the making of a more or 

 less permanent fistulous opening. Gastrotomy is probably best performed by an incision in the 

 linea alba, especially if the foreign body is large. The cut may reach from the ensiform car- 

 tilage to the umbilicus. The incision may be made over the body itself, where this can be felt, 

 or by one of the incisions for gastrostomy, to be mentioned shortly. The peritoneal cavity 

 is opened, and the point at which the stomach is to be incised decided upon. This portion is 

 then brought out of the abdominal wound and sponges carefully packed around. The stomach 

 is now opened by a transverse incision and the foreign body extracted. The wound in the 

 stomach is then closed by Lembert sutures -i. e., by sutures passed through the peritoneal, 

 muscular, and submucous coats in such a way that the peritoneal surfaces on each side of the 

 wound are brought into apposition. Gastrostomy was formerly done in two stages by the direct 

 method. The first stage consisted in opening the abdomen, drawing up the stomach into the 

 external wound, and fixing it there; and the second stage, performed from two to four days 

 afterward, consisted in opening the stomach. The operation is now done by a valvular method. 

 The following plan is known as the Ssabanejew-Frank operation. An incision is commenced 

 opposite the eighth intercostal space, two inches to the left of the median line, and carried down- 

 ward for three inches. By this incision the fibres of the Reetus muscle are exposed and these 

 are separated from one another in the same line. The posterior layer of the sheath, the trans- 

 versalis fascia, and the peritoneum are then divided, and the peritoneal cavity is opened. In- 

 stead of the above incision, the curved incision of Fenger can be made af the margin of the left 

 costal cartilages. The anterior wall of the stomach is now seized and drawn out of the wound 

 and a silk suture passed through its submucous, muscular, and serous coats at the point selected 

 for opening the viscus. This is held by an assistant so that a long conical diverticulum of the 

 stomach protrudes from the external wound, and the parietal peritoneum and the posterior layer 

 of the sheath of the Rectus are sutured to the base of the cone. A second incision is made through 



Walter B. Cannon, Medical News, May 20, 1905. 2 Ibid. 



81 



