1114 SURGICAL AXD TOPOGRAPHICAL ANATOMY 



the left of the sternum, straight upwards to the clavicle, delineates the vertical 

 thoracic c<»nrs(> of the long left subclavian artery (Sheild). 



Innominate veins. — The left, three inches long, extends very oblicjuely from 

 the left sterno-clavicular joint, to a i)oint half an inch to the right of the sternum, 

 in the first intercostal sjtace. The right, al)out an inch long, descends almost 

 vertically to the above ])(>int from the right sterno-clavicular joint. 



Venae cavae. — The superior descends from the point above given for the 

 meeting of the innominate veins in the first intercostal space, close to the sternum, 

 and ]ierforates the right auricle on a level with the third costal cartilage. The 

 inferior vena cava. — The opening of this vein into the right auricle lies under the 

 middle of the fifth riglit intersi)ace and the adjacent part of the sternum. 



Internal mammary artery. — This descends l)ehind the clavicle, the costal 

 cartilages, and the first six spaces, about half an inch from the edge of the 

 sternum. In the sixth intercostal space it divides into musculo-phrenic and 

 superior epigastric arteries. 



Till: ABD03IEN 



Skin markings ; bones and muscular landmarks. — The linea alba, or 

 meeting of the aponeuroses of the great abdominal muscles over, under, and 

 between the recti, reaches from the apex of the xiphoid cartilage to the symphysis. 

 It is best marked above the umbilicus. Its little vascularity and comparative 

 thinness fit this line for the point of election for many of the operations on the 

 abdominal cavity. In the linea alba, a little below its centre, is the umbilicus. 

 This corresponds to the level of the fibro-cartilage between the third and fourth 

 lumbar vertebrae, the tip of the third lumbar spine (Windle), the highest point of 

 the iliac crests, and a point three-quarters of an inch to one inch above the bifur- 

 cation of the aorta. 



On each side of the linea alba, and about two and a half to three inches from 

 it (according to the muscular development), a line, curved with a slight convexity 

 outwards, the linea semilunaris, denotes the point of division of the abdominal 

 aponeuroses, reaching from the ninth costal cartilage to the pubic spine. Between 

 the linea alba and the linea semilunaris run the three linese transversa^ of which 

 one is placed at the uml^ilicus, another at the xiphoid cartilage, and a third between 

 the two, on a level with the tenth costal cartilage. There is, rarely, a fourth below 

 the umbilicus. 



In very corpulent subjects two deep transverse furrows run across the abdomen. 

 One runs across the navel and completely conceals it; the other is lower down, 

 just above the fat of the pubes. In tapping the bladder above the pubes in 

 such a case, the trocar should be introduced where this line intersects the linea 

 alba (Holden). 



A transverse line drawn from one anterior superior spine to the other crosses at 

 about the level of the top of the promontory of the sacrum. Such a line will 

 always show whether the pelvis is horizontal or not (Holden). 



Poupart's ligament corresponds to a line drawn with a slight curve down- 

 wards between the anterior superior spine and the pubic spine. The first of these 

 bony prominences corresponds to the starting-point of the above ligament, the 

 attachment of the fascia lata to the ilium, the meeting of the fieshy and aponeu- 

 rotic parts of the external oblique (denoted by a line drawn upwards from this 

 spine to the ninth costal cartilage, or often a little anteriorly to these i)oints), the 

 point of emergence of the external cutaneous nerve, and part of the origins of the 

 internal oblique, transversalis. and t(msi)r vaginre femoris. The pubic spine marks 

 the outer pillar of the external abdominal ring, the mouth of which corresponds 

 to the crest, or that part of the pubes lying between the spine and tlie symphysis. 



I 



