24 SUPERFICIAL ANATOMY OF THE TRUNK. 



part to be referred to these. Anteriorly, the rectus muscle extends on each side of 

 the middle line from the pelvis to the thorax, its tendinous inscriptions producing 

 transverse furrows, of which two are commonly to be recognized, one opposite, or 

 just below, the tip of the eusiform process, and the other about midway between 

 this and the umbilicus. In some cases the third may be distinguished about the 

 level of the umbilicus. Between the two recti is a median groove (abdominal 

 furrow} continued downwards from the infrasternal fossa, along the surface of the 

 linea alba, as far as, or a little beyond, the umbilicus, where it gradually disappears 

 owing to the approximation and eventual union of the muscles of the two sides. 

 The lower ends of the recti are concealed by a small accumulation of fat. 



The position of the umbilicus is subject to considerable variation, but it is 

 always below the centre of the distance between the xiphi-sternal articulation and 

 the pubic symphysis. It is generally on a level with, or slightly above, the highest 

 point of the iliac crest, and opposite the upper part of the fourth, or the dis 

 between the third and fourth lumbar vertebras. 



A line joining the two anterior superior iliac -spines usually passes just above the 

 promontory of the sacrum. 



The convex surface of the side of the abdomen is formed by the fleshy part of 

 the external oblique muscle, the outline of which can often be seen in front and 

 below. Between this and the outer edge of the rectus there is a shallow depression 

 over the upper portion of the linea semilunaris : this depression terminates above 

 at the margin of the thorax, in the somewhat triangular infracostal fossa, the upper 

 boundary of which is formed by the rounded ninth costal cartilage. 



In the inguinal region, the superior set of glands may usually be felt lying along 

 Poupart's ligament. The external abdominal ring is placed immediately above 

 and external to the pubic spine, which can always be readily felt, as well as the 

 common attachment of the outer pillar of the ring and Poupart's ligament. By 

 invaginating the scrotum at some distance from the aperture, the ringer may be 

 passed through the ring into the lower part of the inguinal canal. The internal or 

 deep abdominal ring is situated about half an inch (1 cm.) above Poupart's ligament, 

 opposite a spot midway between the anterior superior iliac spine and the pubic 

 symphysis ; and the deep epigastric artery runs upwards close to the inner side of 

 this opening, in the direction of a line inclining inwards towards the umbilicus. If 

 the inguinal canal has been enlarged by the presence of an old hernia, the rings 

 are almost opposite to one another, and the finger may be passed through them and 

 can explore the surrounding parts in the interior of the abdomen. 



The superficial epigastric vein is often seen through the skin, and it may 

 frequently be observed to communicate with another vein (v. thoraco-epigastrica) 

 that passes up into the armpit to join the axillary vein, especially if there be any 

 obstruction to the return of the blood through the inferior vena cava. 



Abdominal viscera. The liver, which occupies the whole of the arch of 

 the diaphragm on the right, as well as a part on the left side, is placed for the 

 most part under cover of the ribs. In the right hypochondriac region, its lower 

 margin just corresponds to the lower border of the thorax, but in the epigastric 

 region, a part of both right and left lobes comes into contact with the abdominal 

 wall ; the margin of this part runs obliquely across the subcostal angle from the 

 ninth right to the eighth left costal cartilage, and crosses the middle line about a 

 hand's breadth below the xiphi-sternal articulation. The gall-bladder projects 

 beyond this margin immediately internal to the ninth costal cartilage, and close to 

 the outer edge of the rectus muscle, i.e., opposite the infracostal fossa. The extent of 

 the liver upwards, if traced on the surface of the body, is marked by a line crossing 

 the body of the sternum close to its lower end, and rising on the right side to the 

 level of the fifth chondro-sternal articulation, on the left to that of the sixth. A 



