1370 CLINICAL AND TOPOGRAPHICAL ANATOMY 



pericardium. Its lymphatics go below into the posterior mediastinal and superior 

 gastric nodes; above into the lower deep cervical nodes, a point sometimes diag- 

 nostic in malignant disease. 



The lumen of the oesophagus is narrowed at three points: — (1) and best marked at the cri- 

 coid cartilage, (2) where it is crossed by the left bronchus, (3) as it passes through the dia- 

 phragm. The tulae, 25 to 27 cm. (10 to 11 in.) long, extends from the sixth cervical to the lower 

 border of the tenth thoracic vertebra. In an adult, the distance from the incisor teeth to the 

 cricoid is about 15 cm. (6 in.); an additional 7.5 cm. (3 in.) gives the level of the crossing of 

 the left bronchus, while from the teeth to the opening in the diaphragm would be from 41 to 43 

 cm. (16 to 17 in.). To expose the tube in the neck an incision is made on the left side, much 

 as for the higher ligature of the common carotid, but carried lower down. The depressors of 

 the hyoid being drawn medially or divided, the pretracheal fascia is opened, which allows of 

 the overlapping thyreoid and trachea being displaced medially, while the carotid sheath is re- 

 tracted laterally. The tracheal rings are the best guide to the oesophagus. The recurrent 

 nerve must be avoided. 



THE ABDOMEN 



The regions and subdivisions will first be considered, the abdominal wall 

 next, and finally the abdominal cavity, including the peritoneum and the various 

 organs. 



Subdivision of the abdominal cavity. — Certain arbitrary horizontal and 

 vertical planes, represented by lines drawn on the ventral surface, are used to 

 subdivide the abdomen for topographical purposes (fig. 898). A. Horizontal 

 planes. (1) Infracostal through the lower margins of the tenth costal cartilages 

 (the lowest part of the costal margin). This plane crosses the body of the third 

 lumbar vertebra. (2) Intertubercular, passing through the tubercles, prominent 

 points of the iliac crests, which are situated about 5 cm. (2 in.) behind the anterior 

 superior spines. This plane crosses the body of the fifth lumbar vertebra. 

 B. Vertical planes. (1) Median vertical, drawn upward in the middle line 

 from the symphysis pubis. (2) Lateral vertical, drawn upward on each side 

 parallel to the former, from a point midway between the anterior superior iliac 

 spine and the symphysis pubis. 



These lateral lines if prolonged upward into the thorax pass rather more than 2.5 cm. 

 (1 in.) to the medial side of the male nipple and meet the clavicle a little medial to its mid-point. 



According to the BNA system, the lateral vertical lines are slightly curved, extending 

 upward from the pubic tubercle on each side along the lateral margin of the rectus muscle 

 (corresponding to the linea semilunaris). 



The infracostal and intertubercular planes, with the two lateral vertical 

 planes that intersect them divide the abdomen into nine regions: — three median, 

 viz., the epigastric, umbilical, and hypogastric and on each side three lateral, viz., 

 hypochondriac, lumbar, and iliac (fig, 898). 



Another transverse plane of practical importance, though we do not use it as a boundary 

 of the abdominal subdivisions, is represented by Addison's transpyloric line, drawn horizontally 

 through a point midway between the umbilicus and the sterno-xiphoid junction (or midway 

 between the symphysis pubis and supra-sternal notch). It crosses the spine at the level of 

 the first lumbar vertebra. It must be noted that the pylorus only lies in this plane during 

 life when the subject is in the horizontal position. On assuming the upright position the pylorus 

 falls at least one vertebra lower. The sterno-xiphoid plane, drawn horizontally through the 

 junction of the body of the sternum with the xi|)hoid, cuts the spim; at the disc between the 

 ninth and tenth thoracic vertebric, aiid tlie umbilical plane, passing through the umbilicus, 

 crosses the disc between the third and fourth lumbar vertebra- (though in corpulent subjects it is 

 somewhat lower). 



The abdominal wall. Bony and muscular landmarks. — The linea alba 



forms a perceptible groove in the middle line from the xiphoid cartilage to below 

 the umbilicus. It is a band of interlacing fibres, mostly crossing each other at 

 right angles, that forms the main insertion of the transversus and oblique 

 muscles, and stretches between the two recti muscles from xiphoid cartilage to 

 symphysis. It is on the average 1.2 cm. (| in.) wide above the umbilicus. Below 

 the umbilicus it narrows rapidly and becomes merely a thin fibrous septum 

 between tiie two recti, which in tiiis position lie close together. 



In its broad supra-umbilical portion, .small hernial protrusions of subperitoneal fat often 

 force their way through interstices in the linea alba, and true peritoneal sacs may be drawn 

 through after them. The linea alba is not very vascular, and hence was at one time the favour- 



